Active Cell Balancers are Usually Pointless for DIY Solar Batteries
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- เผยแพร่เมื่อ 24 ก.ย. 2024
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Fun videos coming soon! I was super sick this week and am finally able to talk on camera. Once the lab is built up, we will have room for some pretty awesome 48V system tests and more! I can't wait :D
I also have a tesla SLA I need to swap for lithium, so that video is around the corner :D
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If DIY is not for you, but you love solar and need an offgrid system, check out Tesla Solar. Low prices and great warranty, and they can take your entire house offgrid with their new Powerwalls: ts.la/william57509
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Ah. I thought you sounded like you were coming down with something in the last video. Glad you are better.
Any hope for all-in-one systems with a 230V inverter? Best regards, random Finnish guy.
Oh that's what I ran for my Tesla solar charging system. Lv5048 mpp. Great inverter for 240v
Thanks for these videos. I'm learning so much here. Your presentation is perfect: straight to the point, no fluff. Thanks again.
@@WillProwse Thanks! It'd be great to have reviews on such items also. With affiliate links to Amazon UK and DE of course. :)
Active balancers are needed w LifePo4 connected in series. I agree about the cells within the cells, but it'd been super cool if you mentioned voltage differentiation between assembled batteries when connected in series over a duration of time can be bad.
That's what I've found. Each battery has it's own BMS. When hooked in series usually the first battery reaches full capacity and then shuts down charging. The result is the other batteries don't reach full charge. When I installed the battery balancers they all charge to maximum capacity. My balancers have a display showing the voltage of each battery in the series of 4 and you can see them working
Can you share what product you’re using for series battery balancing?
I’m aware of the Victron balancer that (by the size of the heat sink) appears to be an excess charge burner. I could be wrong.
Then there is the Heltec HT-10C that is a din rail mounted active charge shunt with an LCD display showing your two battery voltages and SOC%. Found that on AliExpress.
If there’s anything else out there I’d be grateful if you could share as I’ve yet to make a purchase.
Almost tempted to get a fully isolated 24/12V DC-DC converter, a pair of relays and a current limiter and fiddle around with an Arduino to Jerry-rig my own ‘equalizer’.
FINALLY some common sense on the subject, THANKS Will.
People talking about these things on forums driving me insane.
Yep, lack of proper knowledge is rampant. They only look good in theory, very limited use case.
Great video man. One more thing about cell unbalance is about current leak. It is one of the major responsible for the need of cell balancing. DIY battery with various cells with different internal resistance and capacitance can be well matched in both total capacity and internal resistance for each groups, however if there is some bad apples cells in these groups the entire cell matching will end out to be ruined anyway!. So this is SUPER IMPORTANT to make the BOUNCEBACK TESTING!! It consist of draining all lithium cells to 3.00 or 2.50V depending on the specs and then to wait for few days. Then you re-measure their voltage. If some have significant voltage drop then these ARE BAD APPLE. Just discard these cells to recycling and keep all other cells. what happen during this test is that you bring cells to very low SOC which allow you to see current leak effect at a much more delta V then when these are recharged. In fact what it does is that it bring the cells to their knee point where the voltage slope get nearly vertical so every uAh or nAh loss are easyer to perceive!... remember: capacity test, then internal resistacne test then bounce back testing.. and THEN you know everything you need about each cells you are assembling so that your pack will be a succes... but yes it is more work as well !! I did that back in 2008 on my ebike with 432x 18650 from makita salvaged pack and the bike ran 12000km with bery minimal balancing... it had NO BMS ! Doctorbass
You saved me from myself!
I was gonna buy an active balancer because the Daly 16S 80A BMS is only capable of pushing 30mA while balancing.
When I got the new 25Ah cells, they all read 3.331V to 3.332V. I thought they were all charged to the same level. They were not!
Now I understand why I don't need a balancer once it's all balanced after a two days of letting the BMS do its thing. Thanks.
GREAT Video!!! To many people fall into a "more is better" way of thinking. A lot of times, good enough is all you need and adding more means you are paying extra only to reduce the system reliability. Often times *less* is more.
Here is another point: If you start with matched cells, the only thing balancing does is allow you to squeeze the last little bit out of the battery. If your voltage setting is even a little conservative, the extra storage you get is minimal. The money would be better spent on larger capacity batteries.
Ive seen these active balancer used in a brand new electric bus in china. Its better to have it than not to regardless if the battery is brand new or not. It will extend the life of the battery bank. Batteries are more expensive than this active balancer that will protect it, its a good investment.
A bus has an extremely high amp draw and is charged likely daily....this is a much more severe situation than home use....if you are doing heavy draws than you are correct.....
I am using used pouch cells. Tried matching them the best way I possibly could, but have some issues. In this case, I am using a BMS and an active cell balancer. These are working super good so far. But I do agree with you about having just another thing that could fail. But for the money, its one more thing that I don't have to worry about. 8 7S LIPO packs at 48AH, and so far so good. They are keeping them within 40mv. One BMS, and one balancer per pack.
Man you make a great teacher. The way that you explained amps and watts and watt hours. I have been trying to get that straight in my head forever and after listening to you explain it, I can look at something and figure the math out in my head.
Ive been doing some experiments with smaller LiFePO4 cells, with and without a balance connected, top and bottom balanced, IF you stay within 20-80% charge of those cells they will apear balanced, once you get out of that range it WILL drift and will worsen with each cycle. If one cell drops too low or high the BMS will disconnect the load, now depending on the balancer (mine will do up to 6A and balance voltage to around 0.2mV in my testing) I can balance those cells from becoming too far out of range at the top and bottom of each cycle (its more effective in these regiond). It doesnt matter which technique i use, they will all fall out of balance and worsen with each cycle due to cell to cell differences and the result would eventually end up being one cell being fully charged and the others only half, in my case i need some way to move that energy around to spread the loading off one cell constantly.
I need a system that i do not need to constantly monitor, i dont want to have to constantly check or remember to check every few cycles too see if they are all ok.
Will,
Your knowledge is amazing and to impart it in the way you do is indeed gracious and immensely appreciated.The 400 Watt Solar System Blueprint is a work of patience and beauty and was presented to me on my 72nd birthday today. I will use it on my conversion. Sincere thanks.
You are extremely gifted Mr Prowse, you are highly blessed with the gift of Wisdom, knowledge and understanding.
in DIY solar most people do use and make DIY batteries usually from used 18650 laptop batteries which is what these are ideal for. these do massively increase usable capacity in a larger battery bank when running to full 100% discharge as one or more cells will deplete before the others and voltage start to fall away fast on that cell bringing the whole packs voltage down below cut off, with the active balancer it is able to keep that cells voltage up for longer until the other cells reach full discharge or close to it alowwing you to pull more watts from the pack.
This was fun to watch 4 years after seeing it when Will first published it. Thanks Will for stepping out there and sharing great information and opinions on LiFePO4 batteries and supporting equipment.
Since that time we have endured the old and bloated cells from china being sold as "grade A" cells coming to us in mismatched sets - a good reason to have a balancer to cope with mismatched cells.
We now have a few more options for smart bluetooth enabled bms systems - some which include active balancers - so our battery packs are always in balance.
In the last 4 years LiFePO4 enthusiasts have gained an increased level of knowledge about the characteristics of LiFePO4 cells.
Will might have a different opinion today...
My Use Case: My $100 Daly 200A BMS passively charges my $1000 120AH 52v Lifepo4 equally but NOT during discharge. So my 10A AB that cost only $45 has two roles 1.) Balance the cells during discharge(and during charging doing the extra hand ) 2.) Since not every cell is perfectly created equal especially as they age, you spare the need to closely monitor each cell's health by installing an active balancer as based on battery data sheet there could be 6000 cycles for a given condition and that's more than 8 or more than 10 years of life. This means that after 6mos or 1 year or 3 years or more when the battery capacities change overtime, you have that extra hand to help you manage the differences.
Bottomline, it is pretty cheap to spend for an AB to protect your very expensive battery cells and also avoid downtime to your system in case your BMS config goes beyond the threshold and trigger an auto-shutoff to protect the batteries because of large cell or total voltage difference during discharge for example. You also get peace of mind knowing that something is in place to monitor your battery like you hired an extra personnel aside from the BMS to do an extra job.
Thanks Will👍This quick video answers many questions I've been trying to figure out. Keep rolling them out. Look forward to everyone of these. They are educating so many. 📹
022822/1735h PST 🇺🇸 Thank you for exposing the truth. I have been following your scoops all the time. Years ago, you spoke about, the Good, the Bad and the Ugly sides of “Active” Balancers if it’s required or not or to depend on a good BMS, in stead. I chose the last one. I didn’t go for Daly, though. I was interested in JBD and ever since the induction of that device, I have had no issues, no over charging, no thermal run away or undercharging. Of course I had to configure the JBD system and it worked well even after 3 years plus. I thank you once again. Please keep rolling more technical details on PVC, LiFePo4, BMS, external chargers ( thanks for introducing AIMS 75A) and expose fallacies. Take care and 73s…
One of my reasons for using those active balancers was to get rid of any electronic switch between the battery and its load. Having LiFePo4 cells which have a constant 6C discharge rating and therefore can put out about 780A a BMS is simply not working as there is none for such an amount of current. Utilizing 4 of those cells as a good car battery replacement is just a breeze.
How about a video on the REC-Active BMS?
Very true. I build battery packs with used cells, so I always put these in any battery pack I sell. Even when using used cells they don't balance often unless something's wrong with the battery pack.
Hay Will, when are you going to order a huge amount of 100ah LIFEPO4 battery kits with BMS and ship them to your subscribers for those huge savings?
Oh man I wish. I just payed full price for a new LiFePO4 100ah that I received today. The profits are razor thin for cell manufacturing so idk if we will get them cheaper anytime soon
Well, poor guys like me gotta try! Love what you do bro, keep up the amazing work!!
Umm, addressing your first point, new battery packs eventually become old packs though right? Time and cycling usage may eventually cause cell drift. We all like to remain young & healthy but time waits for no man (or battery) unfortunately.
What we need is a BMS with an "active" type of cell balancer *built-in* in addition to other normal BMS functions like LVC, HVC, LTC and Bluetooth monitoring. Its kind of ridiculous to discharge the high cell's energy out as heat because the BMS body now needs an extra large heat sink which costs money and takes up valuable space.
Moreover, by definition, if a battery pack is out of balance, there is a "high" cell and a "low" cell somewhere in the array. Those two cells would be identified and be connected together with MOSFET via multiplexer and PWM modulated so they even each other out. Saves power too and reduces heat in the battery bay. Expending the high cell's energy out as heat is simplistic old design.
"Active" balancing is a great idea. Depending on the firmware and thresholds used, an active balance should sit idle until such condition arrives that balancing is needed. It needs to be incorporated directly into the next generation of BMS.
No, you simply don't need it. It's fine without
No, passive balancers give off a teeny tiny amount of energy over a year. If your cells are matched, the balancing won't even be triggered. So zero loss will occur.
@@WillProwse Thanks for the reply Will! BTW, this is the best solar battery channel on TH-cam! Love the content and keep it up!
True, those 22 to 24AWG balance wires cannot carry much amps. In an ideal world, we get all the same impedance balanced and manufacturer inspected cells to start with. But most of us buy Chinese made & distributed Ali cells from sellers with questionable economic morals. ;-)
Active balancing would open the door to use thicker balance 14AWG cable. It strikes me as odd that a little quadcopter's tiny 12Wh Lithium battery has the same 24AWG gauge balance leads as my upcoming 14,400Wh Lithium home battery (3 orders of magnitude) because that's what the *all* the BMS's and RC chargers come with. As the cells get larger by orders of magnitude, should not the balance leads become larger also and scale along?
Yes, in a more idealized world we wouldn't need balancing at all because of tight manufacturing tolerances and high integrity distribution change made of people of the highest moral standing. In an idealized world, we wouldn't inadvertently over-discharge or over-charge the batteries ever and slightly damage a cell over a period of 5+ years of winter/summer use. In an idealized world, our solar battery arrays would be built and inspected by professional power technicians for free or maybe the price of a Subway sandwich.
Well what I was trying to get at is such a next-gen BMS with active balancing can take advantage of thicker 14AWG balance leads whereas now they can't really due to small 24AWG balance lead cabling. There is possibly a chicken-and-egg scenario here.
I was one of the folks under the misconception that i needed an active balancer. This was because it is the drift over 15 years i was concerned about, not 6 months. Once built, i have no intentions of continually checking the battery balance....it simply needs to work flawlessly from day one, for the next 15 years.
Thanks for the input
Pretty much me here, I'm using used cells in adverse environmental conditions, give me that toy that make it fnf please.
Thanks, Will!
Even if some seem to hate it I really like my QNBBM. Have only used it twice though (once per year)...
When I built my battery for my boat, 2P4S 320Ah@12V. I was searching for a BMS that could also handle that startmotor of 2000 W. The only ones I found that could be ordered in Europe at the time were open circuit boards with no coating etc. Not the kind of BMS I wanted to install on a boat with high humidity and salinity.
Instead, I just used well-matched, top balanced cells with over-voltage and under-voltage protection and a cell logger for warning of imbalance between the cells. But I also wanted an easy way to balance the cells if I had an issue even if I did an ocean crossing at the same time.
For me, the QNBBM is a good option. I have everything wired and ready. If I find any issue of imbalance I can then just connect the QNBBM and have things balanced pretty quickly. So far I have never had any issue with any imbalance and over a years time the current imbalance between the cells are 0.001V.
New technology always has early adopters. It would appear scientifically the precision and repeatability of measuring voltages or the delta between cells would have the most cumulative affect in long lived storage chemistries.
Thank you for this video.
I picked up a small 7s and 8s equalizer for testing since I plan to use recycled cells. The equalizer will only transfer power to adjacent cell groups. So you can still have an unbalanced pack if using one of these equalizers (Cell groups 1 and 8 off by 0.3v but adjacent groups are off by less than 0.1v which is the threshold to start the active balance to adjacent cell group). Mainly using these in old UPS that may not actually get up to the required voltage for balancing with a cheap BMS. Programmable BMS is overkill for a cheap UPS.
Will I recently watched your review on the new 12V 100ah SOK w/bluetooth and built-in heaters. I purchased 1, but now want another to make a 24V system. You mentioned not series connecting these batteries w/built-in heaters. Is there a work around to keep the life of my batteries for this type of series connection?
Can you do a video on sterling alternator s there more efficient than solar as can charge battery bank quickly while driving
Alternators aren't designed for lithium. The charge rate of lithium is too high for alternators and it will overheat and burn out. At 3000 rpm with extra fans and ventilation it make work but at your own risk.
@@neliosamch3195 sterling alternator they have cracked the code on best way to do it ,
@@vrtactical768 I haven't seen it yet but I know Honda, Yamaha and other generator use a double system conversion to convert it to pure sine ac waves then back to dc.
I know this video is 3y old, but are still convinced about that?
I have built a 16s 280Ah LiFePo4 battery with EVE LK280K cells and I top balanced them before using them; after 4 months of use with a Seplos BMS I now have 120mV deviation at 55V; when new, deviation at 55V was 20mV
Thanks Will for the heads up! Extremely helpful when you take the time to explain when and why it is a waste of time money to overcomplicate life. Teach us the Beauty of Simplicity Will!
If you use 4each 12.8 volt economy Lifepo4 batteries in series to make a 51.2V battery, do you need a balancer to match each battery assembly in series. It seems there could be a danger in over/under charging the batteries in series.
Hi Will!
Just a note about the 180 amp/hr Calb Lifpo4m battery I have on my boat. Has 490 watts solar thru a Victron 100/30 solar charger and also a Promariner ProNautic (rebranded Sterling) 12-40 shore charger. Batteries upon arrival all read same voltage. Put pack together as you recommend and attached a Daly 200 amp BMS. I also included an active balancing system just In case.
My observations of charge and discharge behavior over the last 9 months are:
1) Initial charge - all cells initiated charge (solar or shore) equally. Rising within approximately .02 volts of each other until reaching about 3.30 volts. Then the #1 cell starts to pull away from the others. Cell #2 soon follows. Cell #1 continues to rise fastest untill reaching 3.65 volts at which time I terminated charging. At this point cells #3 and 4 are still in the 3.3 volt range with active balancers trying mightily to catch up. After stopping charging, cells slowly regain balance as pack sags to 13.4 volts (approx). This same behavior was repeated daily for the next 4 weeks (Hoping to see a change within the pack)
Reconfigured the pack do that cells #3 and 4 were now #1 and 2. Was better for 2 or 3 days but the the pack reverted to the same behavior.
My solution has been to set bulk limit to 13.9 volts which stops the charging (solar and shore with #1 cell around 3.51 volts). Cell # 2 reaches about 3.45 volts and cells # 3 and 4 lag behind around 3.36 to 3.34 volts respectfully. Under all circumstances discharge follows the same profile. Cells begin to balance (active) as pack begins to sag, as a whole, to around 13.4 fairly quickly (couple hours) (at this point all four cells are within .02 volts of one another) and then more slowly till stabilizing at 13.2 volts till recharging starts with solar the next morning.
Your thoughts?
What was capacity test results before and after using active balancer?
Also, due to the voltage curve, having a single cell shoot up is very normal and only happens at the SOC extremes. You could top or bottom balance, but each cell has natural capacity variance, and that will happen regardless. But yeah, what were your capacity readings? That will tell us everything
@@WillProwse Hi Will,
Thanks for the instant response. Never checked capacity like you do. Was new to Lithium technology and was leary of pushing the boundaries. Have never been able to get the pack to over 14.0 volts because of the spiking cell. How accurate do you think a capacity test, under this senerio, would be?
@@marktinkler6897 That is one of the reasons I don't like lipo batteries, even new ones do the same. Active balancer won't help much. In my opinion Nissan leaf batteries are more stable. But I prefer the panasonic ncr18650b 18650 3400mah 3.7v batteries or Tesla's.
Are the Equalizers necessary for 4 12v batteries hooked in series on a solar bank system? using 12v Valence Batteries, not sure all are same amp hr.
If someone is doing what you preach, probably not necessary. However, for those people building massive packs of used 18650s, like a 14s700p, I would want the added security of using repacker , plus good BMS, plus active balances, plus a cargo container to hold the batteries separately from my house
hey...i just baught some lishen lto 16ah cells and after just 5 partial charges they are way out of balance..i use no balancer and was thinking i wont need to look for 3 months...i just got a clue here when you said bottom balance..i dident do that..do you think that is the problem?my aplication is fast as posible charge for an electric bike.
I am using a 100 amp lifepo4 dally bms, the overvoltage cutoff is at 3.7v per cell, is it ok for the battery or i need to purchase the manual parameter setting bms(Smart Bms)
I bought used 1 year 6 SOK 12v 100a n had one in the middle completely drain n shut off, I got it back working again but I made sure they were the same before going 36v, might be faulty?
could you please make a video about the benefits of not charging lifepo4 above 80% state of charge and not discharging below 20% , and how to relate charging voltages to a specific state of charge
So, with 4 New SOK 12v 280ah batteries wired series parallel for 24v, I do not need a balancer
with a diy battery bank is it necessary to run a bms or can I just run as is . this would be a small solar array with a vectron 100/20
Here is a scenario I don't see many people thinking about. You have a set of batteries that are all the same capacitance but with time their internal resistance changes. Now those cells that have higher internal resistance will have a higher end voltage when charging and possibly have some of that bled off by the BMS. So over time these batteries that all held exactly the same amount get thrown out of balance by the BMS which bleeds the weeker,higher internal resistance cells . I'm not a big fan of bottom balancing, draining everyone down to the same point but I can see where it has some Merit. As you say most of the time batteries stay in sync very well.
love your honesty Will !!! this will make you successful youtuber !! your honesty will make you stand out and better than the rest. I can already seen this ... and I totally agree with you on the active balancers ... I think the people don't know the difference in voltage that needs to happen between cells before the balancing is triggered
This doesn't give me a fuzzy feeling doing initial charge on Ducon 302 ah cells in series 1 cell jumps to 3.48 and above the rest are 3.35/6 added the jk bms to bring them up together and it won't let me pair after reset of password
hi, i just bought 4 tesla batteries to do a 48v. which bms you recommend? i was thinking about a daly bms but dont know with how many amps. any suggestion?
what about huge diy powerwalls? say i have a 7s1000p powerwall. how can i balance this battery system but separately control the capability of this 2600ah powerwall.
Interesting, so balancers not needed on new batteries.
Speaking of batteries, what do you think of the RELiON winter ready LiFePO battery séries that can be charged down to -20c/-4f ? They are like $300 more then their regular battery
They seem awesome, but so expensive. I'd rather buy a $20 heat pad and make my own. Septic tank winter heaters hook to 12v source and turn on at near freezing, so not programming necessary and takes minutes to add to your system
DIY Solar Power with Will Prowse well, that sounds like a much better method. Especially since you can’t put those RELiON LT in series. Trying to figure out the best cold weather solutions for up north. Thanks Will.
They sill work great after a year and keep my Winston pack always topped balanced.
Great explanation Will! Tell it like it should be told. I learn something most every vid from you I watch. Thank you!
I have Cmax lithium battery what bms do you recommend is for car audio 30k watt
My home is 4 stories tall I park my RV behind facing North,so I get no sun all winter long ,I respect all you do but I can't use what you show ,thanks still learning.
I use active along side normal daly bms. I use solar controller to charge 4s to 15.8v, so the daly would never balance, by time it did, something would be miles off. The next step is an over voltage and the bms kills power altogether to the controller etc...... 😒 So active is there to keep things in check. It's never ever lit up... Which I expect to be the case on new cells but in 5/8 years of never balancing who knows. I'd rather find out at 0.1v variation then 4.2v 4.2v 4.2v 3.2v
I am researching balancing cells because my 12v 200aph battery was discharged and now the mppt is bouncing the voltage.
I love the qnbbm balancers. I have some pretty cheap batteries and I am a bit lazy to match them up better. For this purpose they are pretty awesome.
hi mate, do i really need balancer for 6 cells 40AH LTO battery?
great content.. I was one of those people.. I will not make that same mistake on my new system...Thanks
are low temp cut offs pointless if batteries are kept indoors in a heated and cooled environment?
What about your video
"DIY Lithium Battery "Active Cell Balancer" Explained and Tested. Great for LiFePO4!"
You show a active cell balancer that is a little board, do you still need to use that?
Deligreen 8S are still working great after 2 years.
Where do I Start.... I'm getting a beating with 2 SOK 206ah 12v connected in Series, Powering a 3K Growatt and 1460w in Solar Panels, They won't Balance and shut down constantly!!!!
The big use of these active balancers are in commercial applications where each cell group is monitored and the data is transmitted to the company responsible for maintaining them.
For example, if your city buys some electric street sweepers, with a 4 parallel cells per group, if one cell gets a fault and disconnects, the whole battery is only at 75% capacity without active balancing. If used in this condition for long, the other 3 cells will go to cell shutoff voltage each discharge cycle, accelerating degradation on those cells.
With the active balancer, the street sweeper will keep working with 99% capacity until the company can get out to it and replace the bad cell or module.
The active balancer only needs to have a fraction current capacity of what is pulled from the battery when there are a lot of cells in parallel and the load is intermittent.
As active cell balancing gets cheaper I think it can be incorporated in any BMS and it will allow a weak cell group to stay healthy longer. Think of all those laptop batteries that have one bad cell group because it got weak and then was sent to high and low voltage extremes till it degraded to a useless value. An active balancer would have kept many of these alive for another year or so.
@@JM-yx1lm , I’ll post the link to the video about the battery company and street sweeper. If it doesn’t get caught in spam guard it will show up.
@@JM-yx1lm, the spam guard is set on DEFCON 4 on Wills channel. But there are a few virtue signaling municipalities who bought some and run them, probably after the regular truck does all the work. Lol
I already have my first thermal runaway with a 24v pack, all new cells. One of the cells internally shorted and self discharged, the other batteries in the pack begin to dump the charge (it was like 80%) to that one cell. The only thing that saved me was the bms, a fuse and some 3m intumescent foam i have between the cells.
Until you see a thermal runaway, recommending less safety features seems fine. But is not.
What chemistry?
@@WillProwse NMC
@@jotatsu ohhh ok makes sense
I use those Deligreen, they work great.
Thanks - that was good info. However, I haven't had problems with that side of the equation. I've just finished building a solar/battery/inverter for my car. Really the biggest learning is getting the current to flow unimpeded and connectors, terminations and cable are usually the culprits producing voltage drop and heat. Just going by current ratings alone are not enough. I see connectors rated at 10A drop 2V at less than their maximum current, similar problems with cable. I think that this subject would be a good one to tackle Will. Perhaps even some demonstrations?
Maybe you can answer this question for me.. what if i have 4x 12v-200ah batteries each with their own BMS and made of 8x 3.2v-100ah cells. I want to connect them for a total of a 28v-400ah system. Since you said not to connect more than 2 battery packs in parallel, can I use an active cell balancer connected after the BMS and equalize all the batteries together to prevent charge imbalance issues? Hope you understand what I'm asking. Or could I somehow have a 5th BMS connected to the other BMS on each battery pack? Or am I going about this wrong, and need to get like a 32 port BMS?
My Jackery 500w has a regulated 12v port I know. If someone has another brand that is not regulated, can that fix that with the Goal Zero Yeti Lithium 12v regulated cable? Thanks - great work.
Excellent info. My education continues.
When I connect batteries to get more power or voltage and they have internal BMS, do I still have to use an external BMS?
Please can you let us know if the daly and bluetooth bms have a minimum current needed before they will allow charging to commence? Some bms i have seen and used in the past required a few amps minimum before it would turn on and charge the battery.
What are the voltages, you recommend, for low voltage disconnect and absorption / high voltage, e.g. applying an 80% usage?
Do you simply use the BMS default settings and trust them? ;-)
For LiFePO4, the BMS setting are good, but I do set upper limit voltage to 14.1V. in my tests I get 95% capacity and none of the cells shoot up much. The low voltage disconnect for LiFePO4 BMS is actually pretty conservative, usually 2.65V. I like that cut off
@@WillProwse I am soooo glad that you are in the 15-95% club ... personally I shoot for 11% but we both agree on the 95% ... These ppl that are doing the 40-80% to make their batteries last 5000 cycles instead of 4000 just drive me crazy sometimes. I figure by the time our batteries start even getting close to these numbers a newer/better electrical storage capability will be out. My opinion is if you have a battery that can do 200aH -- then let it do it ...
@@WillProwse Ok, thanks. That's very interesting, as the manufacturer of my cells (winston prismatic LiFeYPo4 200Ah) is showing no voltage below 2.8 volts for discharge and not higher than 4 volts for charging ... maybe a difference caused by the chemistry? LiFeYPo4 vs LiFePo4?
@@dirkwelzel5384 if you want 80%
chemical compositionLiFePO4
Nominal Capacity8Ah
Charging voltage3.65V
Nominal Voltage3.2
Cut-off Discharge Voltage2.0V
3.65×80÷100=2.92 x # of batteries in series.
When combining old with new batteries to be safe I use high 90% low 40%
Believe me "You don't need an active balancer"!!! Yep, until you do.
Good post, please does 10 deep cycle batteries in series need balancer
I built my batteries from used laptops running baitrium, built my brothers batteries from used laptops with batriums both systems 4s 20p like hp powerwall 14 batteries total his bank an mine. ran mine for 3 months no baitrium just voltage displays no problems then I got the baitrium would not run another diy battery WITHOUT it. Shows so much info
I repair and diagnostic Audi/VW EV batteries, I agree with you on active cell balancing for Home/RV/Sailboat setups not being a prerequisite.
Do you say there are no active balancers in EV battery
@@suresh-visprasolar145 . EV all have cell balancing
@@suresh-visprasolar145No, all VAG group EV’s do
I have used cells, and don't need active balancing, all I need is a bms, it stays balanced without either!
HI Will, tilll today i still keep wondering how does the BMS handle the high current application such as using the Lifepo4 in auto start application which will burst 500-700 amp in a few seconds? Some more i can see that most of the BMS are rated at 200-300amps. Above that the price does not make sense anymore.
Hi Will - can you review the Ultramax batteries that are widely available and sold in the UK please? Or do you have any thoughts on them?
The problem with what you're saying is that these BMS only starts balancing at 4.2v per cell NOT from 0%-80% SOC that's why it doesn't need that much amps. Mine is set to charge only up to 3.45v or 55.2v (total) and these expensive BMS advertised passive balancer won't balance them until it reaches a certain voltage. Brand new or used, you'll need an inductive 8A-12A active balancer. It'll start balancing your batteries from 0-80% SOC.
Do we really need an active balancers, they say in EV there are no active balancers
@@suresh-visprasolar145 Well, I'd say EV manufacturers dgaf about the lifespan of your batteries. They want your batteries dead after the given 8-year warranty or mileage. They don't want your batteries to last too long; otherwise, they won't make a profit off of it.
Though I believe BYD uses Lifepo4 batteries for their EVs and uses active balancers.
Great to know as I have some up and coming videos using these types of cells, but the cells I will be using are Brand New!! New Company out of China, They want me to try out the large supply of cells for different applications. I personally use the active balancer on used Lithium-Ion cells and with a BMS(Typically a cheaper Chinese one). Happy to know I won't need them on the other types mentioned in this video, just a good quality BMS. Another Great Video Will!!!
I have a question, I have a bumper pull trailer I want to change out my dual 6v=12v system that's located on the tongue of my trailer exposed to weather (they're in individual battery boxes) and I want to change over to one or possibly two 12v lithium ion battery(s). Do they make a big enough battery box to fit say a battle born LIbattery? And I have a blue sky solar boost 2000E charge controller. Do I need to change my controller as well?
Hi Will, great video and finally i found back the active cell balancers; in your hands! LOL.
Could you share the brand and type?
Would you use this ones in a mismatched setup of 16 lifepo4 cells?
I don't know if there is a central intelligence that controls this kind of separate balancers.
By the way, I use a Batrium bms that's really nice.
Would appreciate a bit quicker respond on my support question mails though, but that's another story.
Good man!
No bms on my 18650 new lithium ion Battery too !
Balanced once everey 6 months.. for Nothing..
On my 230Ah, using 0.5C discharge, Max.
👍🏻
Will, could you please pull apart and review a Greenlife, 100AH battery? thanks love your channel. I would also point out to you that your audience is not just home and camper solar enthusiasts. I use your knowledge and learning to educate myself for using lithium batteries on my boats I am making and the company I am starting for next generation boating. You offer a lot in more areas than you know and I would recommend you expand based on that. Thank you.
I look forward to your video on the mismatched batteries with the active balancer. There's not nearly enough available knowledge on this subject around the interwebs.
good day from Philippines! hi will prowse my inverter has the same features of a bms (mpp solar hv2-5048) like overdischarge disconnect, low discharge disconnect, etc. and i have new and same voltage lifepo4 batteries. do i need to install bms on my 16s 48v lifepo4 batteries?
The only drawback with active balancer is "COST " that is why it is not widely used in BMS system, but saying it's useless is misleading.
Indeed, it works great, I use 3 of them and they works fine for years and do proper balancing of my Winston 200 Ah cells.
Looking forward to the active balancer use case videos! Will, could you do [or have you done] a video on wind power? It seems like everybody focuses on the particulars of the turbines, but I figure there's back-end considerations (dump load? turbine stop?) that could be addressed, even if you're not in a windy area.
BYW - glad you’re feeling better
I bought 4 band new 90ah lifepo4 batteries and they all have matching ohms and all came at a perfect matching 3.33 volts on all 4 batteries.
I didnt bottom balance them bc they seem so perfect. I began charging them and right away they charged totally unbalanced. Literally 2 were 3.37ish. One was still 3.34ish and one reached 3.65....... like. I don't see how they would last a month
The issue I have with 'normal BMS' is that they normally start doing 'cell balancing' only AFTER the battery is completely full.
So if the battery is say 80 of SOC, the BMS will not start to perform any cell balancing.
If my battery never reaches 100% SOC, then the cells will never be perfectly balanced.
This is why in my applications (Li-Ion ) I prefer to have a way to decide WHEN to start doing cell balancing
Balancing for LiFePO4 isn't that important..less so at our c rates for solar. We need to balance cells every six months or so. Watch my videos on cell drift. Yeah for nmc and li-poly you need more balancing with small packs and higher rates, but a BMS can balance fine
The engineers are not idiots. They provide enough balancing current for typical cell drift over time. And balancing at high soc means higher voltage and faster balancing. It's more logica to top balance than bottom balance in most instances. I don't see what the problem is
Question, Your video of March 6,2019 creating an 8 battery 24V system. If that is configured in a 12V, 8 battery system, will One or Two BMS need to be used? Or can you apply the single 8 battery BMS ?
Excellent video -- and nothing caught fire... we ONLY use Active Balancer when the battery is USED from another work/job site and the voltage is still really off AFTER we bottom balance ...
Exactly! That's a smart application. Very cool
Güneş panellerim için 10 adet 12 Volt aküyü seri bağlayıp 120 volt elde ediyorum yalnız nasıl şarj edebilirim bataryalar için ne tür bir sistem yapabilirim
Bir solar şarj regülatörü (SCC) satın almanız gerekir. İşleyebileceği maksimum solar voltaj ve akıma göre bir SSC seçin. Giriş Voc özelliklerine bağlı olarak, onu panel dizinizin maksimum Voc'u ile eşleştireceksiniz. SSC'yi panellerinize bağlayın. SSC ayrıca 12, 24 veya 48V pil kombinasyonuna da bağlanır (bunları seri olarak birleştirir). Böylece, ssc'nizin eşleşen voltajını elde etmek için 10 pilinizi (seri/paralel) düzenleyebilirsiniz. Umarım bu yardımcı olur.
ty
Im wondering if Will, have found a rebranded version of the renogy 100 amp hour battery?
Yeah they're called "Virtually any Chinese made Battery on AliExpress" .. Thats where Renogy gets their stuff .. and then rebrand
There was that one "glue bomb" version that was very disappointing.
Pretty much sums it up...why bottom balance cells, to have a bms attempt to top balance it later! That throws off the bottom balance!! Batteries are not perfect, & are supposed to drift apart on the top end for a bottom balanced pack...the opposite is true for top balancing. Bottom balancing is less stressfull on the battery & makes it easier to revive a deeply discharged battery. A smart charger should stop the charging process once any cell is 85%-90% max, or a programmable bluetooth board that stops the charger once the cell hits the desired voltage, which should also stop the discharge when a cells hits it programmed low, & not rely solely on open batterry voltage readings for safety cut offs....that will cause problems on a unmonitored battery over time.
I can theorize that bottom balancing at 20%-25% would minimize unexperienced failure, & would lessen the cell voltage drift once at 90% max, for those who charge that high. But its more important to keep from over discharging.
always worth watching
Hi Will, love your videos,....Have you ever looked at these 2 BMS's? 123BMS from GWL i think and SBMS0 from Elecrodacus??? Would love to see you test them for a 4s setup...thanks
What about Ians balancers?
6 cells of Yinlong LTO as a start battery in my V8 truck pretty sure i'd want a balancer