Hey, very cool video. Nice pictures too. Fun to watch. How much current feeds into the lead acid to trickle charge them at high SOC? Have you tracked what happens with a shunt between your batteries over a typical night? At low SOC, it would seem the lead acid is reducing the performance of your system. Considering that the LiFePO4 wants to keep the voltage high, you couldn't use most of the capacity of your lead bank. I suppose the bms could disconnect and reconnect, but the differing internal resistances disconnecting and reconnecting seem a bit scary. I suppose the lead acid does act as a buffer. Hmmm. I would have to see how they feed each other over a cycle. That is difficult to do without a data logging device. Have you done that yet? I see, so small lithium battery, big lead bank. Hmm I suppose that is attractive for a marine system. Have you done a full capacity test? How deeply do you discharge your bank? If you keep this bank at high SOC, and none of the cells short, it would probably work fine. Good point about setting absorption at 14V. Very true. The prices of lifepo4 are dropping quickly. I built a 280Ah 12V pack for $580 this week. That is cheaper than high quality lead acid, if coulombic efficiency and usable capacity are taken into consideration. You should try LTO. LiFePO4 is touchy, but that is only if you do not have a BMS. LTO would destroy every downside of LiFePO4 you mentioned. You can discharge at 10C rate! You can start any size engine with a modest size pack. You would love them I bet. Everything you stated in this video screams LTO. I did try paralleling LTO and LiFePO4 some years ago, and it was horrible. My capacity test results were awful. LTO has a wider voltage range, and more linear. And my test results were awful because of it. The cells would feed each other constantly. Very inefficient. Trickle charging lead acid all night with lithium seems very inefficient. I suppose if your loads are small, you can do it. Just that difference in voltage at various SOC makes me cringe. But yeah, do you have any data logged on how the batteries feed each other during a full cycle?? I would love to see it.
Thanks for writing. I've been subscribed to your channel for quite some time now and when I meet sailors with questions about lithium I send them your way first. You do a great channel with reliable information and a very approachable style. I have been living off sun and wind for over 20 years on this boat traveling around the warm parts of the world. I started this hybrid system just over a year and a half ago. I already had a huge (1500ah) agm lead bank in great condition but I wanted to add an air conditioner I was designing and didn't want to cycle the lead that much. The life cycle loss and just plain inefficiencies of lead made that not a great idea. I was first going to set up some kind of DC/DC charge system but soon fell on this idea. I must say it has been working extremely well. So my system consists of just over 1400ah of AGM L-16 sized main house batteries. There is also a small agm and a flooded lead starter battery tied in through a voltage sensitive relay. I added two Battleborn LiFePO4 batteries during my last big refit in the US. With the "rest" voltage differences this system uses most of the power in the Li bank first before dipping into the lead. That is what makes this work so well. Also, as you pointed out, the Lead has a relatively high internal resistance. This actually helps a lot with keeping everything safe. On a typical night even with the use of air conditioning we don't deplete the lithium bank and usually wake to a system voltage of over 13.0 volts. At this state the lead is still fully charged. So it is seldom that the lead goes into low state of charge. It happens only when we have had days without sun or wind. I was surprised to find that the lead bank uses 0.5amps to hold itself at 13.2v. So if we have, say, 14 hours without charging that wastes 7ah of power. That is less then what I would loose through inefficiencies charging and discharging a pure lead bank so I'm ahead of the game ah wise already. When we go several days without sun or enough wind we do dip into the lead. During this time the Li still is very helpful. Lead will not take a charge as fast as Li and often one finds they waste power just regulating it away. With this set up the Li acts as a capacitor in a way accepting all the power and trickling it into the lead later if necessary. Not perfectly efficient but this is a rare occurrence. Over a few days the lead and Li get fully charged and all is well again. Voyaging boats are a bit different then houses and campers. When things fail we often can't go to the shop and get a replacement. And we rely on our power a bit more heavily. Not only do we have lighting and refrigeration but engine starting autopilot and navigation are hard to live without. I've been hit by lightning several times (th-cam.com/video/PurMG7KHdW4/w-d-xo.html) I'm concerned what that would do to a BMS. So having lead on board feels safer. Also, there are a LOT of boats that aren't going to Li until they need to replace there current lead. After all the batteries you already have are free. You might also find this video interesting (th-cam.com/video/sqT27KbxRec/w-d-xo.html) It's sort of the other side of the coin, why you might actually want to add a Lead battery to your Lithium bank. After doing these videos a couple of things have happened. One is my flooded starter battery failed in a dead short manor. It took a while for me to notice since all we had as a symptom was a slowly falling voltage and (I wish I would have noticed this earlier) our water from the taps was getting warmer due to the filters being near the failing battery. There were no real dangers. The system depleted it's self into the bad battery, final system voltage got to 12.6v. I just had to remove the bad battery from the system and start my generator for the first time in years to boost everything back up since we were having a long rainy spell at the time. The other thing that happened turned out even more interesting. Many people questioned how I was charging my batteries. Just charging them together isn't optimum and it got me thinking - what would be perfect? Well, I have since developed a hybrid lithium charge controller. It's at the breadboard stage now but working fine. I just got the components this week so I can solder up the finished model. This device does two things. It disconnects the Lithium part of the bank once they are fully charged so the Lead can charge fully on it's own. And, possibly more importantly, it reconnects the Lithium when both sides of the bank are at the same voltage so there is no large inrush current. This is the key that makes this idea work for more people. I'd like the chance to chat with you about this. Would you be up for a phone call sometime? I have a US number and good data connections here in the Dominican Republic. I'll send you a personal message on the email listed on your website. I expect to do a video on my charge controller soon to finish up this series. I will make the design publicly available and might even do a short production run and sell the units if I find someone on land that is interested to be involved as I can't ship things from the boat especially when I'm voyaging.
@@Clarks-Adventure good points you make about voyage boats. And the lighting and bms. That would surely fry the fets if a long conductor in your system accumulated enough charge to cause voltage spike. Would be fun to measure that. Wow, so many factors in marine systems. Very interesting
@@Clarks-Adventure I would be interested in your beta release of the charge controller. Like many other RVers who have a limited existing system (2x12v FLA batts with 2000w modified sine wave inverter/charger) I am looking to add LiFePO4 batteries to augment my capacity - but I would like to charge those batteries as quickly as possible while running the generator or connected to shore power. I know that's not in your current wheelhouse... but if you have a good idea - I'm all ears.
Hi all, I'm glad so many people are finding this interesting. I'm enjoying all the comments and it seems like you'd like another video or two on the subject. Problem is I just can't keep up with individual technical questions over comments. This subject is a bit complex and relies on a certain knowledge of how electricity works and flows. It seems obvious from the questions that many of you have some misunderstandings in this area. I just can't do a complete answer to your questions and know I'm not adding to the confusion while typing on my little phone screen. My offer to do detailed help over patreon stands. I'll answer simple questions at most levels and at our "dream believers" level I'll do my best to do a proper job with individual analysis of your needs and education over the phone. Also, I had an idea yesterday for a device. Talked to a really talented EE friend back in the states. I think we will make them for sale. It's a lithium battery charger that is made especially for li/lead hybrid systems. Not a dc/dc converter. Allows your existing lead chargers and regulators to charge the li part exactly like it wants to be charged but still charge the lead as it needs. No trade-offs. Do you think people would want such a device?
Your entire video I was trying figure out the best way to charge this system. I actually have a relatively small setup where I am trying to develop systems that are ideal for colder climates that limited amounts of sun. I am currently using 2 100Ah lead and 4 100Ah and a MPPT charge controller and DC-DC charger.
Clark, I'm guessing there may be interest but in my opinion, very few will be willing to pay. The typical boater will not do anything unless there is a need. Take me for example, the bank on the boat we purchased was AGM of a unknown age however the PO seems to remember having them replaced about 12 years ago. Last spring they where flat and I was unable to bring them back so investigation of the replacement type began. I do not assert that I am an expert in the battery field but based on my circumstances, the choice was relatively easy. Our boat came with a quality 30 amp marine smart charger and a high output alternator setup for AGM. I am also some what of a thrifty individual and only plan on owning the boat for a maximum of five years. Those circumstances pushed me to AGM as the replacement as lithium ROI comes from the long term. Our new three house bank batteries come in under 300 ah and we run the normal anchor out/navigation loads plus a 24/7 Iceco portable 12 vdc compressor freezer ( I like ice cream, seafood and meat). The battery bank (from Battery Plus) has a three year replacement warrenty. I am able to run the original ice box refrigeration but not continuously but it works for us. Adding solar this coming season (probably 400 watts max) which may help with the built in frig run time. We do have a slip but typically anchor out three to four nights a week and will be traveling through the Great Lakes and East Coast and beyond once we feel comfortable traveling again. OK so I fall into the lazy/cheap group as noted above. The other obstacle you will have to consider is the battery vendors themselves, pretty sure you have difficulty finding any of them who will warrenty mixed types. The last potential obstacle I anticipate, is it has to meet code so insurance companies cover losses. Anyway, appreciate the opportunity to respond to your question.
Thanks for posting a link to my Article :) It is early days since I made my Hybrid Lithium-Lead (more precisely Hybrid LiFePO4-PbC) Bank but from the analysis (not just the three days used for the charting in the writeup but continuous 24/7 minute-by-minute data logging over many charge and discharge cycles), I am convinced the theories convert to a practical setup with some distinct advantages over pure lead OR pure lithium.
I've thought about this too before, it's what we do with hard drives in large storage systems. Solid state disks do all the day to day work, but mechanical disks do all the long term heavy lifting. Glad someone did more digging on the subject! Great video Clark. 👌🏼
This makes so much sense. Most people so far knock either one or the other, but what you say makes so much sense. As I’ve said many times. I never watch an Emily and Clark episode that I don’t learn something. I hope to be building a system in the future, and this is fantastic insight and information. Isn’t it interesting how having an open mind can lead to better understanding.
I have been putting together a big system on my boat and had this idea for a different reason. Lithium can take a charge faster than lead, and lead benefits from being float charged to get from 85-90% up to 100%, but it takes a LONG time. So my idea was charge everything until the lead hits 80% (at which time the Lithium should be fully charged). Then shut down the generator and have the lithium - through a battery to battery charger like the Sterling or Victron- to bring the lead up to max over the next few hours. Now you have a full lead bank, but a lower lithium bank. To your point, you can now use the lead to supplement the lithium through a smart battery connect until the lead hits 50%. At that point the lithium can go a little longer until its at 30%. At that point you have to re-charge. Main point is you can reduce your charge time as the charge acceptance rate of the lithium is so much higher than the lead. This assumes no solar. Of course, if you have solar, charge time is even lower as the solar - or wind - has reduced discharge. We both agree, reducing generator run time is the goal! Great idea and great video.
I really appreciate your channel. I’m a photographer going “digital nomad” living in a sailboat outside of Stockholm. I’m following the Dream but haven’t a clue about living in a boat, thank you so much for these absolutely down to Earth tips🙏
Clark, I know this was 3 years ago and you have subsequently updated and improved with the development of your Bank Manager. But this has to be one of the most influential videos on TH-cam - I've seen it cited all over the place and it has clearly influenced a lot of people. After about a year of internal debate with myself I decided recently to go down this route pretty much as you laid out here and it feels like a complete game changer. Heading out on the boat for a month next week so that will be the real tell! Have not installed a Bank Manager (yet) because the protections provided by the BMS in my new Renogy PRO LiFePo4 battery together with the ability to control charging profiles leads me to believe I don't need it. But time, again, will tell! But thank you for your contributions to the sailing community which go far beyond this one video.
You are very welcome. Yes the ISO contacted me and asked me to write the bases for their hybrid battery standard because of this video. I do very much disagree with the level of protection you are getting from your BMS but we all get to do what we want. I believe in freedom. But I do feel bad for your batteries, they deserve a longer life than 3 to 6 years. :)
Thanks. That's so nice to hear. Please tell your friends and share our video links on social media, we could use the views. We aren't getting that many. I'm beginning to understand people don't care about informative. The video on the air-conditioning system will likely be the next technical video we do. Emily just got out of the hospital today so I'm not sure of our schedule.
started with vhf, now i am addicted .. i have a red jacket, 17fy its my learner vessel. i live in whyalla so i have flat waters to learn, and teach my son.. we watch your vids every time he asks a question, to learn together thanks so much for your share
Clark I have been,researching the whole agm / lithium battery issue for a couple of months you just saved my 500 amps of agm and me about 2k on lithium I think 150amps of lithium will be fine but now I need to wait for your A/C video before I make my decision.,like the way you think, thankyou you for sharing
great info . i found this info on a battery forum about a year ago . and have a van solar set up with 3 x 100ah lifepo4's in a string . and use a manual isolator linking to the start battery , therefore intern also the alternator . i use the lead combined for big inverter loads like A/C as well . i've been throwing that switch sporadically for around a year now . i have the victron smart shunt and can tell you -- with the start battery at 12.5v and the lithiums at 14.2v it only shifts a couple hundred watts for a few seconds .and ramps down quickly , i have never burned out a switch or a wire . or anything . so i'm going to say in this respect to this ,you are being over pedantic with the volt matching .great video though . i had to search hard for this info 12 months ago . so big ups for the added knowledge . it's true they work great together .
You are being saved by the fact you don't have much of a lead bank. Lead has high resistance but if you put a lot of it in parallel it can really suck in the amps. For example my boat has 1500ah if lead. But glad to hear your data. Thanks. It helps me, especially when I start selling these controllers to vans and small boats. You might still like one of these circuits. Just so you can forget throwing the switch. My controller actions an external contactor. It could control your victron.
This is the first time I've heard of this. Makes sense. I've a small solar electric on my sailboat, a larger one on the house, a small one for a remote shed, and even have a solar electric system to run a small fridge/freezer in my Blazer. I've used nothing but lead due to price and durability. However, this might be an option. Thanks.
greatttt video. we just bought a new to us sailboat and plan on building a new battery bank. i didn't think we could afford a whole bank of lithium. this is great news for us. we will definitely take you up on your generous offer. thanks Clark. love your videos. keep up the good work
yup . i've been doing this for a year. works good . wish this was posted before i gave this a try . i stressed for quite a while to if i was doing something stupid.
Excellent - I need to work the numbers out for myself, but it sounds reasonable, as well as inventive. I am only surprised that I haven't hear of anyone else doing this. Obviously going all lead or all llithium is easiest to think of, but this sounds great. THANKS! Something new to work out. I also want to take the time to think through your BAWG solution.. Thanks again.
Brilliant! You guys are one of my favorite shows. I think you’re doing a wonderful job. Not sure I mentioned it but I put together a 12v hookah based on yours from a video and that video was when I realized you had a TH-cam channel. That hookah works great btw. Side note, I run all Li except lead on the starter. I have 3x100ah at about $3k for the batteries alone. That’s more than a months supply of Kalik beer. Wish you made this video a year ago😂
Thanks Ward. Glad the hookah is working for you. It's a nice piece of gear to have around isn't it? How about sharing our videos with friends on social media. We would appreciate the new viewers.
Thanks so much for the information that has cleared my anxiety. Started with lead but only half the requirement, then a discounted lithium half the capacity as well. Without any choice which to grow then you came along. Thank you so much, at least am experimenting with some confidence.
Glad it helped. This is how I'm doing it now. www.emilyandclarksadventure.com/bbms The BankManager takes hybrid well beyond anything out there especially as far as properly charging LiFePO4 goes. It's simply the only algorithm that does it properly. The ISO just asked me to write a white paper as a base for their new off-grid hybrid battery standard.
Great job explaining it. Looks like this would work well in use, and I suggest a switch to turn off lithium for maintenance. One with a battery disconnect that when connected on 2 runs a resistor to tie batteries together and 1+2 for both together, 1 being lead, and off. That way you can run lithium when checking liquid levels in lead.
Really interesting video! It should be pointed out it will only work with LiFePO type lithium batteries. (We discuss the different types of batteries in one of our videos). Because of the safety risk, this set up is probably best for the rare boater like Clark who has demonstrated that they can keep their lead acid batteries in top condition for 10-15 years. Mixing batteries with different characteristics is usually done using a DC/DC between the two types. One risk to consider is insurance. If there is a claim, would damage be covered?
I understand that a lot of policies won't cover you with any lithium on board, period. I agree with the lifepo4 statement. I'm much to conservative to have any other type of lithium batteries on board my boat and of course they need different charging procedures so it would be hard to get them to play nice.
@@Clarks-Adventure Yes I will 👍🏻 I dont know a lot of people with a boat lifestyle such as you, but there might be other possibilities to use this knowledge. I got a friend with a pretty remote fishing lodge. I think for him this could be quite useful 🙏🏻
Thanks Matze. I appreciate it. I agree that this is a worthy idea for any off grid designer. I'd like to get it out there. I'm talking with a guy who has a great idea for a hybrid specific BMS. Probably do another video on that soon.
Lifepo4 is like sunshine in a bottle for your lead. It has the ability to be quickly charge and slowly replenish the lead. Great way to engineer out the problem of leads slow absorption at the top end by using lithiums ability to quickly take up any sunshine power that is available and then give it up when needed.
Hey Clark, This is the first time I've heard of doing this. I like the concept and wonder if you could explain your "dockside" charging system using shore power and a 120v charger and engine alternator charging or do you charge with solar exclusively?
We are really a solar boat. We have a big alternator but it only runs when we motor and we try not to do that much. We have a 50a ac charger but we never plug into shore side. We are a solar (and sometimes wind) powered boat.
So glad I stumbled onto this post. Now, I wish to become a pat. I'm limited on SS now and living full time in my 34 ft RV motorhome, wishing for a nice big boat around a 40 ftr.. Doubtful that will be a reality. So I have been thinking about this same project. I currently have 400watts of solar and will be adding in another 400 watts in a week or so. Hopefully another 400 before the summer is too far along. I'd even like to add in a little wind in the future, maybe .6kw to 1.2kw of that. It wouldn't be real practical project where I'm at right now as there are a lot of Pine trees and hills around most of me, but there is some wind from the south on occasion without obstruction mostly. But solar is pretty constant during the day from early morning to around 2 except on cloudy days. I'm getting ready to dump a little over a Grand into my system tonight for stuff that will arrive in the next week and then work on more over the summer without the LiFePo4's but those will be coming ASAP along with the BMS systems, I want to have backups in case issues arise, because those aren't that high priced. With combined charge controllers and accessories, this should be doable. If something gives way, I should still have some power even at reduced level to stay in operation. Most of this stuff will be going in the compartment where the Onan was installed, which is coming out soon. I plan on getting one of those little 2kw inverter genny's just in case I need a quick boost to run the 800 watt shore converter if and when needed. A gallon of gas a day or so once in a while isn't all that out of reach.
Hi Brett, That video is a bit old. This is how I'm doing it now. www.emilyandclarksadventure.com/bbms I have some of the black box units with full function I'll sell for $100 off it that helps. And I have a cheaper contactor. Write me at emilyandclarksadventure@gmail.com directly if you are interested. Make sure you read Conrad's article at the bottom of this page. No charger available now charges lithium right. Better to buy mine (that does charge li right) and pick up used chargers and solar controllers that people are selling because they are replacing them with "Li" units.
That's my experimental battery setup for my little macgregor! Works great in my mind, so happy to see it's as wise as I thought! I stacked 18650 to make an independant low draw system li ion. I wanted an electric trolling motor as a backup, and knew my system wasn't up to high draw, and got lead acid to be charged by the li ion.
Li-ion and Lifepo4 are different animals with very different requirements. I've put no thought into doing this with Li-ion. But, very glad it is working for you.
Great information thanks, please don't sell yourself short with the hard sales pitch. You know what, people are likely to support without it. Thanks as always for great content, stay safe.
I have a cal 40 electric with 48 volt 10 kw electric motor . Dc dc charger and 570 watts of solar. I was thinking the same thing but have ordered a battery bank switch. After watching this video I think it may be dangerous to charge on bank one and then switch to both as the could be different SOC . So after watching this I think I’ll just hook them together and it would be like your system . I have 8 t105 Trojan batteries and my lithium is a 48 volt 50 amp hour. I have an electric truck with LTO 72 volts that is run by 600 watts of solar and I never plug it in to shore power. I do think LTO is better option for this however.
You might want to look into my hybrid lithium lead charge controller. It reconnects your banks for you when it sees them at the same voltage. Just what you need. I just got prototypes in. Look at this coming weekends "log" video.
i just love ya'lls ideas and videos . and i will be using them has soon as my wife and I get our boat so you might be hearing from us one day . hope to see ya'll out there in the near future. stay safe and healthy
Came to this conclusion without testing yet but also concluded protection between between batteries would be required for example 150amp fuses depending on maximum draw . I can also see many arguments from many people however ideal and practice versus cost are different
I love your Chanel,you cover so may subjects in a way nobody else does! Thank you. I think I need to binge watch all your content and take notes, and I'm sure I'll have lots of questions.
I'm developing a hybrid lithium lead charge controller that might interest you. It's a fairly simple board that lets the li and pb both charge as they should in our insulations.
Wow. I found this video by searching for this topic, because i have had exactly the same idea. Thinking about discharge curves, i had the same ideas: lead will deliver the high power when needed while lifepo would keep the lead voltage up in the longterm. The only difference is that i didn't tought about connectig them via a resistor, but first chargng them separately, instead i was considering adding fuses between them. I'll check the comment section also.
Yes, this works great but I'm doing it this way now. www.emilyandclarksadventure.com/bbms Seems to solve all the issues automatically and along the way I found that Liis being charged wrong by other charge controllers. This fixes that issue without having to change any of your current charge controllers
Fantastic video thank you. I am struggling with a cheaper brand DC DC charger that gets so hot as soon as I plug in my lead engine battery. I mean hot! So I've bought a victron today to hopefully lower significantly the temp. Fingers crossed victron has addressed this common problem as people are fitting fans to their DC DC array!
I'd return the Victron and use my BankManager. It doesn't get hot because it doesn't waste energy. But most importantly it charges your lithium batteries correctly for a long life! www.emilyandclarksadventure.com/bbms
Thanks Peter. Would you consider sharing this video with your friends on social media? I'd like the new viewers and I'd like to get this idea out there.
You're welcome Matt. If you think your friends might also like this how about sharing the video on social media? We'd really appreciate the new viewers.
I don't know what I just learned about batteries... I feel like I learned a lot! If you ever see a 23 foot sailboat with huge letters on the side that say Floaty Boat, raft up with me because I owe you dinner! ⛵ 🔥
Right now I have my home network (cable modem, WiFi mesh routers, network switches) running directly off of batteries. I have 2x 100 watt solar panels, 1x 20 watt solar panel, and recently added a windmill. I also keep a battery maintainer, a 2 amp, plugged in at all times. Whenever the grid goes down, I still have WiFi. It’ll last about a week on just solar. I’m using two leaf acid batteries. I want to get the proper wires for my windmill. I used 16awg, but I guess I need 10awg or even 8awg. Ultimately, supporting myself completely off grid is the goal, but it’s so nice to have the grid to keep it topped of for the maybe 7-14 days of the year where their is neither sun or wind. All I need now is to get Starlink, by Tesla, Elon Musks internet service, and I should never lose access to the internet, or pay a monthly fee for the energy to power it.
Clark thank you so much for this. I have been contemplating just how to integrate some lithium into my system... you have thought 'outside the box' on this one and given some awesome info here. Million thanks.
I'm just finishing up development on a circuit that will charge both types of batteries exactly as they would like to be charged. Should be available soon
The marriage between lead. And lithium idea is brilliant ! Wow 😲 I’m a electrician and electronic tech , and never thought about that , but ya ! Makes perfect sense, but yes be very careful connecting batteries together, in parallel, the voltages must match or 😵 trouble. Great explanation! ( subbed) 👍
You covered pretty much everything there and it all makes loads of sense. The only thing I want to point out is that this setup may make the lithium batteries fail. It is not a mid-voltage issue, your voltages all make sense. The thing is that voltage may be too in the middle. Most lithium battery BMS systems will balance their cells at like 14.6 volts or like around 12 volts....So they top or bottom balance. If you spend too much time in the middle...which is best for the battery longevity in terms of voltage....it may mean the cells never balance. Now this would be different from battery manufacturer to manufacturer...and BMS to BMS...You said that you push the voltage up to 14.0 volts....if you actually are using Battleborn as your diagrams suggest. They will die. Why because Battleborn cells balance at a minimum of 14.2 volts for quite a while. 14.0 volts is too little for a top charge. Now likely you do put in higher voltages than 14.0v while charging, so your cells likely do balance a little while that is going on...the thing is passive balancers take days to do their job sometimes as the current is soooooo verrrrrry looooooow. Likely your cells are very slowly getting out of balance....it could be worse...but it will likely get out of hand at some point.
That's good information. I'll crank them up to 14.2 now and again. Kinda want to do that for the lead anyway. Though staying below 14.1 I probably could go a long time before any imbalance became problematic. Whatever kind of follow up video I do will include your idea. Thanks Allyn. I'm working with another boater just now on a specialized BMS for mixing lead with lifepo4. Stay tuned for another video. Best feature is it will let the lead charge first then charge the li. Still working out details.
What I'm also concerned with is holding the LI up to 14 too long. What do you think about that? It's not an issue with my video proposal exactly, more how my personal charge controllers function.
@@Clarks-Adventure Well...most lead acid charges at 14.4ish volts....so running voltages there abouts isn't actually an issue if you don't cook the lead acid or the lithium...I thought top voltage and the "eqalization" voltage according to Victron is 14.4 volts for the Battleborn. You are kinda in between a rock and a hard place. Every once in a while you should take your Li up to pretty close to a full charge so the BMS or in some cases the cells themselves don't "go crazy" too....You could manually reconnect to the lead-acid at just the right time in the charge discharge cycle so those two won't pull too much energy. Maybe a circuit that sees a balance occurring and a contactor...Unfortunately holding the Li above 14. for some extended period is the best option. If you don't do it a lot, it shouldn't take too much of a life cycle off in the long run, and sure beats having a necessary cell failing internally.
You're welcome. You should consider one of these. www.emilyandclarksadventure.com/bbms Since this video I've realized that no charge controller is charging lithium "correctly" and just connecting the batteries can leave lead not fully charged. This device takes care of your individual battery banks.
Hey! Nice thinking! I've been thinking along the same lines but got a bit stuck in the float voltage difference problem. I was thinking about having two-way diodes and what not to get a stable voltage drop between the banks to compensate but it felt so complicated. Your idea to just let it float charge the lead bank is clever - it should be just fine. One thing scared me a bit, which I should tell you about. If you connect them as you say, and then, for some unforeseen reason the BMS turns the lithium batteries off. Let's say you bridge the starter and house battery banks or something and you charge it to 14.7V. After the BMS is off the lead acid batteries will start to discharge... at some point, all of a sudden, the BMS turns on again. Then you have an issue. A lot of power will run over those wires as you point out in the video with unbalanced voltages. So I'd suggest you just put a fuse between the banks. Connect every consumer and supplier to the lead side and fuse off the BMS and lithium with like 150A or similar, depending on the use. It might save you from a fire. You might already have a fuse, then this comment hopefully help some other boater who just connects them together. Feel free to send me a message the day that fuse is blown and you don't know why. This is in actually a general problem with all lithium batteries which has individual BMS'es. When they switch on there is potentially a huge current rushing between the batteries. I usually recommend a supplier with a system wide BMS shutdown instead of per-battery partly for this reason.
I just developed a device that solves all this. It breaks the contact to the li when fully charged and let's the lead finish it's charge cycle. It only reconnects when the voltage of both systems are close. Solves about everything that I can think of. Video to come. Subscribe.
Interesting video, I'm seeing lots of folks mixing battery chemistries, though instead of getting the battery that's suited to the load like you are, most of them are simply keeping a load on the alternator if the BMS drops the Li battery out of the loop. I'm in the process of replacing the battery bank in my trawler. We had flooded cells for house and starter bank, and I wanted to get rid of them. I was sick of checking levels, corrosion and such. The wood under the batteries had deteriorated from the acid and the batteries were aging out anyway. Time to upgrade. I've been using LiFePO4 in my RV for about 5 years and have worked with both drop-ins and custom prismatic packs. After looking around, DIY Lithium batteries are easy to build, cells and BMS are readily available and can be built for about the price of AGM batteries, if you've got the space to work and the few tools needed to do it. If you DIY, they're about a third the cost of good drop-ins like Battle Born. Our old house bank ran our anchor puller ( ~150A ) and bow thruster (~350A), plus they were available to be combined with the starting bank to start the main if needed. I could have moved the big loads to the starter bank, but I didn't want to lose the ability of the house bank to start the main if called upon, so I wanted a bank capable of big current. I chose AGM batteries for the replacement starter bank. Simple, powerful, no maintenance. Done. We use a lot of energy and enlarging the house bank would also be beneficial to our cruising way of life, at this price it seemed like a no brainer. For the house bank, I bought sixteen 310Ah LiFePO4 cells and made four 310Ah@12v batteries out of them, each with a 200A (400A for 5 sec ) continuous BMS, giving me 800A continuous. Plenty to start the main ( I've been starting it with a 400A class T fuse inline forever ), run the bow thruster, pull the anchor or heat dinner. Each battery fit in an inexpensive plastic gropu 27 battery box with the BMS mounted on top for cooling, though I don't expect that to be needed. I got rid of about 200lbs of weight and moved the batteries to a better, cooler location for longer life. My total cost for the batteries is about $2600 for 1240Ah@12v, including the parts for the case. Anyone building them with my method will need a few hand tools, a good voltmeter and a variable power supply, I got what seems like a pretty good one from Amazon for $75. In the end, if I had replaced my 6V house batteries with AGM's, I probably would have spent close to $1500 and gotten about half the capacity I now have. If I could have found the space to put twelve 6v batteries and had been OK with another 400lbs or so of batteries, I could have matched the energy storage of my four batteries ( in the same footprint as four 6V ), but would have spent about $3k. I have bluetooth connectivity into each BMS and can see the individudal cell voltages, so if there's an issue I can hopefully find it. This technology is moving pretty fast and prices have come down a LOT. I kept some lead on board as a starting/backup bank, but we're getting closer and closer to the day when that won't be needed, either. Admittedly, I don't have a lot of experience with these cells or the BMS, so it's kind of an experiment to see how this works out longer term, but I guess, so is paralleling LiFePO4 and AGM. Ordering direct from China can have some downsides and not everyone has had the best experience. Will my cells hold up for 3k cycles? Will my BMS be reliable? I'll start to know the answer in a few years, but so far I'm impressed with how well the cells have stayed in balance when I capacity tested the batteries ( all tested well and within
Looks like you should do your own video. What happens if you get hit by lightning? BMSs can fail. But it looks like you have the expertise to just monitor them manually
@@Clarks-Adventure We're coastal, so we're not going to be far offshore, but we have made 10 hour passages. If we completely lost the entire LiFePO4 bank, I'd run down and use the on/off/combine switch to combine the banks and the boat would run off the 180 Ah ( two group 27 AGM ) starting bank. Our engine is a Lehman with entirely mechanical injection, so that would continue operating after a strike and as a trawler, it would already have been running if we were under way. Assuming the alternator survived, we'd be fine running on the AGMs for an extended period of time. If the alternator died and the generator and chargers had died as well, we could probably run for another 5-6 hours or more with the AGM's powering a limited number of items. We keep a charged phone as a backup nav unit wrapped in aluminum foil, so we can navigate for an extended time ( we have several portable battery packs ) even if the entire boat had no power.
@@Clarks-Adventure Oh, and I don't see much of the point in doing my own video since Will Prowse is where I got my ideas and he makes great videos. My case design might be worth showing a bit, since it's cheap and easy to build and would work well for marine applications.
I hadn't thought about it, but it wouldn't take more than about 30 minutes to rewire all four batteries to bypass the BMS and continue to use the batteries without protections. Normally, the BMS isn't really doing much other than watching over the parameters to make sure nothing is too high or low and doing a tiny bit of cell balancing. In 5 years of using Lithium in my RV's, I've only had one incidence of the BMS disconnecting the batteries, which has never repeated itself. I have had disconnect switches melt because of the charging load with solar, inverter/charger and alternator all charging at once at >160A. The batteries were fine.
Very interesting video. Well done! I had plans to exchange from AGM to Lithium, but after your video I made up my mind and I will definitely dig into this a bit more and probably ask your advice on Patreon.Thank you!
great video! happy i found your channel. I've been brainstorming how I could add more wattage to my bank with lithium, to supplement instead of replacing my existing lead batteries. Thank you!
Clark, thank you so very much for this outstanding video instruction and information. I am installing a lithium iron battery into.my.hoise battery banks on SV Medicinal. Your guidance will help me avoid any issues and will allow me to take full advantage of the combined energy output! Hope you and Emily are well! Hope to see you guys in the near future!
Doesn't exist yet. I think it will be sold by the same company that manufactures my AC system. Best thing now is ho to the AC video description and fill out the survey. If you answer yes to the bank manager question you will get an email when we have something. Strangely now that AC is mostly done I'm finishing the software for the bank manager today. Just re-set up my lab and booted my computer. What timing!
I'm running my 3.2Kw solar system with 24V tall tubular battery pack. I have 2 lead acid batteries (12V, 185ah each) in series. Selfmade 24V lithium battery pack of 200ah capacity... I'm using both packs in parallel... It's giving too much satisfying results...
I have two comments. Your system has the potential to charge your Li at more than .5C. That's hard on your batteries you might want to add more Li. And that's an old video. This is a better way to do things. In fact it's the best way to charge LiFePO4 available. www.emilyandclarksadventure.com/bbms
Wow, this really makes so much sense. When he talked about linking them together, I thought he would just say make sure your lead has a higher voltage than the lithium, would that not be ok.
I'm doing it this way now. www.emilyandclarksadventure.com/bbms Lots of reasons this is better. Mostly it charges the lead and lithium properly. No other regulator seems to.
One big caveat is cold weather. The LiFePO bms will disconnect if trying to charge in below freezing temps. Then the batteries can get out of sync that way.
@@Clarks-Adventure thank you for that . To be accurate I bought a Lagoon 40 at a boat show in 2019 through a charter management deal to get me on the property / boat ladder. The boat was delayed due to covid but at least I kept the 2019 price as everything has gone up. I can't install anything until I get the boat back in 2028 , so I'm doing lots of sailing and signing up for courses - mechanical and electrical to try and understand the basics . Your videos are great even though I have no idea what you mean at times ! My girlfriend says you look 15 years younger without a beard by the way 🙂.
I don't recommend this anymore This is much better. www.emilyandclarksadventure.com/bbms It treats your lithium correctly. Other regulators that charge to a set voltage all can cause low current overcharging that leads to cell death.
Wow! I've been working with Lithium for about 5 years now, building astronomy rigs for mobile DC systems. I never realized you could mix with lead acid, this explanation was terrific and I love your strategy. I've been watching you for some time, thank you for everything! I took up sailing this past year, and have been considering buying an older sailboat and refitting myself, and I was going to go pure lithium - but I love the idea of cheaper lead acid. I think for the pros of lead acid - the extra weight for ballast? Thanks again - I'd love to hear about your AC setup though - with kick and overall amp run - you would need a significant amount of batteries for multi-hour AC no? Some actual numbers of what you burn in amps per day with AC would be super useful thank you.
Thanks Charles. You aren't alone in wanting to know about my AC. It runs all night in the tropics easily off 2 100amp lifepo4s. It's quite adjustable. As I have it set up it draws about 15 amps at 12 volts and once it gets the cabin cooled it runs about 1/4 of the time through the night. Video is coming but I had to explain how to power it first. Some have already signed up to my Patreon to get help building their own. I'm currently writing a video to go with this one. The next is why it's good to include some lead in your system even if you are going all lithium.
I've had this idea for a few years. I was just planning on having solar that goes through charger to lithium, and then a charger from lithium to lead acid, with the load connected to the lead acid. Lithium becomes a no sun float charger. For my boat design I am using 3000kg of SLA (40X270ah (74kg)130kwh) as ballast and battery, and was going to use 30kwh of lithium (100% rating) The system is designed to float the lithium around 50% and SLA at 100%. With about 15-20kWh of solar and calculated usage, the lead acids should not get discharged more than 10% for normal usage and an expected life span of 20 years. I hadn't seen anyone do this, but thought it was a good idea. With the combination of solar, wind, and wave energy I would never need to charge from port or generators. Also enough power for an onboard greenhouse which is a must; something I have also seen nothing of on boats.
That's basically what I do with the BankManager. You don't need a dc-dc charger to go from li to lead as the li will float the Pb right in the Pb sweet spot of 13.2v. Your proposal still has the Pb cycling a bit more then mine unless your DC-DC is up to max used amps and of course the DC-DC burns power into heat. I see you can understand this. I see a lot of my early ideas in your comments. I'm confident you will see that the BankManager approach has a lot of benefits. Especially once you see the problem that exists with current chargers, the low current overcharge issues, and see how the BankManager fixes it. You are just the kind of person I want to install one as you will be equipped to explain it to others .
@@Clarks-Adventure Your idea may be better than mine. I still have many aspects to figure out. How often the Pb bank would cycle would really depend on size of lithium bank, external input and draw. Initial calculations were with a gyro stabiliser, but may not install. I'm still a few years off building a boat. The design is around 25 metres long and 5 metre beam, but I can't even find berths for a boat that long near where I live (Melbourne) that are secure. Australia has so much coast line, but we have little infrastructure for boats. You may have said already, but how large is your battery bank?
This works for virtually any size. I have a 48v hotel interested. I have 1400ah of AGM and 200ah of Lifepo4. That's a lot of lead, I had it before the li.
Wow. Timely for me as I am just setting up my charging system on our new-to-us boat. This took some time and thought. Nice job Clark. So you are setting your solar charge controller to the lithium setting as well as your engine charging system and letting lithium batteries manage the lead bank recharging by pretending that the lead bank is just a load like a big light bulb. The lead acts as a buffer for heavy loads and sun-less days so to speak. Is that right? The cyclical deep discharge-charge-discharge-charge cycling is borne by the lithium, which can do that all day. Nice. If the system were to totally discharge totally it would seem that the BMS would lose its mind when charging in parallel with the lead bank and you'd have to disconnect everything and start from scratch. My guess is that this has to be avoided by sizing the lithium bank correctly in the first place. Hmmm. Another question...So do you keep your start battery (lead) discrete, or just let all the batteries play together?
Close, but not exactly. I really can't keep up with questions individually here. I'll make another video or two on this eventually. Remember my offer to do one on one help over patreon.com if you want more in-depth or timely help.
Love your channel, I learned so much from you guys. We just started our channel. We are completely new and so grateful for all the info and inspiration the two of you give.
Since I did this video I've found a better way to do this. www.emilyandclarksadventure.com/bbms Charges the lead fully and seems to be the only way to not cause "low current overcharge" of the lithium.
Hey cool video! I made the same experience with lead acid batteries. The 13.2 Volt level save the batteries from sulfating the plates. Very cool idea to combine them with Lithium batteries. I would keep the starter batterie separated but charged by the bank with a small step up converter. For emergency I would install a set of supercapacitors. You can load them with a step up converter even from a very low power source and start the engine with a nearly discharged batterie or via the solar panel. Thanks for sharing this video! Have you heared about the guys from a boat called "Chuffed", the solo sailing girl on her boat "Karl" or the adventures of "SV Delos"?
@@Clarks-Adventure Very interesting. I have a ton of questions but a year or so from starting the project. E&Cadventure is at the top of the lithium refit list. TY and GL, I hope this top shelf engineering is very rewarding. You deserve it.
Can't believe I've only just subscribed. Super useful channel. I have an AGM LIfePo combo. AGM for the start battery and bow thruster and lithium for everything else. They are not directly connected (although I can do it manually if say the AGM needs a top up), but they are connected to the same DC to DC charger. With 120 AH AGM and 300 AH lithium I'm finding this is plenty for our needs, but we don't of course have air conditioning. A good solar array and wind gen plus a 2000 watt inverter complete the picture. I'm also thinking generators are no longer necessary these days, although it might make sense having a small petrol one stored away for occasional use.
I'm finishing up a device called a bank manager that will let you remove your dc-dc and still recharge both your banks just the way they need to be charged with no loss of energy. Got picked up by a company that will sell them soon. Glad you are enjoying our videos. Welcome aboard.
Great video Clark, and a great idea too. Also very nice you are willing to help people with their setups. I will be sharing this video with a friend of mine, which also means I will probably end up helping him do it if he decides too. But I enjoy this stuff too. Thanks for sharing.
Excellent presentation, and a very good point you make here. I am working on a 24V lithium only bank, to power just the inverter. I don't like the idea that the BMS can decide that I don' t need my AIS and Chartplotter right now, because one cell is out of ballance :-) This way I can support my 12V system, and know that the BMS can't mess me up! BTW, I already converted to Induction cooking. I modified two 800Watt chafing dish heaters so they will go up to 180 degerees celcius. What a great time to live onboard!
Thanks, That is another good reason to do my hybrid thing. In a couple of hours I'll be releasing another hybrid video that talks about that kind of issue. Sort of the opposite of the first - why I think you should always carry some lead batteries even if you go mostly lithium. th-cam.com/video/sqT27KbxRec/w-d-xo.html Since you went split voltage I assume you will be using a buck/boost (dc-dc charger) converter to charge one if the banks?
@@Clarks-Adventure I will use the 12v inverter to charge the 24v inverter/charger. Bit inefficient but half way in the project, I have to be careful with my spending:-) The plan was to get a well regulated 24v alternator. All the puleys and mounting points are already there. Using your engine as generator makes more sense with lithium too.
Just had an idea. If you used a boost converter set at like 28.4v or whatever to charge your lithiums and added a voltage sensitive switch to turn it off once it hits top voltage and on again when there is charge and voltage goes low or a clock says it's time. You would have a more efficient cross charger with low cost.
A video showing how you balance the amperage using the resistor would be super helpful in building my confidence before making a big change to my system! Thanks for all you do.
I have since developed a device called a bank manager that will be available for sale soon. It takes care of all that and makes sure that both types of batteries charge properly. You don't have to install special li charge controllers so it saves a bunch of money. Go to the air conditioner video and fill in the survey in the description to be kept informed.
@@Clarks-Adventure I guess you mean "charge the batteries properly" NOT "charge the batteries probably" These auto correct spelling innovation is often a step back not forward! André
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Hey, very cool video. Nice pictures too. Fun to watch.
How much current feeds into the lead acid to trickle charge them at high SOC? Have you tracked what happens with a shunt between your batteries over a typical night?
At low SOC, it would seem the lead acid is reducing the performance of your system. Considering that the LiFePO4 wants to keep the voltage high, you couldn't use most of the capacity of your lead bank. I suppose the bms could disconnect and reconnect, but the differing internal resistances disconnecting and reconnecting seem a bit scary. I suppose the lead acid does act as a buffer. Hmmm. I would have to see how they feed each other over a cycle. That is difficult to do without a data logging device. Have you done that yet?
I see, so small lithium battery, big lead bank. Hmm I suppose that is attractive for a marine system.
Have you done a full capacity test? How deeply do you discharge your bank? If you keep this bank at high SOC, and none of the cells short, it would probably work fine.
Good point about setting absorption at 14V. Very true.
The prices of lifepo4 are dropping quickly. I built a 280Ah 12V pack for $580 this week. That is cheaper than high quality lead acid, if coulombic efficiency and usable capacity are taken into consideration.
You should try LTO. LiFePO4 is touchy, but that is only if you do not have a BMS. LTO would destroy every downside of LiFePO4 you mentioned. You can discharge at 10C rate! You can start any size engine with a modest size pack. You would love them I bet. Everything you stated in this video screams LTO. I did try paralleling LTO and LiFePO4 some years ago, and it was horrible. My capacity test results were awful. LTO has a wider voltage range, and more linear. And my test results were awful because of it. The cells would feed each other constantly. Very inefficient.
Trickle charging lead acid all night with lithium seems very inefficient. I suppose if your loads are small, you can do it. Just that difference in voltage at various SOC makes me cringe.
But yeah, do you have any data logged on how the batteries feed each other during a full cycle?? I would love to see it.
Thanks for writing. I've been subscribed to your channel for quite some time now and when I meet sailors with questions about lithium I send them your way first. You do a great channel with reliable information and a very approachable style.
I have been living off sun and wind for over 20 years on this boat traveling around the warm parts of the world.
I started this hybrid system just over a year and a half ago. I already had a huge (1500ah) agm lead bank in great condition but I wanted to add an air conditioner I was designing and didn't want to cycle the lead that much. The life cycle loss and just plain inefficiencies of lead made that not a great idea. I was first going to set up some kind of DC/DC charge system but soon fell on this idea. I must say it has been working extremely well.
So my system consists of just over 1400ah of AGM L-16 sized main house batteries. There is also a small agm and a flooded lead starter battery tied in through a voltage sensitive relay. I added two Battleborn LiFePO4 batteries during my last big refit in the US.
With the "rest" voltage differences this system uses most of the power in the Li bank first before dipping into the lead. That is what makes this work so well. Also, as you pointed out, the Lead has a relatively high internal resistance. This actually helps a lot with keeping everything safe.
On a typical night even with the use of air conditioning we don't deplete the lithium bank and usually wake to a system voltage of over 13.0 volts. At this state the lead is still fully charged. So it is seldom that the lead goes into low state of charge. It happens only when we have had days without sun or wind.
I was surprised to find that the lead bank uses 0.5amps to hold itself at 13.2v. So if we have, say, 14 hours without charging that wastes 7ah of power. That is less then what I would loose through inefficiencies charging and discharging a pure lead bank so I'm ahead of the game ah wise already.
When we go several days without sun or enough wind we do dip into the lead. During this time the Li still is very helpful. Lead will not take a charge as fast as Li and often one finds they waste power just regulating it away. With this set up the Li acts as a capacitor in a way accepting all the power and trickling it into the lead later if necessary. Not perfectly efficient but this is a rare occurrence. Over a few days the lead and Li get fully charged and all is well again.
Voyaging boats are a bit different then houses and campers. When things fail we often can't go to the shop and get a replacement. And we rely on our power a bit more heavily. Not only do we have lighting and refrigeration but engine starting autopilot and navigation are hard to live without. I've been hit by lightning several times (th-cam.com/video/PurMG7KHdW4/w-d-xo.html) I'm concerned what that would do to a BMS. So having lead on board feels safer. Also, there are a LOT of boats that aren't going to Li until they need to replace there current lead. After all the batteries you already have are free.
You might also find this video interesting (th-cam.com/video/sqT27KbxRec/w-d-xo.html) It's sort of the other side of the coin, why you might actually want to add a Lead battery to your Lithium bank.
After doing these videos a couple of things have happened. One is my flooded starter battery failed in a dead short manor. It took a while for me to notice since all we had as a symptom was a slowly falling voltage and (I wish I would have noticed this earlier) our water from the taps was getting warmer due to the filters being near the failing battery. There were no real dangers. The system depleted it's self into the bad battery, final system voltage got to 12.6v. I just had to remove the bad battery from the system and start my generator for the first time in years to boost everything back up since we were having a long rainy spell at the time.
The other thing that happened turned out even more interesting. Many people questioned how I was charging my batteries. Just charging them together isn't optimum and it got me thinking - what would be perfect? Well, I have since developed a hybrid lithium charge controller. It's at the breadboard stage now but working fine. I just got the components this week so I can solder up the finished model. This device does two things. It disconnects the Lithium part of the bank once they are fully charged so the Lead can charge fully on it's own. And, possibly more importantly, it reconnects the Lithium when both sides of the bank are at the same voltage so there is no large inrush current. This is the key that makes this idea work for more people. I'd like the chance to chat with you about this. Would you be up for a phone call sometime? I have a US number and good data connections here in the Dominican Republic. I'll send you a personal message on the email listed on your website.
I expect to do a video on my charge controller soon to finish up this series. I will make the design publicly available and might even do a short production run and sell the units if I find someone on land that is interested to be involved as I can't ship things from the boat especially when I'm voyaging.
@@Clarks-Adventure oh hey!! Thank you and yeah sounds great, email me anytime 😁👍
@@Clarks-Adventure good points you make about voyage boats. And the lighting and bms. That would surely fry the fets if a long conductor in your system accumulated enough charge to cause voltage spike. Would be fun to measure that. Wow, so many factors in marine systems. Very interesting
@@Clarks-Adventure I would be interested in your beta release of the charge controller. Like many other RVers who have a limited existing system (2x12v FLA batts with 2000w modified sine wave inverter/charger) I am looking to add LiFePO4 batteries to augment my capacity - but I would like to charge those batteries as quickly as possible while running the generator or connected to shore power. I know that's not in your current wheelhouse... but if you have a good idea - I'm all ears.
That's exactly what this device is for. Stay tuned.
Hi all,
I'm glad so many people are finding this interesting. I'm enjoying all the comments and it seems like you'd like another video or two on the subject.
Problem is I just can't keep up with individual technical questions over comments. This subject is a bit complex and relies on a certain knowledge of how electricity works and flows. It seems obvious from the questions that many of you have some misunderstandings in this area. I just can't do a complete answer to your questions and know I'm not adding to the confusion while typing on my little phone screen.
My offer to do detailed help over patreon stands. I'll answer simple questions at most levels and at our "dream believers" level I'll do my best to do a proper job with individual analysis of your needs and education over the phone.
Also,
I had an idea yesterday for a device. Talked to a really talented EE friend back in the states. I think we will make them for sale.
It's a lithium battery charger that is made especially for li/lead hybrid systems. Not a dc/dc converter. Allows your existing lead chargers and regulators to charge the li part exactly like it wants to be charged but still charge the lead as it needs. No trade-offs.
Do you think people would want such a device?
Your entire video I was trying figure out the best way to charge this system. I actually have a relatively small setup where I am trying to develop systems that are ideal for colder climates that limited amounts of sun. I am currently using 2 100Ah lead and 4 100Ah and a MPPT charge controller and DC-DC charger.
Absolutely would be interested in a li/lead hybrid charger!
Clark, I'm guessing there may be interest but in my opinion, very few will be willing to pay.
The typical boater will not do anything unless there is a need. Take me for example, the bank on the boat we purchased was AGM of a unknown age however the PO seems to remember having them replaced about 12 years ago. Last spring they where flat and I was unable to bring them back so investigation of the replacement type began. I do not assert that I am an expert in the battery field but based on my circumstances, the choice was relatively easy. Our boat came with a quality 30 amp marine smart charger and a high output alternator setup for AGM. I am also some what of a thrifty individual and only plan on owning the boat for a maximum of five years. Those circumstances pushed me to AGM as the replacement as lithium ROI comes from the long term. Our new three house bank batteries come in under 300 ah and we run the normal anchor out/navigation loads plus a 24/7 Iceco portable 12 vdc compressor freezer ( I like ice cream, seafood and meat). The battery bank (from Battery Plus) has a three year replacement warrenty. I am able to run the original ice box refrigeration but not continuously but it works for us. Adding solar this coming season (probably 400 watts max) which may help with the built in frig run time. We do have a slip but typically anchor out three to four nights a week and will be traveling through the Great Lakes and East Coast and beyond once we feel comfortable traveling again.
OK so I fall into the lazy/cheap group as noted above.
The other obstacle you will have to consider is the battery vendors themselves, pretty sure you have difficulty finding any of them who will warrenty mixed types. The last potential obstacle I anticipate, is it has to meet code so insurance companies cover losses.
Anyway, appreciate the opportunity to respond to your question.
Heck yes!!!
"Maybe", I'd need a small version for tent and motorcycle.
The engineers, who comprise but a tiny fraction of the population, have built the world we live in. May God bless and protect the engineers.
Thank You
Thank you ! Amen
Thank you! You're giving us too much credit.
Thanks for posting a link to my Article :)
It is early days since I made my Hybrid Lithium-Lead (more precisely Hybrid LiFePO4-PbC) Bank but from the analysis (not just the three days used for the charting in the writeup but continuous 24/7 minute-by-minute data logging over many charge and discharge cycles), I am convinced the theories convert to a practical setup with some distinct advantages over pure lead OR pure lithium.
I've thought about this too before, it's what we do with hard drives in large storage systems.
Solid state disks do all the day to day work, but mechanical disks do all the long term heavy lifting.
Glad someone did more digging on the subject! Great video Clark. 👌🏼
This makes so much sense. Most people so far knock either one or the other, but what you say makes so much sense. As I’ve said many times. I never watch an Emily and Clark episode that I don’t learn something. I hope to be building a system in the future, and this is fantastic insight and information. Isn’t it interesting how having an open mind can lead to better understanding.
Thanks Bob.
When you get close talk to me. I'm working with a guy on a really cool BMS that is all about hybrid packs.
I have been putting together a big system on my boat and had this idea for a different reason. Lithium can take a charge faster than lead, and lead benefits from being float charged to get from 85-90% up to 100%, but it takes a LONG time. So my idea was charge everything until the lead hits 80% (at which time the Lithium should be fully charged). Then shut down the generator and have the lithium - through a battery to battery charger like the Sterling or Victron- to bring the lead up to max over the next few hours. Now you have a full lead bank, but a lower lithium bank. To your point, you can now use the lead to supplement the lithium through a smart battery connect until the lead hits 50%. At that point the lithium can go a little longer until its at 30%. At that point you have to re-charge. Main point is you can reduce your charge time as the charge acceptance rate of the lithium is so much higher than the lead. This assumes no solar. Of course, if you have solar, charge time is even lower as the solar - or wind - has reduced discharge. We both agree, reducing generator run time is the goal! Great idea and great video.
watched this video years ago; watching it again today ! Thank you.
Have you seen my BankManager. That's a much better way to do it.
I really appreciate your channel. I’m a photographer going “digital nomad” living in a sailboat outside of Stockholm. I’m following the Dream but haven’t a clue about living in a boat, thank you so much for these absolutely down to Earth tips🙏
Clark, I know this was 3 years ago and you have subsequently updated and improved with the development of your Bank Manager. But this has to be one of the most influential videos on TH-cam - I've seen it cited all over the place and it has clearly influenced a lot of people. After about a year of internal debate with myself I decided recently to go down this route pretty much as you laid out here and it feels like a complete game changer. Heading out on the boat for a month next week so that will be the real tell! Have not installed a Bank Manager (yet) because the protections provided by the BMS in my new Renogy PRO LiFePo4 battery together with the ability to control charging profiles leads me to believe I don't need it. But time, again, will tell!
But thank you for your contributions to the sailing community which go far beyond this one video.
You are very welcome.
Yes the ISO contacted me and asked me to write the bases for their hybrid battery standard because of this video.
I do very much disagree with the level of protection you are getting from your BMS but we all get to do what we want. I believe in freedom.
But I do feel bad for your batteries, they deserve a longer life than 3 to 6 years. :)
Is there a video about your home grown AC? This is the most informative sailing channel on TH-cam!!!!! Incredible!
Thanks. That's so nice to hear.
Please tell your friends and share our video links on social media, we could use the views. We aren't getting that many. I'm beginning to understand people don't care about informative.
The video on the air-conditioning system will likely be the next technical video we do. Emily just got out of the hospital today so I'm not sure of our schedule.
@@Clarks-Adventure best wishes for a speedy recovery Emily. I am looking forward to seeing the A/C design and build video too.
started with vhf, now i am addicted .. i have a red jacket, 17fy its my learner vessel. i live in whyalla so i have flat waters to learn, and teach my son.. we watch your vids every time he asks a question, to learn together
thanks so much for your share
Makes great sense, gonna try this out in a small off grid studio that I have
Thanks for sharing, best video I’ve seen on this topic.
Have you seen this?
www.emilyandclarksadventure.com/bbms
I have not lol, thanks🎉 glad for the informative explanation in this video anyhow
Clark I have been,researching the whole agm / lithium battery issue for a couple of months you just saved my 500 amps of agm and me about 2k on lithium I think 150amps of lithium will be fine but now I need to wait for your A/C video before I make my decision.,like the way you think, thankyou you for sharing
great info . i found this info on a battery forum about a year ago . and have a van solar set up with
3 x 100ah lifepo4's in a string . and use a manual isolator linking to the start battery , therefore intern also the alternator . i use the lead combined for big inverter loads like A/C as well .
i've been throwing that switch sporadically for around a year now . i have the victron smart shunt and can tell you -- with the start battery at 12.5v and the lithiums at 14.2v it only shifts a couple hundred watts for a few seconds .and ramps down quickly ,
i have never burned out a switch or a wire . or anything . so i'm going to say in this respect to this ,you are being over pedantic with the volt matching .great video though . i had to search hard for this info 12 months ago . so big ups for the added knowledge .
it's true they work great together .
You are being saved by the fact you don't have much of a lead bank. Lead has high resistance but if you put a lot of it in parallel it can really suck in the amps. For example my boat has 1500ah if lead.
But glad to hear your data. Thanks. It helps me, especially when I start selling these controllers to vans and small boats.
You might still like one of these circuits. Just so you can forget throwing the switch.
My controller actions an external contactor. It could control your victron.
This is the first time I've heard of this. Makes sense. I've a small solar electric on my sailboat, a larger one on the house, a small one for a remote shed, and even have a solar electric system to run a small fridge/freezer in my Blazer. I've used nothing but lead due to price and durability. However, this might be an option. Thanks.
Watching this video makes our conversation make so much more sense now... Discussion never equalizing etc. ;)
greatttt video. we just bought a new to us sailboat and plan on building a new battery bank. i didn't think we could afford a whole bank of lithium. this is great news for us. we will definitely take you up on your generous offer. thanks Clark. love your videos. keep up the good work
Cool, looking forward to chatting with you.
Virgil, Would you consider sharing this video with your friends on social media?
yup . i've been doing this for a year. works good . wish this was posted before i gave this a try . i stressed for quite a while to if i was doing something stupid.
Thanks for the support Richard.
Love your channel Clark. I'm really enjoying learning from your technical experience and life views. All the best for you!
Thanks Hezi. Please consider sharing our videos with your friends on social media. We would appreciate the new viewers.
The best I have ever seen, thank you.
This is a fairly old video.
We do it this way now. www.emilyandclarksadventure.com/bbms
Excellent - I need to work the numbers out for myself, but it sounds reasonable, as well as inventive. I am only surprised that I haven't hear of anyone else doing this. Obviously going all lead or all llithium is easiest to think of, but this sounds great. THANKS! Something new to work out. I also want to take the time to think through your BAWG solution.. Thanks again.
Thanks Stephen. If it checks out how about sharing this video with your friends on social media?
@@Clarks-Adventure You can count on it!
I just bought 2x140ah agms to add to my original 105ah agm and now I will use this information to add lipo in the future, thanks.
Brilliant! You guys are one of my favorite shows. I think you’re doing a wonderful job. Not sure I mentioned it but I put together a 12v hookah based on yours from a video and that video was when I realized you had a TH-cam channel. That hookah works great btw. Side note, I run all Li except lead on the starter. I have 3x100ah at about $3k for the batteries alone. That’s more than a months supply of Kalik beer. Wish you made this video a year ago😂
Thanks Ward. Glad the hookah is working for you. It's a nice piece of gear to have around isn't it?
How about sharing our videos with friends on social media. We would appreciate the new viewers.
Let us know how this hybrid setup works out in the long run, thanks again for sharing
It's been going for a year and a half so far but stay tuned.
Thanks so much for the information that has cleared my anxiety. Started with lead but only half the requirement, then a discounted lithium half the capacity as well. Without any choice which to grow then you came along. Thank you so much, at least am experimenting with some confidence.
Glad it helped.
This is how I'm doing it now. www.emilyandclarksadventure.com/bbms
The BankManager takes hybrid well beyond anything out there especially as far as properly charging LiFePO4 goes. It's simply the only algorithm that does it properly.
The ISO just asked me to write a white paper as a base for their new off-grid hybrid battery standard.
Clark always thinks outside the box!
Thanks Jeep. Would you consider sharing this video with your friends on social media?
Great job explaining it. Looks like this would work well in use, and I suggest a switch to turn off lithium for maintenance. One with a battery disconnect that when connected on 2 runs a resistor to tie batteries together and 1+2 for both together, 1 being lead, and off. That way you can run lithium when checking liquid levels in lead.
Sure that would work. I'm making a device that will solve this and other hybrid issues. I mention this in the other lithium video.
Really interesting video! It should be pointed out it will only work with LiFePO type lithium batteries. (We discuss the different types of batteries in one of our videos). Because of the safety risk, this set up is probably best for the rare boater like Clark who has demonstrated that they can keep their lead acid batteries in top condition for 10-15 years. Mixing batteries with different characteristics is usually done using a DC/DC between the two types.
One risk to consider is insurance. If there is a claim, would damage be covered?
I understand that a lot of policies won't cover you with any lithium on board, period.
I agree with the lifepo4 statement. I'm much to conservative to have any other type of lithium batteries on board my boat and of course they need different charging procedures so it would be hard to get them to play nice.
Very cool. It seemed like a logical and reasonable idea. It is nice to see someone doing something unconventional that works. Thank you.
Pretty clever! Great explanation 👍🏻
Ever considered a career as a teacher? 🤓
Thanks for sharing!
You're welcome Matze.
Some would say I'm always a teacher. Even when I was an engineer I felt it was part of my job to guide junior engineers.
Would you consider sharing this video with your friends on social media?
@@Clarks-Adventure Yes I will 👍🏻 I dont know a lot of people with a boat lifestyle such as you, but there might be other possibilities to use this knowledge. I got a friend with a pretty remote fishing lodge. I think for him this could be quite useful 🙏🏻
Thanks Matze. I appreciate it. I agree that this is a worthy idea for any off grid designer. I'd like to get it out there.
I'm talking with a guy who has a great idea for a hybrid specific BMS. Probably do another video on that soon.
@@Clarks-Adventure Great, looking forward to it! Specific BMS would make it a lot more accessible for people without engineering background. 👍🏻
Lifepo4 is like sunshine in a bottle for your lead. It has the ability to be quickly charge and slowly replenish the lead. Great way to engineer out the problem of leads slow absorption at the top end by using lithiums ability to quickly take up any sunshine power that is available and then give it up when needed.
Yes Luke,. The two together have a sort of magic.
Have you seen my charge controller?
www.emilyandclarksadventure.com/bbms
Hey Clark, This is the first time I've heard of doing this. I like the concept and wonder if you could explain your "dockside" charging system using shore power and a 120v charger and engine alternator charging or do you charge with solar exclusively?
We are really a solar boat.
We have a big alternator but it only runs when we motor and we try not to do that much. We have a 50a ac charger but we never plug into shore side.
We are a solar (and sometimes wind) powered boat.
Jeff, Would you consider sharing this video with your friends on social media?
@@Clarks-Adventurewill do I'm on FB & LinkedIn.
Thanks.
Sorry for the other message. I misread your comment.
@@Clarks-Adventure www.linkedin.com/in/jefferdmannyachtingcapital/detail/recent-activity/shares/
So glad I stumbled onto this post. Now, I wish to become a pat. I'm limited on SS now and living full time in my 34 ft RV motorhome, wishing for a nice big boat around a 40 ftr.. Doubtful that will be a reality. So I have been thinking about this same project. I currently have 400watts of solar and will be adding in another 400 watts in a week or so. Hopefully another 400 before the summer is too far along. I'd even like to add in a little wind in the future, maybe .6kw to 1.2kw of that. It wouldn't be real practical project where I'm at right now as there are a lot of Pine trees and hills around most of me, but there is some wind from the south on occasion without obstruction mostly. But solar is pretty constant during the day from early morning to around 2 except on cloudy days. I'm getting ready to dump a little over a Grand into my system tonight for stuff that will arrive in the next week and then work on more over the summer without the LiFePo4's but those will be coming ASAP along with the BMS systems, I want to have backups in case issues arise, because those aren't that high priced. With combined charge controllers and accessories, this should be doable. If something gives way, I should still have some power even at reduced level to stay in operation. Most of this stuff will be going in the compartment where the Onan was installed, which is coming out soon. I plan on getting one of those little 2kw inverter genny's just in case I need a quick boost to run the 800 watt shore converter if and when needed. A gallon of gas a day or so once in a while isn't all that out of reach.
Hi Brett,
That video is a bit old.
This is how I'm doing it now.
www.emilyandclarksadventure.com/bbms
I have some of the black box units with full function I'll sell for $100 off it that helps. And I have a cheaper contactor. Write me at emilyandclarksadventure@gmail.com directly if you are interested.
Make sure you read Conrad's article at the bottom of this page. No charger available now charges lithium right.
Better to buy mine (that does charge li right) and pick up used chargers and solar controllers that people are selling because they are replacing them with "Li" units.
Great video, I will add to my AGM (8 piece) the li-ion (lev40) in the setup of 24v. Super video thank you a lot
Consider doing it this way
www.emilyandclarksadventure.com/bbms
You're the evil genius without the evil.
Wish I knew how to spell "insert evil laugh here"
Solla, Would you consider sharing this video with your friends on social media?
@@Clarks-Adventureabsolutely
That's my experimental battery setup for my little macgregor! Works great in my mind, so happy to see it's as wise as I thought! I stacked 18650 to make an independant low draw system li ion. I wanted an electric trolling motor as a backup, and knew my system wasn't up to high draw, and got lead acid to be charged by the li ion.
Li-ion and Lifepo4 are different animals with very different requirements. I've put no thought into doing this with Li-ion.
But, very glad it is working for you.
I moved up from a MAC 26x to an Irwin 43. Learned and loved my 26X.
Thank you!.... Getting to start the project using your BBMS
Great
Are you in the EU? We have some units already imported and ready.
If not www.emilyandclarksadventure.com/bbms
A really excellent explanation and battery strategy. I am experienced and quite comfortable with this.
Wow, youtube algorithm is something; i have been combining both types for 2 months now; now let me watch your video here,and read the comments..
Give this a look as well. It's how I'm doing it now.
www.emilyandclarksadventure.com/bbms
All makes perfect sense. Great video thanks Clark, hope this video does well for you.
You're welcome David
Would you consider sharing this video with your friends on social media?
Great information thanks, please don't sell yourself short with the hard sales pitch. You know what, people are likely to support without it. Thanks as always for great content, stay safe.
Except they don't. Our ratio of subscribers to patreon supporters is WAY lower then other sailing channels.
This is freaking GENIUS!
Thanks.
That was years ago. Check out how I'm doing it now.
www.emilyandclarksadventure.com/bbms
Thanks, I have been contemplating the same quesiton and I am glad to hear of your success
I have a cal 40 electric with 48 volt 10 kw electric motor . Dc dc charger and 570 watts of solar. I was thinking the same thing but have ordered a battery bank switch. After watching this video I think it may be dangerous to charge on bank one and then switch to both as the could be different SOC . So after watching this I think I’ll just hook them together and it would be like your system . I have 8 t105 Trojan batteries and my lithium is a 48 volt 50 amp hour. I have an electric truck with LTO 72 volts that is run by 600 watts of solar and I never plug it in to shore power. I do think LTO is better option for this however.
You might want to look into my hybrid lithium lead charge controller. It reconnects your banks for you when it sees them at the same voltage. Just what you need.
I just got prototypes in. Look at this coming weekends "log" video.
This is a fantastic tip. Thank you Clark 😊👍
You're very welcome Jeffrey.
Would you consider sharing this video with your friends on social media?
Excellent video, there is really not much good information out there on this. Appreciate the great explanation.
Have a camper, starter battery and auxiliary: added a lithium, skipped the dc to dc and it’s good, like you said. Thanks.
You should really consider one of these.
www.emilyandclarksadventure.com/bbms
i just love ya'lls ideas and videos . and i will be using them has soon as my wife and I get our boat so you might be hearing from us one day . hope to see ya'll out there in the near future. stay safe and healthy
Thanks Joseph, looking forward to talking with you. Please consider sharing this video with your friends on social media.
Came to this conclusion without testing yet but also concluded protection between between batteries would be required for example 150amp fuses depending on maximum draw . I can also see many arguments from many people however ideal and practice versus cost are different
www.emilyandclarksadventure.com/bbms
This makes everything automated and is the only regulator that doesn't cause low current overcharge.
👉🚐 this one caught my attention right off the bat. Your way of expelling is perfect for understanding how the system works! 👍 On to the next Video.
I love your Chanel,you cover so may subjects in a way nobody else does! Thank you.
I think I need to binge watch all your content and take notes, and I'm sure I'll have lots of questions.
Thank you very much. That was very nice to hear.
Enjoy!
Great video - A very interesting concept. I'm saving this for off grid housing in the future. Thanks for sharing!
Did you ever see Emily's tiny house videos on this channel?
Also, Would you consider sharing this video with your friends on social media?
Found this video after watching your $380 BankManager device video. Good content!
Thanks
I fully agree with all of this because i also have this kind of combination on 4x12v lead acid for 48v system with Lifepo4
I'm developing a hybrid lithium lead charge controller that might interest you. It's a fairly simple board that lets the li and pb both charge as they should in our insulations.
Wow. I found this video by searching for this topic, because i have had exactly the same idea. Thinking about discharge curves, i had the same ideas: lead will deliver the high power when needed while lifepo would keep the lead voltage up in the longterm. The only difference is that i didn't tought about connectig them via a resistor, but first chargng them separately, instead i was considering adding fuses between them. I'll check the comment section also.
Yes, this works great but I'm doing it this way now.
www.emilyandclarksadventure.com/bbms
Seems to solve all the issues automatically and along the way I found that Liis being charged wrong by other charge controllers. This fixes that issue without having to change any of your current charge controllers
Fantastic video thank you. I am struggling with a cheaper brand DC DC charger that gets so hot as soon as I plug in my lead engine battery. I mean hot! So I've bought a victron today to hopefully lower significantly the temp. Fingers crossed victron has addressed this common problem as people are fitting fans to their DC DC array!
I'd return the Victron and use my BankManager.
It doesn't get hot because it doesn't waste energy. But most importantly it charges your lithium batteries correctly for a long life!
www.emilyandclarksadventure.com/bbms
Thanks for the video. This made a lot of sense to me. I will have a good look at your other videos. Have a nice day.
just done exactly what you said a week ago working good and yes the gell battery must be fully charged first
It's even better with a bbms
This was the BEST & info filled VIDEO I've seen in quiet some time....really good...cheers
Thanks Peter.
Would you consider sharing this video with your friends on social media? I'd like the new viewers and I'd like to get this idea out there.
Thanks for taking the time to explain this. Great job!
You're welcome Matt. If you think your friends might also like this how about sharing the video on social media? We'd really appreciate the new viewers.
Thanks. Great video & very smart use of both types of batteries :)
You're welcome Len
Would you consider sharing this video with your friends on social media?
Thank you for sharing all this information. Your videos are very educational!
Thanks Esteban. Please share with your friends on social media.
@@Clarks-Adventure
I will share the video with my friends 👍
Thanks
I don't know what I just learned about batteries... I feel like I learned a lot! If you ever see a 23 foot sailboat with huge letters on the side that say Floaty Boat, raft up with me because I owe you dinner! ⛵ 🔥
Lots pf useful information. Thanks
Thanks,
This is how I'm doing it now. www.emilyandclarksadventure.com/bbms
Right now I have my home network (cable modem, WiFi mesh routers, network switches) running directly off of batteries. I have 2x 100 watt solar panels, 1x 20 watt solar panel, and recently added a windmill. I also keep a battery maintainer, a 2 amp, plugged in at all times.
Whenever the grid goes down, I still have WiFi. It’ll last about a week on just solar. I’m using two leaf acid batteries.
I want to get the proper wires for my windmill. I used 16awg, but I guess I need 10awg or even 8awg.
Ultimately, supporting myself completely off grid is the goal, but it’s so nice to have the grid to keep it topped of for the maybe 7-14 days of the year where their is neither sun or wind.
All I need now is to get Starlink, by Tesla, Elon Musks internet service, and I should never lose access to the internet, or pay a monthly fee for the energy to power it.
Clark thank you so much for this. I have been contemplating just how to integrate some lithium into my system... you have thought 'outside the box' on this one and given some awesome info here. Million thanks.
I'm just finishing up development on a circuit that will charge both types of batteries exactly as they would like to be charged.
Should be available soon
The marriage between lead. And lithium idea is brilliant ! Wow 😲 I’m a electrician and electronic tech , and never thought about that , but ya ! Makes perfect sense, but yes be very careful connecting batteries together, in parallel, the voltages must match or 😵 trouble. Great explanation! ( subbed) 👍
me electric man also and just assumed this wont work but we assume stuff dont we , great to find someone that tried it an works
You covered pretty much everything there and it all makes loads of sense. The only thing I want to point out is that this setup may make the lithium batteries fail. It is not a mid-voltage issue, your voltages all make sense. The thing is that voltage may be too in the middle. Most lithium battery BMS systems will balance their cells at like 14.6 volts or like around 12 volts....So they top or bottom balance. If you spend too much time in the middle...which is best for the battery longevity in terms of voltage....it may mean the cells never balance. Now this would be different from battery manufacturer to manufacturer...and BMS to BMS...You said that you push the voltage up to 14.0 volts....if you actually are using Battleborn as your diagrams suggest. They will die. Why because Battleborn cells balance at a minimum of 14.2 volts for quite a while. 14.0 volts is too little for a top charge. Now likely you do put in higher voltages than 14.0v while charging, so your cells likely do balance a little while that is going on...the thing is passive balancers take days to do their job sometimes as the current is soooooo verrrrrry looooooow. Likely your cells are very slowly getting out of balance....it could be worse...but it will likely get out of hand at some point.
That's good information. I'll crank them up to 14.2 now and again. Kinda want to do that for the lead anyway. Though staying below 14.1 I probably could go a long time before any imbalance became problematic.
Whatever kind of follow up video I do will include your idea. Thanks Allyn.
I'm working with another boater just now on a specialized BMS for mixing lead with lifepo4. Stay tuned for another video. Best feature is it will let the lead charge first then charge the li.
Still working out details.
What I'm also concerned with is holding the LI up to 14 too long. What do you think about that?
It's not an issue with my video proposal exactly, more how my personal charge controllers function.
@@Clarks-Adventure Well...most lead acid charges at 14.4ish volts....so running voltages there abouts isn't actually an issue if you don't cook the lead acid or the lithium...I thought top voltage and the "eqalization" voltage according to Victron is 14.4 volts for the Battleborn. You are kinda in between a rock and a hard place.
Every once in a while you should take your Li up to pretty close to a full charge so the BMS or in some cases the cells themselves don't "go crazy" too....You could manually reconnect to the lead-acid at just the right time in the charge discharge cycle so those two won't pull too much energy. Maybe a circuit that sees a balance occurring and a contactor...Unfortunately holding the Li above 14. for some extended period is the best option. If you don't do it a lot, it shouldn't take too much of a life cycle off in the long run, and sure beats having a necessary cell failing internally.
These are really good suggestions! and this is such an important topic to be discussing at the moment, I really enjoyed the video!
Thanks Reece. Please consider sharing this video with your friends on social media.
This info is priceless. This has been so helpful in my decision making regardig similar issues with my pocket cruising boat 🤗
You're welcome.
You should consider one of these. www.emilyandclarksadventure.com/bbms
Since this video I've realized that no charge controller is charging lithium "correctly" and just connecting the batteries can leave lead not fully charged.
This device takes care of your individual battery banks.
Hey! Nice thinking! I've been thinking along the same lines but got a bit stuck in the float voltage difference problem. I was thinking about having two-way diodes and what not to get a stable voltage drop between the banks to compensate but it felt so complicated. Your idea to just let it float charge the lead bank is clever - it should be just fine.
One thing scared me a bit, which I should tell you about. If you connect them as you say, and then, for some unforeseen reason the BMS turns the lithium batteries off. Let's say you bridge the starter and house battery banks or something and you charge it to 14.7V. After the BMS is off the lead acid batteries will start to discharge... at some point, all of a sudden, the BMS turns on again. Then you have an issue. A lot of power will run over those wires as you point out in the video with unbalanced voltages. So I'd suggest you just put a fuse between the banks. Connect every consumer and supplier to the lead side and fuse off the BMS and lithium with like 150A or similar, depending on the use. It might save you from a fire.
You might already have a fuse, then this comment hopefully help some other boater who just connects them together. Feel free to send me a message the day that fuse is blown and you don't know why.
This is in actually a general problem with all lithium batteries which has individual BMS'es. When they switch on there is potentially a huge current rushing between the batteries. I usually recommend a supplier with a system wide BMS shutdown instead of per-battery partly for this reason.
I just developed a device that solves all this.
It breaks the contact to the li when fully charged and let's the lead finish it's charge cycle. It only reconnects when the voltage of both systems are close. Solves about everything that I can think of.
Video to come. Subscribe.
@@Clarks-Adventure Great! I'm already subscribed ofc.
Interesting video, I'm seeing lots of folks mixing battery chemistries, though instead of getting the battery that's suited to the load like you are, most of them are simply keeping a load on the alternator if the BMS drops the Li battery out of the loop.
I'm in the process of replacing the battery bank in my trawler. We had flooded cells for house and starter bank, and I wanted to get rid of them. I was sick of checking levels, corrosion and such. The wood under the batteries had deteriorated from the acid and the batteries were aging out anyway. Time to upgrade.
I've been using LiFePO4 in my RV for about 5 years and have worked with both drop-ins and custom prismatic packs. After looking around, DIY Lithium batteries are easy to build, cells and BMS are readily available and can be built for about the price of AGM batteries, if you've got the space to work and the few tools needed to do it. If you DIY, they're about a third the cost of good drop-ins like Battle Born.
Our old house bank ran our anchor puller ( ~150A ) and bow thruster (~350A), plus they were available to be combined with the starting bank to start the main if needed. I could have moved the big loads to the starter bank, but I didn't want to lose the ability of the house bank to start the main if called upon, so I wanted a bank capable of big current.
I chose AGM batteries for the replacement starter bank. Simple, powerful, no maintenance. Done.
We use a lot of energy and enlarging the house bank would also be beneficial to our cruising way of life, at this price it seemed like a no brainer.
For the house bank, I bought sixteen 310Ah LiFePO4 cells and made four 310Ah@12v batteries out of them, each with a 200A (400A for 5 sec ) continuous BMS, giving me 800A continuous. Plenty to start the main ( I've been starting it with a 400A class T fuse inline forever ), run the bow thruster, pull the anchor or heat dinner. Each battery fit in an inexpensive plastic gropu 27 battery box with the BMS mounted on top for cooling, though I don't expect that to be needed.
I got rid of about 200lbs of weight and moved the batteries to a better, cooler location for longer life.
My total cost for the batteries is about $2600 for 1240Ah@12v, including the parts for the case. Anyone building them with my method will need a few hand tools, a good voltmeter and a variable power supply, I got what seems like a pretty good one from Amazon for $75.
In the end, if I had replaced my 6V house batteries with AGM's, I probably would have spent close to $1500 and gotten about half the capacity I now have. If I could have found the space to put twelve 6v batteries and had been OK with another 400lbs or so of batteries, I could have matched the energy storage of my four batteries ( in the same footprint as four 6V ), but would have spent about $3k.
I have bluetooth connectivity into each BMS and can see the individudal cell voltages, so if there's an issue I can hopefully find it.
This technology is moving pretty fast and prices have come down a LOT. I kept some lead on board as a starting/backup bank, but we're getting closer and closer to the day when that won't be needed, either.
Admittedly, I don't have a lot of experience with these cells or the BMS, so it's kind of an experiment to see how this works out longer term, but I guess, so is paralleling LiFePO4 and AGM. Ordering direct from China can have some downsides and not everyone has had the best experience. Will my cells hold up for 3k cycles? Will my BMS be reliable? I'll start to know the answer in a few years, but so far I'm impressed with how well the cells have stayed in balance when I capacity tested the batteries ( all tested well and within
Looks like you should do your own video.
What happens if you get hit by lightning? BMSs can fail. But it looks like you have the expertise to just monitor them manually
@@Clarks-Adventure We're coastal, so we're not going to be far offshore, but we have made 10 hour passages. If we completely lost the entire LiFePO4 bank, I'd run down and use the on/off/combine switch to combine the banks and the boat would run off the 180 Ah ( two group 27 AGM ) starting bank.
Our engine is a Lehman with entirely mechanical injection, so that would continue operating after a strike and as a trawler, it would already have been running if we were under way. Assuming the alternator survived, we'd be fine running on the AGMs for an extended period of time. If the alternator died and the generator and chargers had died as well, we could probably run for another 5-6 hours or more with the AGM's powering a limited number of items. We keep a charged phone as a backup nav unit wrapped in aluminum foil, so we can navigate for an extended time ( we have several portable battery packs ) even if the entire boat had no power.
@@Clarks-Adventure Oh, and I don't see much of the point in doing my own video since Will Prowse is where I got my ideas and he makes great videos. My case design might be worth showing a bit, since it's cheap and easy to build and would work well for marine applications.
I hadn't thought about it, but it wouldn't take more than about 30 minutes to rewire all four batteries to bypass the BMS and continue to use the batteries without protections. Normally, the BMS isn't really doing much other than watching over the parameters to make sure nothing is too high or low and doing a tiny bit of cell balancing. In 5 years of using Lithium in my RV's, I've only had one incidence of the BMS disconnecting the batteries, which has never repeated itself. I have had disconnect switches melt because of the charging load with solar, inverter/charger and alternator all charging at once at >160A. The batteries were fine.
Yep
Very interesting video. Well done! I had plans to exchange from AGM to Lithium, but after your video I made up my mind and I will definitely dig into this a bit more and probably ask your advice on Patreon.Thank you!
Wow! I was going full lithium! So I will consider keeping my lead battery that are only 3 years old. That will cut the expense a lot!
Thanks
If you are going to build your own lithium talk to me before you buy a BMS.
There is one being developed especially for hybrid packs.
Marc, Would you consider sharing this video with your friends on social media?
@@Clarks-Adventure done!
@@Clarks-Adventure I will start this project only in October, I keep you posted before I purchase anything. Regards
great video! happy i found your channel. I've been brainstorming how I could add more wattage to my bank with lithium, to supplement instead of replacing my existing lead batteries. Thank you!
You will have to check out my new creation. It's called a bank manager and it controls the charging of the different banks. Should be available soon.
@@Clarks-Adventure cant wait!
Great info...
Down the road a piece, I will definitely need that call.... lol
Glad it helped. Looking forward to chatting with you.
Clark, thank you so very much for this outstanding video instruction and information. I am installing a lithium iron battery into.my.hoise battery banks on SV Medicinal. Your guidance will help me avoid any issues and will allow me to take full advantage of the combined energy output! Hope you and Emily are well! Hope to see you guys in the near future!
You're welcome.
You might be interested in my bank manager to help you charge each type of chemistry correctly.
Can you s ND me the link for the Bankanager information? Thank you!
Doesn't exist yet. I think it will be sold by the same company that manufactures my AC system.
Best thing now is ho to the AC video description and fill out the survey. If you answer yes to the bank manager question you will get an email when we have something.
Strangely now that AC is mostly done I'm finishing the software for the bank manager today. Just re-set up my lab and booted my computer. What timing!
I'm running my 3.2Kw solar system with 24V tall tubular battery pack.
I have 2 lead acid batteries (12V, 185ah each) in series.
Selfmade 24V lithium battery pack of 200ah capacity...
I'm using both packs in parallel...
It's giving too much satisfying results...
I have two comments. Your system has the potential to charge your Li at more than .5C. That's hard on your batteries you might want to add more Li.
And that's an old video. This is a better way to do things. In fact it's the best way to charge LiFePO4 available.
www.emilyandclarksadventure.com/bbms
Wow, this really makes so much sense.
When he talked about linking them together, I thought he would just say make sure your lead has a higher voltage than the lithium, would that not be ok.
I'm doing it this way now.
www.emilyandclarksadventure.com/bbms
Lots of reasons this is better. Mostly it charges the lead and lithium properly. No other regulator seems to.
One big caveat is cold weather. The LiFePO bms will disconnect if trying to charge in below freezing temps. Then the batteries can get out of sync that way.
Brilliant . All I need now is a boat.
And one of these.
www.emilyandclarksadventure.com/bbms
@@Clarks-Adventure thank you for that . To be accurate I bought a Lagoon 40 at a boat show in 2019 through a charter management deal to get me on the property / boat ladder. The boat was delayed due to covid but at least I kept the 2019 price as everything has gone up. I can't install anything until I get the boat back in 2028 , so I'm doing lots of sailing and signing up for courses - mechanical and electrical to try and understand the basics . Your videos are great even though I have no idea what you mean at times ! My girlfriend says you look 15 years younger without a beard by the way 🙂.
Thanks.
My mom says the same thing.
Nice information I will follow up
What a great video. I’m going to use this set up for sure! Great stuff. Appricieate the time youv put in for all us sailers, Cheers.
You might want to watch my later videos.
I have developed a hybrid lithium/lead charge controller.
Will do!
Very timely video, I just ordered a 12v 200 amp hour lithium battery, and was wondering if I could connect them to my lead acid.
Thanks!!
I don't recommend this anymore
This is much better.
www.emilyandclarksadventure.com/bbms
It treats your lithium correctly.
Other regulators that charge to a set voltage all can cause low current overcharging that leads to cell death.
th-cam.com/video/XAOhT2HwKWM/w-d-xo.html
This sort of describes it
Wow! I've been working with Lithium for about 5 years now, building astronomy rigs for mobile DC systems. I never realized you could mix with lead acid, this explanation was terrific and I love your strategy. I've been watching you for some time, thank you for everything! I took up sailing this past year, and have been considering buying an older sailboat and refitting myself, and I was going to go pure lithium - but I love the idea of cheaper lead acid. I think for the pros of lead acid - the extra weight for ballast? Thanks again - I'd love to hear about your AC setup though - with kick and overall amp run - you would need a significant amount of batteries for multi-hour AC no? Some actual numbers of what you burn in amps per day with AC would be super useful thank you.
Thanks Charles.
You aren't alone in wanting to know about my AC. It runs all night in the tropics easily off 2 100amp lifepo4s. It's quite adjustable. As I have it set up it draws about 15 amps at 12 volts and once it gets the cabin cooled it runs about 1/4 of the time through the night. Video is coming but I had to explain how to power it first. Some have already signed up to my Patreon to get help building their own.
I'm currently writing a video to go with this one. The next is why it's good to include some lead in your system even if you are going all lithium.
I've had this idea for a few years. I was just planning on having solar that goes through charger to lithium, and then a charger from lithium to lead acid, with the load connected to the lead acid. Lithium becomes a no sun float charger. For my boat design I am using 3000kg of SLA (40X270ah (74kg)130kwh) as ballast and battery, and was going to use 30kwh of lithium (100% rating) The system is designed to float the lithium around 50% and SLA at 100%. With about 15-20kWh of solar and calculated usage, the lead acids should not get discharged more than 10% for normal usage and an expected life span of 20 years. I hadn't seen anyone do this, but thought it was a good idea. With the combination of solar, wind, and wave energy I would never need to charge from port or generators. Also enough power for an onboard greenhouse which is a must; something I have also seen nothing of on boats.
That's basically what I do with the BankManager. You don't need a dc-dc charger to go from li to lead as the li will float the Pb right in the Pb sweet spot of 13.2v. Your proposal still has the Pb cycling a bit more then mine unless your DC-DC is up to max used amps and of course the DC-DC burns power into heat.
I see you can understand this. I see a lot of my early ideas in your comments. I'm confident you will see that the BankManager approach has a lot of benefits. Especially once you see the problem that exists with current chargers, the low current overcharge issues, and see how the BankManager fixes it.
You are just the kind of person I want to install one as you will be equipped to explain it to others .
@@Clarks-Adventure Your idea may be better than mine. I still have many aspects to figure out. How often the Pb bank would cycle would really depend on size of lithium bank, external input and draw. Initial calculations were with a gyro stabiliser, but may not install. I'm still a few years off building a boat. The design is around 25 metres long and 5 metre beam, but I can't even find berths for a boat that long near where I live (Melbourne) that are secure. Australia has so much coast line, but we have little infrastructure for boats. You may have said already, but how large is your battery bank?
This works for virtually any size. I have a 48v hotel interested.
I have 1400ah of AGM and 200ah of Lifepo4. That's a lot of lead, I had it before the li.
Wow. Timely for me as I am just setting up my charging system on our new-to-us boat. This took some time and thought. Nice job Clark. So you are setting your solar charge controller to the lithium setting as well as your engine charging system and letting lithium batteries manage the lead bank recharging by pretending that the lead bank is just a load like a big light bulb. The lead acts as a buffer for heavy loads and sun-less days so to speak. Is that right? The cyclical deep discharge-charge-discharge-charge cycling is borne by the lithium, which can do that all day. Nice. If the system were to totally discharge totally it would seem that the BMS would lose its mind when charging in parallel with the lead bank and you'd have to disconnect everything and start from scratch. My guess is that this has to be avoided by sizing the lithium bank correctly in the first place. Hmmm. Another question...So do you keep your start battery (lead) discrete, or just let all the batteries play together?
Close, but not exactly.
I really can't keep up with questions individually here. I'll make another video or two on this eventually.
Remember my offer to do one on one help over patreon.com if you want more in-depth or timely help.
Nice Ericson in the background. I'm on a 36C. 'Compliments to the captain!
👍👍👍This is the best instruction and informative video I have ever seen!
Did you watch the follow-up video?
Another is coming about the battery bank manager I've developed.
@@Clarks-Adventure Yes have seen it, also very good! Looking forward to the one about the battery bank monitor.
again very nice explanation , thank you , Blessings
Thank you for the video. It is very interesting. I really think you might be onto something here.
You're very welcome caparn
Would you consider sharing this video with your friends on social media?
Love your channel, I learned so much from you guys. We just started our channel. We are completely new and so grateful for all the info and inspiration the two of you give.
You're very welcome. Hope your channel does well
Would you consider sharing this video with your friends on social media? I'd really like to get this idea out there.
Thanks I am also trying this on my channel but my lead bank is small to help lead inverter
Since I did this video I've found a better way to do this.
www.emilyandclarksadventure.com/bbms
Charges the lead fully and seems to be the only way to not cause "low current overcharge" of the lithium.
Hey cool video! I made the same experience with lead acid batteries. The 13.2 Volt level save the batteries from sulfating the plates. Very cool idea to combine them with Lithium batteries. I would keep the starter batterie separated but charged by the bank with a small step up converter. For emergency I would install a set of supercapacitors. You can load them with a step up converter even from a very low power source and start the engine with a nearly discharged batterie or via the solar panel. Thanks for sharing this video! Have you heared about the guys from a boat called "Chuffed", the solo sailing girl on her boat "Karl" or the adventures of "SV Delos"?
Thought-provoking to say the least. TY.
Thanks David,
This is how we are doing it now.
www.emilyandclarksadventure.com/bbms
@@Clarks-Adventure Very interesting. I have a ton of questions but a year or so from starting the project. E&Cadventure is at the top of the lithium refit list. TY and GL, I hope this top shelf engineering is very rewarding. You deserve it.
Can't believe I've only just subscribed. Super useful channel. I have an AGM LIfePo combo. AGM for the start battery and bow thruster and lithium for everything else. They are not directly connected (although I can do it manually if say the AGM needs a top up), but they are connected to the same DC to DC charger. With 120 AH AGM and 300 AH lithium I'm finding this is plenty for our needs, but we don't of course have air conditioning. A good solar array and wind gen plus a 2000 watt inverter complete the picture. I'm also thinking generators are no longer necessary these days, although it might make sense having a small petrol one stored away for occasional use.
I'm finishing up a device called a bank manager that will let you remove your dc-dc and still recharge both your banks just the way they need to be charged with no loss of energy. Got picked up by a company that will sell them soon.
Glad you are enjoying our videos. Welcome aboard.
Great video Clark, and a great idea too. Also very nice you are willing to help people with their setups. I will be sharing this video with a friend of mine, which also means I will probably end up helping him do it if he decides too. But I enjoy this stuff too. Thanks for sharing.
Thanks Steve. Share away, I appreciate the new viewers.
Excellent presentation, and a very good point you make here. I am working on a 24V lithium only bank, to power just the inverter. I don't like the idea that the BMS can decide that I don' t need my AIS and Chartplotter right now, because one cell is out of ballance :-) This way I can support my 12V system, and know that the BMS can't mess me up! BTW, I already converted to Induction cooking. I modified two 800Watt chafing dish heaters so they will go up to 180 degerees celcius. What a great time to live onboard!
Thanks,
That is another good reason to do my hybrid thing. In a couple of hours I'll be releasing another hybrid video that talks about that kind of issue. Sort of the opposite of the first - why I think you should always carry some lead batteries even if you go mostly lithium.
th-cam.com/video/sqT27KbxRec/w-d-xo.html
Since you went split voltage I assume you will be using a buck/boost (dc-dc charger) converter to charge one if the banks?
@@Clarks-Adventure I will use the 12v inverter to charge the 24v inverter/charger. Bit inefficient but half way in the project, I have to be careful with my spending:-) The plan was to get a well regulated 24v alternator. All the puleys and mounting points are already there. Using your engine as generator makes more sense with lithium too.
Just had an idea. If you used a boost converter set at like 28.4v or whatever to charge your lithiums and added a voltage sensitive switch to turn it off once it hits top voltage and on again when there is charge and voltage goes low or a clock says it's time. You would have a more efficient cross charger with low cost.
@@Clarks-Adventure That would work, but with a bit af a dwindling income I am trying to finish the setup with the parts I already have :-)
Sure I understand. If you ever want you could out one together for like $50us that charged at low amps.
A video showing how you balance the amperage using the resistor would be super helpful in building my confidence before making a big change to my system! Thanks for all you do.
I have since developed a device called a bank manager that will be available for sale soon. It takes care of all that and makes sure that both types of batteries charge properly.
You don't have to install special li charge controllers so it saves a bunch of money.
Go to the air conditioner video and fill in the survey in the description to be kept informed.
@@Clarks-Adventure I guess you mean "charge the batteries properly" NOT "charge the batteries probably" These auto correct spelling innovation is often a step back not forward! André
Yeah mine hates me.
I guess early in the development cycle probably might have been the right word.
you could use a small wire with gloves if it burns in two go next size ore 2 tiny strands
Yep. But a power resister is cheap.
But best is the now completed BankManager.
BOS LE300 seems to offer these advantages with built-in BMS that manages the interconnection of the 2 chemistries.