I still love the JK-BMSes in all forms and think there is nothing better out there in this DIY segment. You can of course go Batrium, REC or other fancy BMS. But are they any better or just more expensive? If you dig into the forums, you will find similar and other issues with all these other brands as well. But, here is my main concern about the project, and I don't mean this in a bad or negative way but want to be honest here, raise awareness and trigger some thought processes: Building such a battery system on a boat in a very harsh and aggressive marine environment... a DIY battery will fail more or less quickly. Example: there are far too many connections where corrosion can occur and make your system fail. The system, your life and safety rely on. Instead of a DIY battery, the cells should be in an air and watertight steel container, correctly compressed and have welded flexible bus bars. So, even if the battery is half under water, it will still work. And a DIY battery will not fail on a sunny morning on a dead flat sea, it will fail when you need it the most: in the middle of a storm far away from shore. Cruising on lakes, canals or even shoreline might be OK but crossing an ocean with a DIY battery, system and an Adruino-controlled throttle, I'm not sure if this is how marine safety is supposed to be. A JK-BMS might be the more reliable component in this setup...? For sure there are systems out there which have been used on boats for many decades which can handle such environments and have proven reliability. I totally love the DIY spirit of this channel but I have the rising fear, that you will be constantly fixing things and sacrifice your safety. You will be relying on a DIY system which is not designed for what you want to use it for. And moreover, the safety should be your very very highest objective of this whole project. Remember, when you got in contact with me the very first time AFTER blowing the fuse of your battery? We both raised awareness of safety in our videos afterwards. With this boat project, please stay very safe and plan well ahead BEFORE a blown fuse (or worse) reminds us about safety again. Stay charged and safe, my friend! Love your work.
Oh, you're right about the other BMSes being a trade-off of quality. A friend uses REC with ... modest happiness. The comments about DIY on a boat are also very fair, and the rather extensive time I spent on the flexible bus bars was because of just this concern. There's a couple concerns that drove me to the DIY route, despite all the concerns you raised being absolutely valid... First is that there's no pre-made batteries efficiently packaged to let me get the capacity I need into the space I have. Once of the key things for me is to be able to run canals/rivers with the mast down, and to do that I just need (relatively) huge raw capacity. Now that said, one of the reasons I've been so keen to run (now) seven separate, fully contained packs is because I do expect failures to happen, and absolutely at the worst time possible. If such a thing happens, I can either turn off the switch or unplug the Anderson connector and isolate the faulted pack with 1/7th lost capacity. Similarly, having two motors, each with a dedicated controller and cooling circuit, gives me full redundancy there. On the helm; I had originally been planning to go with Raymarine or Garmin for most of the the controls, navigation and sensors. Talking to many owners of all the different systems (inc. B&G and others), a very common complaint was them failing, and then being stuck because only certified techs could access / repair the system, and/or waiting (sometimes for weeks) for parts to arrive. I know that DIY'ing the helm controls comes with it's own set of risks, and one way I am hoping to help mitigate that is to make it an open-source platform... If others find it interesting, then hopefully "many eyes will make for shallow bugs". That said, even from this very early prototype, notice the little red switch hanging from the breadboard? That's an "oh shit" switch. Press that and the throttle gets set to neutral, no matter what the handle is set to. The helm will also be setup so that any input from the helm overrides any other command, so the helm is always "the source of truth" for control inputs. The ABYC (standards body) requires on electric boats a kill switch at the helm, which I will wire separately to open the motor contactors in an emergency, too. The key thing for me is the ability to repair things myself, no matter where I am. Doing this requires I DIY, which adds risk of course. On the balance though, at least if something breaks, I have a chance to fix it. If a commercial system breaks, I'm locked out and helpless. There's no perfect option, but for me, the choices I am making always have safety and repairability as the very top concern. And to be very clear, I read what you wrote as being from a place of concern, and I am touched and appreciate it. ^_^
Perhaps on your pre charge resistor, you can put an alarm buzzer circuit driven by the voltage difference across the resistor. So the buzzer could buzz for you until the capacitor is charged.
@@TheDigitalMermaid it might be easier to put a light, but I think you probably want an annoying buzzer to remind you. Think Jurassic Park when she's resetting the fences
I am always amazed when I hear about boat insurance in North America. In Denmark, there is no evaluation of qualifications, no surveys or any problems getting a boat insured. You just shop for the cheapest/best one and they'll ask you how much it should be insured for. And it's not like there haven't been any major storms lately that have caused them to pay out. Also almost never any trouble when you need to collect on claims. I've never understood that big difference. Note: if you are asking for insurance on a 50+ new/expensive boat, it is different, but not for "small" old boats like ours :-)
Hi Maddy, another great video. I started looking at your videos when you were trying different test on buss bars and I immediately liked your stream of thought on process and reasoning. I was nice to see somebody looking at the unknown like me. It kept me coming back to where you were at and when you started on the boat my initial thought was "well I'm not into boating this wont interest me" . Well my brother in law has a sail boat "out of Kingston ON" and I figured what the heck I will watch this one and again I was hooked on the way you tackle situations and learning about the nautical stuff. and now going into the drive/ electrical that i'm interested in. All that to say you are awesome and keep up the great work, or you might consider playing.
Hi Maddy, good you are pointing out that in Marine stuff things might be life threatning if somethings go wrong. If you might end up using 2 sides of the boat with 2 seperate banks you might want to have different BMSes, and maybe another inverter (might be spare). The same as you are opting for 2 engines. Take good care and good luck with your build!
Space and weight becomes a concern on a boat as small as mine. I'd love to hit that level of redundancy, but it's not feasible. However, having done all this work to build her, I am pretty confident that, with a proper spares kit, I'll be able to fix most anything underway.
@@edwardvanhazendonk Ah, in my case, it's kinda like 7x 1 bank, the only common connection is the bus bar they all go to. Each battery is fully self-contained; it's own BMS, it's own T-class fuse, it's own disconnect switch and it's own anderson connector. Any one pack should be trivially easy to isolate, if needed.
I put a LED diod and apropriate resistor in parralel to charge resistor. You can see how fast LED fade out. In les than a second. In case charge resistor fail then LED fades out very slowly.
@BreatheScotland If there's a fire, I've got (currently) three fire extinguishers. If those aren't enough, a life raft. However, the highest risk of fire is a bad electrical connection... Which is why I spent a LOT of time working on the ideal flexible bus bars, and why I'm over-sizing wires (goal of
U can use a timer for the precharge resistor. push button + attiny(measurement of time or difference in voltage) + relay or MOSFET(for precharge resistor) + bistable(latching) contactor (example:DCNLH200PD24). This can be switched remotely, and when adding a current shunt, it can even serve as a protection against a short.
Yea for You!!!! Tell em like it is for Battery Protection Systems. BPS, BMS's are Battery Management Systems whereby they attempt to Manage the charge state of individual cells.
To have redundancy with the limited over all charging voltage by the charger and to have a additional active balancer (activated above 3,45V) and to have the BMS on top of that is safe, even, or better specially if its a JK BMS.
Nice video. We had a lot of snow as well fortunately not now anymore :) Good luck with your project ..it is the thing that takes the most time..to debug things
@@TheDigitalMermaid haha yeah..because you fixed some problem only you knew about and it is finally working ..what ever it was that was stopping you :)
The good people keep their front yard free of snow! 😮😅 I want you to succeed to convert your boat to electric drive. And you will - if not you, who else? You‘re so strong.
I use an LED across the momentary switch to the resistor for a light in my face that’s telling me there’s a voltage difference issue here. “Hold button down till light goes out before closing switch “ is printed above the lamp. I found that LEDs that are rated for 120v ac (Amazon) will work AND not override the discharge resistors on the inverter’s capacitors. Most LED+ resistors will keep the capacitors charged, not what you want when you want the inverter dead.
Good timing for me. My engine control is so low to the floor, that I have to duck down in order to move the control. I was thinking about using a stick connected onto the control(which i have seen), however, i wanted to use electronics to give me more options. Looking forward to seeing the experiment.
My controls are so damn hard to reach... I find myself often reaching through the wheel, which is never a good idea. I can't wait to have the new throttle setup!
Ideally we want to measure the internal resistance of each cell that goes into creating a battery bank in series. You want them to be roughly very similar. If there is a mismatch, you may start off with all cells top-balanced, but as you charge the battery system, the cells with higher internal resistance will dissapate more of that power in heat and not as charge. The power loss is designated by P=I^2 x R, the current flowing thru is the same for all cells, but R is the internal resistance of each cell. Hence the power loss in heat produced by each cell will differ slightly based on their internal resistance. And for this reason, the State-Of-Charge (SOC) will drift out of balance overtime if you have a battery pack with a high mismatch of cell internal resistance. So what you have mentioned having a BMS is absolutely correct, either passive balancing or active balancing, this functionality will be required to maintain a good health for the LFP battery pack. If the SOC of the cells are not the same, as the battery gets charged, the cell that reaches full charged can no longer take on more charge. The only way is to dissapate the energy as heat and it will heat up a lot more than the others that can still take on charge. OVertime, this will significantly reduce the lifespan of the battery pack.
They were all matched at the factory when I ordered them. Of course, the IR changes with the SoC, so IR matching is only so good in the end, but agreed, do your best.
I have watched several of your videos and like the content so far. I also am a huge fan of Andy and the Off-Grid Garage. I had a thought when watching this video when you stated be out in the water away from shore. I also watch another youtuber that spends much of his time on a sailboat. He has a device called a bank manager. Allows you to mix lead and lithium banks. I understand you have 7 48v lithium banks which is amazing. I also understand you are planning to move to all battery power for propulsion. All that said I like to think through backup plans as I have learned in my life that sometimes "Murphy" is an optimist. Meaning even things that should never go wrong sometimes do. That said I am not sure if a backup generator is an option. not sure if using some sort of alternator or anything of the like as part of the plan. The bank manager that Clark has developed is of interest to me. I am planning to get a bank manager and try it out with Lead and Lithium on an RV. He also has some videos on a DC powered Air Conditioner. these may or may not be of interest but thought I would see if you are aware of Emily & Clark's Adventure th-cam.com/video/sqT27KbxRec/w-d-xo.html .
Loving the white fluffy snow, unfortunately where I am we got the mostly water snow. So the plow row was not so much fun. Anyway, KW looking fantastic.
It's really pretty here! That big branch that came down was from the wet kind of snow... We had a good bit of snow, then it warmed up and turned to rain. The snow got super heavy and broke the branch before it melted. Ah well, such is life in Canada
Grew up in KW, we got some real snow back in the 70's. I had my first thundersnow experience there, although no one believed me. Still, I'll take a good healthy snow over the constant threat of ice rain we have now.
Question: Do you plan to keep the boat on the hard until the conversion is done (or ready for testing)? If so, your broker could negotiate a policy that protects your boat on land while you work on it, with the understanding that you'll renegotiate for a policy that would start when you hit water. Maybe they wouldn't mind insuring a boat that is just being worked on. And that buys you some time, and you'll have something to show for all your work, which could convince the insurance company that your new electric boat is insurable.
Partly, yes, and I asked about that. He was saying that they might worry about things like welding or whatnot (why they don't want to cover during the conversion work). I explained that I had no plans to do welding in the boat, and that I am well aware of the risks of things like oily rags spontaneous combusting and would take appropriate measures. I also said that I am happy to agree to not do certain work on the boat if that would allay the concerns of the underwriter. He's taken all that back and he's doing his thing now. The current goal is to get the motor in and the new wiring done and signed off ASAP. The boat will NOT be done when I go in the water, not even close. Heck, there's a good chance the old rod rigging will go up for one more season. The goal is to splash and start sea-trials as soon as I can.
Hi, Still was thinking about a comment about your head scratching problem of the last video...and you put up an other one... your fast:)) About your fastness but concerning the pre resistor thingy there a simple solution might be to look at a different kind of switch. Or better two switches with removable keys. But using only one key for both switches. One switch is just for the loading through a resistor to load the capacitor. when that is done, switch it off, take out the key and use it for the main switch. This way you build in the seconds you need. And after a disconnect is needed, and put the key back in the preload switch. The setup of 1 key for more battery switches which dictates the use, connections and possible problems is also handy for more battery boat related switching stuff, Like preventing flyback on alternator switch off, combining, separating or directing banks/power to certain equipment, like in an emergency use. As for insurance, i would like to know what the Electrical Boat Associations of America en Canada, as well as the Sail Canada body as the Office of the Superintendent of Financial Institutions (OSFI) has to say about that. Because if insurance companies make fossil to electric conversions, in a time of climate change and energy transition (think big here) practically impossible for boat owners this is and will be a big issue.
The key idea is neat, but I can't ignore complexity... what if I can't find the key? I think the cover over the switch is, for my use, the best combination of simple and reliable. Adding a buzzer as others suggested might be a nice addition, have it buzz when the lid is lifted, and stop buzzing when the desired voltage is reached would be a great reminder to wait a minute. On insurance, as mentioned, I think insurance companies are starting to understand that electric is the future, and they have to get onboard. Marine / sailing _everything_ is slow and resistant to change. I'm hardly the first conversion, but it's still pretty rare these days. That's going to change though.
@@TheDigitalMermaid There, you made made me smile again:)) Complexity is just for those that do not (yet) know how. Like a mason will find a solution in brick, the carpenter in wood to solve the same problem. Well, and since i am a more creative guy, i would suggest or make myself, to solve the "what if I can't find the key?" question with: make a bit deeper frame with glass of 15 x 15 cm, (like the fire alarm buttons boxes) hang as much keys in there as will fit, paint it in any color you want, and hang it in reach on a bulkhead. No power needed, well protected in heavy seas and always usable. :) And regardless, those "what if" questions you ask are always good questions to ask specially in risk management. As for insurance. I did make some calls here in the EU, and 90% of them state that, any conversion to anything is allowed and insured while work is done under the old policy, and when finished the result is checked and signed (and payed for by user) by a certified company and will result in a new policy contract. Sadly none of them will insure owners outside the country or EU. The one that do, are Pantaenius.com, headoffice in UK. sponsor of sailor Skip Novak (se here on YT) or the marketplace Loyds.
Well, you mentioned safety. On that note, when you do get back to battery building, please drill your attaching hardware and lockwire it. We use it in aviation (my industry) and i also see it a lot in motor racing. Key point - constant movement, flexing, continual impacts will end up with things coming off (im thinking slapping against waves for days and days... those forces add up). Big current involved with those banks now equals potential arcing and fire with loose battery connections. Last thing you want (ironically) when at sea while surrounded by only water. Once you have drilled the hardware, practice putting it on so when the nut tries to unscrew - it tensions the lockwire and cant come off. Have seen too many lockwired back to front and it will get loose. Anyway, future consideration. Its a pain sometimes to do... but we use it in aviation. All our rules arent just written in blood, its graves (many unmarked). As you say, you cant just pull over and get help. Take this advice as you please. And bonus credit for Kepler. He had much valuable contributions :)
Oh if I could somehow reliably drill a hole in the battery posts so that I could get seizing wire in, I totally would! The concern for movement is why I put so much time into coming up with the flexible bus bars... I may splurge for the final build and get nordlock washers and fresh posilock nuts, as the next best thing. Periodic thermal checks with the FLIR will be part of my maintenance routine, also.
@@TheDigitalMermaid for the amount of money you could spend on posilock nuts and the like, I have no doubt you could engage the services of a local engineering firm / machining shop for an hour or two who could expertly drill the posts for you. Would just require hauling them there and back in batches perhaps?
I'll get through the first season / sea trials, and see if anything shows signs of moving (witness marks). If anything does, then I might just do that. The idea of machining so near the cells of the batteries makes me nervous, so I'd want to know the effort, risk and cost was worth it. If I don't, annual maintenance will be checking all nuts.
Aye, I admit I kinda phoned it in, but as I mentioned the dayjob has me super busy. I've got the helm video half done, so the next one will be more doing and less talking.
Hi Im new here. Looking forward to the upcoming venture. Uncommanded vehicle movement claims..... I've always have inexpensive test lights in my kit. The inexpensive ones just have a an incandescent bulb rated at system voltage. So, they are generally rated at 12, 24,48 and so on and are relatively low wattag. I find them useful because the brightness intensity indicates both current and voltage which speeds testing along multiple contacts. Since they're always available at hand I've never used a pre charge resistor. By using the test light instead, I can see the light intensity come on then off to dark which is a positive indication that the charge happened timely and completely. I had an 18 volt LiFePo4 battery pack EXPLODE recently. It had been reliable for ( 8-12 yrs maybe?), hundreds of hot and cold cycles to dead. Anyway it finally let go. It had been out in the cold probably partially charged and with winter coming on strong I had decided to stick in the chargeer mounted on a timber post in the shed. The charger didn't indicate undertemp but instead went to charging the pack. It was some time later, maybe 6-12 minutes that I got shocked by the sound; it was a loud sharp crack like a small cap in a toy followed by a loud his for nearly a second. I was shocked, sorta like when the electrical arc happens; it kinda stunts you for a split second but it's very real. My mind flowed full of concerns regarding fire as my eye spotted a gray plume erupting from the pack like steam. The explosion plume engulfed an area greater than a postage stamp and the cloud arose up nearly a finger length. My decision was to immediately disconnect the charger plug ftom the supply outlet. That really calmed me down snd I listened closely for what I think could've been a sizzling. It wasn't really sizzling I thought, so I touched it and it was cool. That pack is still sitting right there on the bench. Anyway, I popped in the next pack and got a low temp indicator. I warmed the charger, pack, and remaining packs then charged them fully without any problems. Looking at the exploded pack there was no external damage and no signatures of heat, so probably just one cell ruptured. It would be interesting do do some more destructive cell testing and predetermine the best enclosure, venting, and serviceability. 👶🏻🚬 I think in the spirit of experimental transportation one should protect others with liability insurance, self with health care, and asset protection by not experimenting. Probably divide the assets and coverage limits/types. What will one of these cells do at 48 volts?
The light idea is something I was leaning towards, but someone else suggested a buzzer the goes off when the desired voltage is reached, and I really like that idea, so that's probably what I'll do. At the end of the day, anything that stores any kind of energy sufficient to move a vessel comes with some danger, same is true for diesel, gas, lead acid, etc. As with all tools, care has to be used to use them safely.
@@TheDigitalMermaid Yes, I agree. I suspect that the LFP venting system is adequate outside of an enclosure. Probably the flame front is mostly self extinguishing so unless high pressure fuel is spraying on it there is just the matter of direction of pressure away from structure and person. The hall sensors of esc motors should be sufficient to limit most un-commanded movement in most boating applications. Generally, I think sometimes technology can be unnerving when we are surprised by an unforeseen fault which gives way to a deeper appreciation or understanding. I love the fast reliable nature of an electric drive going forward and in reverse.
If you saw the breadboard in the video, there was a little red switch hanging from it. That's an "oh shit" button, when pressed it forces the motor into the neutral position, stopping the motor no matter the throttle position. Later I plan to have (as required by ABYC) an emergency kill switch that will shut down the motors directly by commanding the contactors to open.
I have a 36" soft bristled horsehair Floor BROOM with an extra long handle for BROOMING Off any Snow that accumulates on my 30 panels on a 45 degree angle ( PV Panels ) the Final SIX (6) Panels are 180 degrees (vertical ) I do not attempt to "clear" my 700' gravel driveway COOP ...
on the plus side,you are not totaly stuck waiting on incurens, you have projects you can keep working on. But a bit of a roadblock to be sure. Hoping for the best.
While I completely understand your position on JK-BMS it should be noted that they have come out with a new firmware that would prevent overcharging in the default mode. As for the upcoming videos, I'm am fairly certain that most of us watching are nerds of one sort or another and the credo of most of us is that more knowledge is good so try not to worry so much about weather we're going to like it. I know I will...
Being conservative on how you use batteries is good. Sailing is risky enough without adding additional risks into that equation. You are right that a car or house is a different use case.
The problem with being the very early adopter is that you are a guinea pig. Sometimes it is better to take the second taxi off the rank. Keen to see if Andy the JK guinea pig will end up with the ideal 48v lifepo bms. Better to be a happy second rank adopter than the sometimes first adopter Victron gear looks good but is very expensive.
Trick is that JK isn't really a new player to the BMS space though. Their development methodology is "most features or least money", and clearly it works for them.
Well said about JKBMS on a boat. I don't recommend them on a boat as well even the new ones that are parallel capable. They have not proven themselves in the field.
I look forward to "The Nerdy Bits"(tm). Having built an EV "racecar", I'm curious about your motor and control setup. The HPEVS AC51 we used wants to run at a rather high RPM (for a car). We drove it like a normal car - 2-3k RPM - and it quickly overheats. Spin that puppy up to 5k+ and it'll run all day. (it is based on a low voltage hydraulic pump motor.) Like everyone does, we use a Prius throttle peddle. I don't know if there are any drive-by-wire boat throttles. If you took the spring out, and used a fwd/rev switch, the prius throttle might work.
for the helm /throttle have you looked in to a solid state solution so there are no risk of corrosion. potentially with a magnetic rotary position sensor have had good luck with a AS5600.
Huh, that's interesting... So you rotate a magnet over the IC? The pot I've got is sealed, save for the pins. So I'm pretty comfortable corrosion won't kill it particularly fast (and I'll have a spare), but that is an interesting option. The trick I suppose would be to pot the board, unless I wanted to trade one issue with another. :)
yes just rotate a magnet over the IC. but yes you would need to give the smale bord 25x25mm with the IC a dap of epoxy and then you can communicate with it over i2c and pick between Analog out / PWM / I²C as a output. but if the pot you already have is sealed you should also be got.
bms is a must AND active cell ballancer is a must, not recalling the brand i used as it is not important and probably not for your battery in your boat as this is in a rv, but when thew battery had down time i.e at night the cells have time to reballance, and the ballancer turns off so it is not a draw on they system when it reaches a ballanced state.
I know from experience that you absolutely can run Li-ion batteries being charged in parallel with only conservative pack-voltage cutoffs for years, and it works great. Then they catastrophically fail.
And that's just it... "But it worked for years!" is the common refrain of someone who just suffered a catastrophic failure. Heard it countless times in my past life's work.
I think that's an entirely reasonable temp. I suspect that I'll turn on the heater in my setup when the engine/battery bay gets into the single digit (c) temps, but I'll need to do experiments to see at what temperature does the extra energy / cost of heating cost makes it worth while.
You nailed it again! I am really keen on seeing you go through programming the arduino; what language you will be using - I know nothing of arduino's though I have thought of getting one to play around with. You will probably tip me into it - what a channel!!! Tom
Thanks, Tom! Arduino is C++, and it's IDE makes it really easy to get into, as it masks all the firmware flashing and whatnot that can make it hard for new users. Cheers!
I do not miss the snow from back home haha. We have an M3LR, in a warm climate. How do you like it where you are? Just keep it topped up so you can keep the cabin warm? What year? I hope newer so you have a heat pump heater and not a resister :D
I've had no issues with the MYLR, the range loss in winter is easy to offset by just slowing down some, though honestly that doesn't even cross my mind unless I'm driving for a few hours at least. I think mine does have the heat pump, and I'm even toyed with the idea of buying a spare one for use on the boat... :D
There is a bigger problem with systems that communicate and are controlled by the bms. This was a big part of the problem with the wrong bms settings. So if charger/ mppt solar are controlled by the bms they can very easily overcharge. See victron DVCC. Heat in the wires is counted in the result because the current is the same in the loop (current doesn't run away).
I come from a Linux (unix) background, and I've really come to love the design where each piece worries only about the piece below it and above it, nothing else. Trying to have a master systems that tries to understand and control everything is ... complicated.
They're my insurance of last resort... I know they're really hard to make a claim with, and some marina's won't let you in if that's who you have for insurance.
I cannot believe that you (we) are still debating the BMS requirement thing. Please simply do not acknowledge the comments and focus on what is really important. Keep up the good work!
those red battery disconnectors what are they rated for? It took me a bit to find ones that are rated for 60V. Contact Blue Sea systems and see if the ones you have have been tested for 60V( over 48V).
They're rated for 300A continuous, 500A peak at 48vDC, as you saw. In my experience, everything marine that's "rated for 48v" are good up to 60v, as the "48v" is more of a class rating. I suppose it wouldn't hurt to confirm, but I'm sure it's OK.
HOWdy T-D-M, ... cold - Cold - COLD outside ! "0" F degrees = ( --18 C degrees ) but sun - Sun - SUNNY too = my BATTERIES are ALL @ 100% SOC at 12:00pm NOON 🙂 Thanks for POSTING COOP the WiSeNhEiMeR from (frigid) Richmond, INDIANA, USA ...
pretty ok news about capacity .. just let that pack get older and feel ok with its rate of degredation !!! you have the privilege to get older in so much lower rates and you are going to try even more new energy storage chemistries!!!
Aye, I knew when I bought the cells early that I would lose some life in the batteries, and watch the prices come down. Oh well, I've learned so much in the time in between that it's still worth it.
I think I mentioned the updated firmware, by version actually. My concerns remain, not because of this one bug, but because of multiple issues I've had with them.
Going too low on LiFePO4 is not as harmful as going to high, you do not want to go over 3.65 or worst case 3.8 but that is causing damage. I accidentally went over 4.0 on two 200Ahr cells and they puffed up badly, tho still work they are only 80% now and probably won't last so i don't use them now. They are so puffy they won't fit nicely in the case. So over voltage has no room for error, under voltage from 2.0-3.0 will not hurt them as you know, below 2.0 might not be good either. Same goes for other types too. Over charging is damaging of the cathode and causes gassing for all types of cathodes, they have no tolerance for excursions on the high side.
Huh, good to know about the over-voltage. Another person here said they're going to see if they can test over-charging a cell to see what happens and at what voltage.
I do, and I almost bought one. My lawn mower is electric, too. The reason I didn't bother with the snow blower is that I know I'm leaving soon to live on the boat, so it was hard to justify the expense.
Why don't you acquire prebuilt EV pack batteries that are essentially weather sealed? I'm purchasing 3 packs, each 35kwh sealed and epoxied together. I can just drill a few holes and run the wires outside and then seal the holes up to prevent water from getting in. T hey have a strong casing and the base of the case is a rrigid metal platform, they will survive marine movement.
Two major reasons, and a two important reason; 1. Most EVs use NMC cells, which combust on thermal runaway. LFP cells don't, but exceedingly few EVs in north america use them yet. 2. EVs need much higher power motors, and so they run at much higher voltages (200, 400 and even 800v). Using high voltage on a boat is a lot harder given ABYC requirements, so staying under 60vDC makes things safer and easier to meet regulations. 3. I Need to know that I can repair the system myself. EVs have closed controllers so if they fault, I can't do anything to reprogram/fix them. Same for the batteries. 4. There is virtually zero EV charge points in marinas, so one of the biggest advantages of an EV pack, high speed DC charging, wouldn't be available to me anyway.
Hi Maddy, have you come across REC-BMS? Very popular high quality external BMS over here in Europe. They have 48V models so you could build a monster 6p16s pack. Certainly no pre-charge issues with that! Talks Victron CANBUS so fully compatible with your Cerbo, Multiplus and MPPTs. Charge controlled over CANBUS but also has several configurable relay contacts to force charger and load cutoffs based on cell rather than battery voltage. Very well engineered BMS. Thanks for sharing your project. All very interesting 🙂
I have, and from what I understand, they're very good quality. I wish they had an active balancer and bluetooth, but so it goes. In my case, I really want to have the seven batteries each self-contained, so that a fault in any one only takes out 1/7th my total capacity.
Maddy, Just wondering what you main reasons the JK BMS you help up is in the not recommended list? Until last week’s fiasco my one JK BMS was the only bright spot… In general BMS are a bit of a horror show: Weak or un-useable balancers, inaccurate SOC integrators, unable to easily reset battery to full SOC, initial startup process after complete shutdown, etc. Daly, JK and Jiabada (and derivatives/clones/relabels, I tried them all) I looked at the Victron, but the complexity for a simple system appears too high. If Victron made a simple BMS with working balancer I would be the first in line. Their coms/Bluetooth implementation is stellar. Work of art. To me, my JK at least is the only BMS that can actually balance a battery that needs it. I’ll live with the other items. On the others I need external balancers and they introduce their own issues….. I realize the issue last week was a release test failure and it seems to have snuck through. It should not, and hopefully they fixed it. I put this on the catastrophic bug list…. But does it apply to the BMS you showed? Anyhow, I would appreciate your understanding of why you dislike your JKs? I could re-watch the videos, but I do not remember any problem you had that I did not see with the other BMS’s I used….. Thanks. Just wondering.
I had long been frustrated by JK, with their willingness to change features / capabilities without changing the model number being a big part of that. I could review a BMS and decide it's great, then viewers could order the same part number, and get a different BMS. That makes it almost impossible to recommend it. The most recent issue just underscored how little they care about safety, a separate and very bad problem. If you have a JK BMS and you're happy with it, great, but for me, in my use case, I don't know what other ways this thing could fail. I just lost my trust in it. In a sailboat, out in the ocean, I must be able to trust my safety equipment.
A fellow sailor i know, who uses a 16s LiFePo bank to power his me1616 told me he never had a bms. I asked why and he said the peak current sometimes is to high and his bank is almost never fully charged so the bms does not balance anyway. He checks his cell's on a regulair basis and top balance them every half year or so. He has been doing that for years with no problem and is all over the globe. His batterybank is also used as housebank, charged by a generator and pv's. I don't think it's smart so i am using a jk 200A bms in my build. Now i hear this is not absolutely safe also. What BMS is???
In the end, there is no perfectly safe solution. This is why I was careful to say in this video that I am talking from my point of view, and from my personal feelings of what is acceptable. While I disagree with your friend that "I don't need a BMS", disagreeing is not saying he's wrong, just that we've come to different conclusions.
Hello sorry its me. On the subject of a cavalier attitude to safty, have you a back up propulsion engine or do I understand it correctly you are going out to sea full electric?
I will, actually. I spoke about it in a previous video, I'm planning to have a 10kw and a 5kw motor, each with their own dedicated controller and cooling loop. After breaking down three times because of failures with the diesel, I want as much redundancy as I can afford (cost, space and weight). And yes, full electric.
@@garys-half-baked-offgrid-dream Yes, she's a sailboat first, these are auxilliary motors. That said, one of the key design goals for me was to develop an electric system that would let me run mast-down in canals, and I think I can do it. As I explained in the "Decisions Made" video, using a similar boat that was converted to electric using a similar motor, I think I can push at 4 kts in flat-calm conditions at ~2200watts, or at 3kts at 900watts if I really wanted to maximize range. With my usable 96.3kwh of battery, that translates to 43.7 hours at 4 kts (175 nautical miles), or 107 hours at 3 kts (320 nautical miles). I'll be able to recharge at just over 4kw on shore power, so I can recharge at ~2x ~4x faster than my consumption rate, giving me a solid two days of travel per night of charge, at 4 kts.
@@TheDigitalMermaid Like planning a PV system summer is easy winter is the acid test. Plan for broken rigging, heavy sea's with a head wind and the rest will be gravy. I know we got off on the wrong foot, I genuinly mean you no harm and wish you all the best with this venture you're braver than I. I watched Jaws at too young an age. Inland water I am fine out at sea my bum squeeks. Out of curiosity what's your plan on how to test your theoretical range saftly?
@@garys-half-baked-offgrid-dream That's why I am so focused on charging from regen off the prop... The solar generation is going to be bonus watts, basically. I want to sail to high latitudes and there, even on a clear day, generation is limited. That said, I'm hoping to get ~1000~1500w of solar. Part of why I chose the Landfall 38 is because the main boom ends a good 2 meters forward of the transom, so pleanty of space for a generous solar arch. The plan to range test will be to disconnect one battery and run the others from max charge to dead empty vaguely around the area of my marina, then connect the spare pack and use that to get back into port. Fairly easy math after that the figure out how far I could have gone on all seven. I'm also curious to see how the regen works on the 10kw vs 5kw, and at different speeds over water, to create a somewhat accurate graph or the real world regen. And no hard feelings on my end. I have my opinions, I speak those opinions, and don't mind at all if people see things different. All good on my end. :)
Hi Since you have multiple battery banks, should consider adding some redundancy to your system to prevent single point failures. Each battery has its own circuit breaker, eBay has lots of AIRPAX LEL Use multiple MMPT for your solar panels. Oversize high current wires. Use multiple DC/AC inverters, also reduces parasite load since you can turn of circuits Victron Inverter VE.Direct 250 to 1200VA If you are really keen multiple DC busses. For a salty environment use electrical grease on all your high current connections. Make sure all your high current connections are easy to inspect and fix. List of spares and tools. Multiple smoke detectors and electrical fire extinguishers.
The only chemistry on which you do not need a BMS would be LA or AGM, but they carry their own pitfalls.... Anything Lithium, you need a BMS, you might not need the Inverter to know what is going in the BMS eco system other than voltage but, you need a BMS....... If you use lithium and you have no BMS...... You are most certainly looking for trouble. The pre-charge.... Use a micro switch or micro leaf switch on your lid, when you lift it, the switch can close it's contacts, engaging the pre-charge resistor....... But, your choice.
Aye, BMS is a must in my opinion. I just don't want to be that person that tells others they're wrong. Up to each person to decide what's right for them.
That loose end about BMSs and that cell that gave trouble. Don't feel at all guilty about letting loose about JK because, in a number of ways, they deserve it. I just cannot fathom "oh we can easily put out a firmware update" as being an acceptable approach to quality management - just what happened to proper testing? Beyond that, I don't recall you telling anyone what to do with JK BMSs, only what you were inclined to do. About that dodgy cell. Was that not caused by the battery being left for ages - with the BMS still active? Would you actually do that if you lived aboard your boat? My guess is that you'd be watching batteries like a hawk. Even then, the worse thing a dodgy cell can do is to cause that battery to switch itself off - but don't you have redundancy built into your design? "Lose one" need not mean "lose all". I wonder too, if there's a case to be made to sail with a maintained spare cell, "just in case"? Maybe that means DIYers clubbing together to buy four and sharing them around. After seeing Andy build his "Frankenstein Battery", switching out a dodgy cell might be quite doable.
Heh, I didn't think I did, but some people got upset like I personally insulted them. Oh well, I clarified my position and if someone is still upset at me, so be it. Ya, I was running a (now aborted) parasitic drain test. It's still odd that the one cell fell so low while all the others (95 others!) were still happily at 3.1v. It was odd. In the end, this is also why I am building seven independent packs; Any one failure will only take out 1/7th my total capacity.
The thoughts you brought up about the JK BMS are valid in with your context. Your use case has a life-or-death aspect to it and the suppliers of critical components of your system should at the very least be honest and consistent about their products so that you can feel comfortable that your technical decisions will hold up if the proverbial shit hits the fan (and if you're anything like me, the shit ALWAYS hits the fan). Unfortunately, following your train of thought, you should stay from all Chinese products in general cuz I've come to realize its a cultural thing; there's something about the current Chinese culture that makes them dishonest when backed into a corner and combined with their atrocious English skills and their inability the admit wrong doing, continued use of their products requires a hope-for-the-best attitude and a read-between-the-lines discernment when judging the veracity of their not so good English. But where does that leave you? Aren't your batteries China made too? I tell you, the times that we live in are NOT easy.
There's some fantastic kit out of China, look at BYD for example. I think we in the west mainly see the cheap shit because, well, that's why we go there, looking for the cheap stuff. There's of course a big cultural difference, I'm not debating that, but I'm not keen to paint any country with such a wide brush. The trick is evaluating any one company on it's own merits and, as you mentioned, for my use JK isn't appropriate.
As yes, the quagmire of insurance... with a high power electrical mess you made yourself. I can see them all running screaming from the room. :-) They're worried your DIY setup could kill people, burn down a dock, etc. People legitimately have loads of concerns about safety. Even more so when it's something you built yourself. Factory made, factory tested that have someone to sue are a different matter. (still an uphill road, 'tho) If you can show them proven safety technology -- BMS, physical disconnects, fire suppression, fire limiting battery box(es), fuses, etc. (and a plan to deal with a fire) -- they may be more receptive. It'll be interesting to see how this goes. I'm sorry you have to be the pioneer here.
I saw a video going around where someone charged an LFP to 15v and it legit popped and caught fire. It wasn't a lab test, so who knows what actually caused it to go, but it wasn't pretty.
@TheDigitalMermaid I bet it wasn't good I've seen a picture off a ecoworthy battery in a really bad state split the battery in two nearly I would show u but can't on here they are pouch cells too lifepo4 was easily 3 times the size
@@davidhopkins9021 I've seen 8s LFP prismatic cells using rigid bus bars turn into bananas after being overcharged. They have an extremely low chance of catching fire, but the force they exert when swelling is pretty impressive/scary.
@@TheDigitalMermaid There are already a few that state that you can’t park your electric vehicle in your garage. Ignorance on the insurance company’s part.
I still love the JK-BMSes in all forms and think there is nothing better out there in this DIY segment. You can of course go Batrium, REC or other fancy BMS. But are they any better or just more expensive? If you dig into the forums, you will find similar and other issues with all these other brands as well.
But, here is my main concern about the project, and I don't mean this in a bad or negative way but want to be honest here, raise awareness and trigger some thought processes:
Building such a battery system on a boat in a very harsh and aggressive marine environment... a DIY battery will fail more or less quickly. Example: there are far too many connections where corrosion can occur and make your system fail. The system, your life and safety rely on. Instead of a DIY battery, the cells should be in an air and watertight steel container, correctly compressed and have welded flexible bus bars. So, even if the battery is half under water, it will still work. And a DIY battery will not fail on a sunny morning on a dead flat sea, it will fail when you need it the most: in the middle of a storm far away from shore.
Cruising on lakes, canals or even shoreline might be OK but crossing an ocean with a DIY battery, system and an Adruino-controlled throttle, I'm not sure if this is how marine safety is supposed to be. A JK-BMS might be the more reliable component in this setup...? For sure there are systems out there which have been used on boats for many decades which can handle such environments and have proven reliability.
I totally love the DIY spirit of this channel but I have the rising fear, that you will be constantly fixing things and sacrifice your safety. You will be relying on a DIY system which is not designed for what you want to use it for.
And moreover, the safety should be your very very highest objective of this whole project. Remember, when you got in contact with me the very first time AFTER blowing the fuse of your battery? We both raised awareness of safety in our videos afterwards. With this boat project, please stay very safe and plan well ahead BEFORE a blown fuse (or worse) reminds us about safety again.
Stay charged and safe, my friend! Love your work.
Oh, you're right about the other BMSes being a trade-off of quality. A friend uses REC with ... modest happiness. The comments about DIY on a boat are also very fair, and the rather extensive time I spent on the flexible bus bars was because of just this concern.
There's a couple concerns that drove me to the DIY route, despite all the concerns you raised being absolutely valid... First is that there's no pre-made batteries efficiently packaged to let me get the capacity I need into the space I have. Once of the key things for me is to be able to run canals/rivers with the mast down, and to do that I just need (relatively) huge raw capacity. Now that said, one of the reasons I've been so keen to run (now) seven separate, fully contained packs is because I do expect failures to happen, and absolutely at the worst time possible. If such a thing happens, I can either turn off the switch or unplug the Anderson connector and isolate the faulted pack with 1/7th lost capacity. Similarly, having two motors, each with a dedicated controller and cooling circuit, gives me full redundancy there.
On the helm; I had originally been planning to go with Raymarine or Garmin for most of the the controls, navigation and sensors. Talking to many owners of all the different systems (inc. B&G and others), a very common complaint was them failing, and then being stuck because only certified techs could access / repair the system, and/or waiting (sometimes for weeks) for parts to arrive. I know that DIY'ing the helm controls comes with it's own set of risks, and one way I am hoping to help mitigate that is to make it an open-source platform... If others find it interesting, then hopefully "many eyes will make for shallow bugs".
That said, even from this very early prototype, notice the little red switch hanging from the breadboard? That's an "oh shit" switch. Press that and the throttle gets set to neutral, no matter what the handle is set to. The helm will also be setup so that any input from the helm overrides any other command, so the helm is always "the source of truth" for control inputs. The ABYC (standards body) requires on electric boats a kill switch at the helm, which I will wire separately to open the motor contactors in an emergency, too.
The key thing for me is the ability to repair things myself, no matter where I am. Doing this requires I DIY, which adds risk of course. On the balance though, at least if something breaks, I have a chance to fix it. If a commercial system breaks, I'm locked out and helpless. There's no perfect option, but for me, the choices I am making always have safety and repairability as the very top concern.
And to be very clear, I read what you wrote as being from a place of concern, and I am touched and appreciate it. ^_^
Perhaps on your pre charge resistor, you can put an alarm buzzer circuit driven by the voltage difference across the resistor. So the buzzer could buzz for you until the capacitor is charged.
Now that's a neat idea!
@@TheDigitalMermaid it might be easier to put a light, but I think you probably want an annoying buzzer to remind you.
Think Jurassic Park when she's resetting the fences
@@BobHannent I really like the buzzer idea, it's a great reminder to wait.
Pretty good idea!
I am always amazed when I hear about boat insurance in North America.
In Denmark, there is no evaluation of qualifications, no surveys or any problems getting a boat insured. You just shop for the cheapest/best one and they'll ask you how much it should be insured for.
And it's not like there haven't been any major storms lately that have caused them to pay out.
Also almost never any trouble when you need to collect on claims.
I've never understood that big difference.
Note: if you are asking for insurance on a 50+ new/expensive boat, it is different, but not for "small" old boats like ours :-)
In the US, it wasn't that hard either. I'm not sure why Canada is so difficult. >_
I have to travel to Utah to enjoy my snow shovelling. Very therapeutic.
It kinda is... Put on some music and get into a groove!
Hi Maddy, another great video. I started looking at your videos when you were trying different test on buss bars and I immediately liked your stream of thought on process and reasoning. I was nice to see somebody looking at the unknown like me. It kept me coming back to where you were at and when you started on the boat my initial thought was "well I'm not into boating this wont interest me" . Well my brother in law has a sail boat "out of Kingston ON" and I figured what the heck I will watch this one and again I was hooked on the way you tackle situations and learning about the nautical stuff. and now going into the drive/ electrical that i'm interested in.
All that to say you are awesome and keep up the great work, or you might consider playing.
Thank you for the kind words, Mike! ^_^
Hi Maddy, good you are pointing out that in Marine stuff things might be life threatning if somethings go wrong. If you might end up using 2 sides of the boat with 2 seperate banks you might want to have different BMSes, and maybe another inverter (might be spare). The same as you are opting for 2 engines. Take good care and good luck with your build!
Space and weight becomes a concern on a boat as small as mine. I'd love to hit that level of redundancy, but it's not feasible. However, having done all this work to build her, I am pretty confident that, with a proper spares kit, I'll be able to fix most anything underway.
@@TheDigitalMermaid not 2 times 7 banks but 2x 3 banks and 1 household bank, but I see your point. 👍
@@edwardvanhazendonk Ah, in my case, it's kinda like 7x 1 bank, the only common connection is the bus bar they all go to. Each battery is fully self-contained; it's own BMS, it's own T-class fuse, it's own disconnect switch and it's own anderson connector. Any one pack should be trivially easy to isolate, if needed.
I put a LED diod and apropriate resistor in parralel to charge resistor. You can see how fast LED fade out. In les than a second. In case charge resistor fail then LED fades out very slowly.
@BreatheScotland If there's a fire, I've got (currently) three fire extinguishers. If those aren't enough, a life raft. However, the highest risk of fire is a bad electrical connection... Which is why I spent a LOT of time working on the ideal flexible bus bars, and why I'm over-sizing wires (goal of
hi....it's fabulous to see your videos...congratulations
Thanks, Nunzio
Yey! Shovel workout :D that's what was my morning today too :)
Good exercise!
U can use a timer for the precharge resistor. push button + attiny(measurement of time or difference in voltage) + relay or MOSFET(for precharge resistor) + bistable(latching) contactor (example:DCNLH200PD24). This can be switched remotely, and when adding a current shunt, it can even serve as a protection against a short.
Ok see this is how my helm is how my boat's going to have so many little computers... :P
Yea for You!!!! Tell em like it is for Battery Protection Systems. BPS, BMS's are Battery Management Systems whereby they attempt to Manage the charge state of individual cells.
In the end, so long as something actively moniors and protects the cells, it's good imo.
Enjoyed the video. Thanks for sharing
Thanks for watching, Lou!
To have redundancy with the limited over all charging voltage by the charger and to have a additional active balancer (activated above 3,45V) and to have the BMS on top of that is safe, even, or better specially if its a JK BMS.
Nice video. We had a lot of snow as well fortunately not now anymore :) Good luck with your project ..it is the thing that takes the most time..to debug things
Aye, and debugging is oddly fun. Stressful and annoying, but once you fix it, that little rush of happiness is addictive. :D
@@TheDigitalMermaid haha yeah..because you fixed some problem only you knew about and it is finally working ..what ever it was that was stopping you :)
The good people keep their front yard free of snow!
😮😅
I want you to succeed to convert your boat to electric drive. And you will - if not you, who else? You‘re so strong.
Thanks, Peter! That said though, I honestly believe far more people can do things like this, and I want to help encourage them to try.
Agreed, Madi is awesome.
@@hendersonsobers396 ^_^
Can honestly say I've never seen a timelapse of snow shoveling... Which seems like a natural fit for a timelapse really
hehe, I was like "oh man, I need to shovel again... Hey, lets turn this chore into b-grade post-roll content!". ^_^
I'm so excited about seeing how you tackle the helm!
So am I! I don't even know what I'm going to do yet. :D
I use an LED across the momentary switch to the resistor for a light in my face that’s telling me there’s a voltage difference issue here. “Hold button down till light goes out before closing switch “ is printed above the lamp. I found that LEDs that are rated for 120v ac (Amazon) will work AND not override the discharge resistors on the inverter’s capacitors. Most LED+ resistors will keep the capacitors charged, not what you want when you want the inverter dead.
This would work fine, ya. Someone suggested a buzzer working basically the same way, and I really like that idea, so I am probably going to do that.
Good timing for me. My engine control is so low to the floor, that I have to duck down in order to move the control. I was thinking about using a stick connected onto the control(which i have seen), however, i wanted to use electronics to give me more options. Looking forward to seeing the experiment.
My controls are so damn hard to reach... I find myself often reaching through the wheel, which is never a good idea. I can't wait to have the new throttle setup!
Ideally we want to measure the internal resistance of each cell that goes into creating a battery bank in series. You want them to be roughly very similar. If there is a mismatch, you may start off with all cells top-balanced, but as you charge the battery system, the cells with higher internal resistance will dissapate more of that power in heat and not as charge. The power loss is designated by P=I^2 x R, the current flowing thru is the same for all cells, but R is the internal resistance of each cell. Hence the power loss in heat produced by each cell will differ slightly based on their internal resistance. And for this reason, the State-Of-Charge (SOC) will drift out of balance overtime if you have a battery pack with a high mismatch of cell internal resistance. So what you have mentioned having a BMS is absolutely correct, either passive balancing or active balancing, this functionality will be required to maintain a good health for the LFP battery pack. If the SOC of the cells are not the same, as the battery gets charged, the cell that reaches full charged can no longer take on more charge. The only way is to dissapate the energy as heat and it will heat up a lot more than the others that can still take on charge. OVertime, this will significantly reduce the lifespan of the battery pack.
They were all matched at the factory when I ordered them. Of course, the IR changes with the SoC, so IR matching is only so good in the end, but agreed, do your best.
I have watched several of your videos and like the content so far. I also am a huge fan of Andy and the Off-Grid Garage. I had a thought when watching this video when you stated be out in the water away from shore. I also watch another youtuber that spends much of his time on a sailboat. He has a device called a bank manager. Allows you to mix lead and lithium banks. I understand you have 7 48v lithium banks which is amazing. I also understand you are planning to move to all battery power for propulsion. All that said I like to think through backup plans as I have learned in my life that sometimes "Murphy" is an optimist. Meaning even things that should never go wrong sometimes do. That said I am not sure if a backup generator is an option. not sure if using some sort of alternator or anything of the like as part of the plan. The bank manager that Clark has developed is of interest to me. I am planning to get a bank manager and try it out with Lead and Lithium on an RV. He also has some videos on a DC powered Air Conditioner. these may or may not be of interest but thought I would see if you are aware of Emily & Clark's Adventure th-cam.com/video/sqT27KbxRec/w-d-xo.html .
Loving the white fluffy snow, unfortunately where I am we got the mostly water snow. So the plow row was not so much fun. Anyway, KW looking fantastic.
It's really pretty here! That big branch that came down was from the wet kind of snow... We had a good bit of snow, then it warmed up and turned to rain. The snow got super heavy and broke the branch before it melted. Ah well, such is life in Canada
Grew up in KW, we got some real snow back in the 70's. I had my first thundersnow experience there, although no one believed me. Still, I'll take a good healthy snow over the constant threat of ice rain we have now.
@@mickey4947 Oh nice! I moved to KW a little over a decade ago, never expected to stay here this long, but it's not a bad town at all.
Question: Do you plan to keep the boat on the hard until the conversion is done (or ready for testing)? If so, your broker could negotiate a policy that protects your boat on land while you work on it, with the understanding that you'll renegotiate for a policy that would start when you hit water. Maybe they wouldn't mind insuring a boat that is just being worked on. And that buys you some time, and you'll have something to show for all your work, which could convince the insurance company that your new electric boat is insurable.
Partly, yes, and I asked about that. He was saying that they might worry about things like welding or whatnot (why they don't want to cover during the conversion work). I explained that I had no plans to do welding in the boat, and that I am well aware of the risks of things like oily rags spontaneous combusting and would take appropriate measures. I also said that I am happy to agree to not do certain work on the boat if that would allay the concerns of the underwriter. He's taken all that back and he's doing his thing now.
The current goal is to get the motor in and the new wiring done and signed off ASAP. The boat will NOT be done when I go in the water, not even close. Heck, there's a good chance the old rod rigging will go up for one more season. The goal is to splash and start sea-trials as soon as I can.
Hi, Still was thinking about a comment about your head scratching problem of the last video...and you put up an other one... your fast:))
About your fastness but concerning the pre resistor thingy there a simple solution might be to look at a different kind of switch. Or better two switches with removable keys. But using only one key for both switches. One switch is just for the loading through a resistor to load the capacitor. when that is done, switch it off, take out the key and use it for the main switch. This way you build in the seconds you need. And after a disconnect is needed, and put the key back in the preload switch.
The setup of 1 key for more battery switches which dictates the use, connections and possible problems is also handy for more battery boat related switching stuff, Like preventing flyback on alternator switch off, combining, separating or directing banks/power to certain equipment, like in an emergency use.
As for insurance, i would like to know what the Electrical Boat Associations of America en Canada, as well as the Sail Canada body as the Office of the Superintendent of Financial Institutions (OSFI) has to say about that. Because if insurance companies make fossil to electric conversions, in a time of climate change and energy transition (think big here) practically impossible for boat owners this is and will be a big issue.
The key idea is neat, but I can't ignore complexity... what if I can't find the key? I think the cover over the switch is, for my use, the best combination of simple and reliable. Adding a buzzer as others suggested might be a nice addition, have it buzz when the lid is lifted, and stop buzzing when the desired voltage is reached would be a great reminder to wait a minute.
On insurance, as mentioned, I think insurance companies are starting to understand that electric is the future, and they have to get onboard. Marine / sailing _everything_ is slow and resistant to change. I'm hardly the first conversion, but it's still pretty rare these days. That's going to change though.
@@TheDigitalMermaid There, you made made me smile again:)) Complexity is just for those that do not (yet) know how. Like a mason will find a solution in brick, the carpenter in wood to solve the same problem. Well, and since i am a more creative guy, i would suggest or make myself, to solve the "what if I can't find the key?" question with: make a bit deeper frame with glass of 15 x 15 cm, (like the fire alarm buttons boxes) hang as much keys in there as will fit, paint it in any color you want, and hang it in reach on a bulkhead. No power needed, well protected in heavy seas and always usable. :) And regardless, those "what if" questions you ask are always good questions to ask specially in risk management.
As for insurance. I did make some calls here in the EU, and 90% of them state that, any conversion to anything is allowed and insured while work is done under the old policy, and when finished the result is checked and signed (and payed for by user) by a certified company and will result in a new policy contract. Sadly none of them will insure owners outside the country or EU. The one that do, are Pantaenius.com, headoffice in UK. sponsor of sailor Skip Novak (se here on YT) or the marketplace Loyds.
@@LucScheffers Seems like these insurance hassles are pretty specific to Canada. Lucky me. :P
Well, you mentioned safety. On that note, when you do get back to battery building, please drill your attaching hardware and lockwire it. We use it in aviation (my industry) and i also see it a lot in motor racing. Key point - constant movement, flexing, continual impacts will end up with things coming off (im thinking slapping against waves for days and days... those forces add up). Big current involved with those banks now equals potential arcing and fire with loose battery connections. Last thing you want (ironically) when at sea while surrounded by only water. Once you have drilled the hardware, practice putting it on so when the nut tries to unscrew - it tensions the lockwire and cant come off. Have seen too many lockwired back to front and it will get loose. Anyway, future consideration.
Its a pain sometimes to do... but we use it in aviation. All our rules arent just written in blood, its graves (many unmarked). As you say, you cant just pull over and get help.
Take this advice as you please.
And bonus credit for Kepler. He had much valuable contributions :)
Oh if I could somehow reliably drill a hole in the battery posts so that I could get seizing wire in, I totally would! The concern for movement is why I put so much time into coming up with the flexible bus bars... I may splurge for the final build and get nordlock washers and fresh posilock nuts, as the next best thing. Periodic thermal checks with the FLIR will be part of my maintenance routine, also.
@@TheDigitalMermaid for the amount of money you could spend on posilock nuts and the like, I have no doubt you could engage the services of a local engineering firm / machining shop for an hour or two who could expertly drill the posts for you. Would just require hauling them there and back in batches perhaps?
I'll get through the first season / sea trials, and see if anything shows signs of moving (witness marks). If anything does, then I might just do that. The idea of machining so near the cells of the batteries makes me nervous, so I'd want to know the effort, risk and cost was worth it. If I don't, annual maintenance will be checking all nuts.
Nice a TALK show.
Aye, I admit I kinda phoned it in, but as I mentioned the dayjob has me super busy. I've got the helm video half done, so the next one will be more doing and less talking.
Hi Im new here. Looking forward to the upcoming venture. Uncommanded vehicle movement claims.....
I've always have inexpensive test lights in my kit. The inexpensive ones just have a an incandescent bulb rated at system voltage. So, they are generally rated at 12, 24,48 and so on and are relatively low wattag. I find them useful because the brightness intensity indicates both current and voltage which speeds testing along multiple contacts. Since they're always available at hand I've never used a pre charge resistor. By using the test light instead, I can see the light intensity come on then off to dark which is a positive indication that the charge happened timely and completely.
I had an 18 volt LiFePo4 battery pack EXPLODE recently. It had been reliable for ( 8-12 yrs maybe?), hundreds of hot and cold cycles to dead. Anyway it finally let go. It had been out in the cold probably partially charged and with winter coming on strong I had decided to stick in the chargeer mounted on a timber post in the shed. The charger didn't indicate undertemp but instead went to charging the pack. It was some time later, maybe 6-12 minutes that I got shocked by the sound; it was a loud sharp crack like a small cap in a toy followed by a loud his for nearly a second. I was shocked, sorta like when the electrical arc happens; it kinda stunts you for a split second but it's very real. My mind flowed full of concerns regarding fire as my eye spotted a gray plume erupting from the pack like steam. The explosion plume engulfed an area greater than a postage stamp and the cloud arose up nearly a finger length. My decision was to immediately disconnect the charger plug ftom the supply outlet. That really calmed me down snd I listened closely for what I think could've been a sizzling. It wasn't really sizzling I thought, so I touched it and it was cool. That pack is still sitting right there on the bench. Anyway, I popped in the next pack and got a low temp indicator. I warmed the charger, pack, and remaining packs then charged them fully without any problems. Looking at the exploded pack there was no external damage and no signatures of heat, so probably just one cell ruptured. It would be interesting do do some more destructive cell testing and predetermine the best enclosure, venting, and serviceability. 👶🏻🚬
I think in the spirit of experimental transportation one should protect others with liability insurance, self with health care, and asset protection by not experimenting. Probably divide the assets and coverage limits/types.
What will one of these cells do at 48 volts?
The light idea is something I was leaning towards, but someone else suggested a buzzer the goes off when the desired voltage is reached, and I really like that idea, so that's probably what I'll do.
At the end of the day, anything that stores any kind of energy sufficient to move a vessel comes with some danger, same is true for diesel, gas, lead acid, etc. As with all tools, care has to be used to use them safely.
@@TheDigitalMermaid Yes, I agree. I suspect that the LFP venting system is adequate outside of an enclosure. Probably the flame front is mostly self extinguishing so unless high pressure fuel is spraying on it there is just the matter of direction of pressure away from structure and person. The hall sensors of esc motors should be sufficient to limit most un-commanded movement in most boating applications. Generally, I think sometimes technology can be unnerving when we are surprised by an unforeseen fault which gives way to a deeper appreciation or understanding. I love the fast reliable nature of an electric drive going forward and in reverse.
If you saw the breadboard in the video, there was a little red switch hanging from it. That's an "oh shit" button, when pressed it forces the motor into the neutral position, stopping the motor no matter the throttle position. Later I plan to have (as required by ABYC) an emergency kill switch that will shut down the motors directly by commanding the contactors to open.
Sunny hot Australia, now where have I heard that before? 😎
:D
I have used jbd bmss for four years and have had very minimal bad experiences
If I was pressed into a corner today, that's likely what I'd get, with an external active balancer.
I have a 36" soft bristled horsehair Floor BROOM with an extra long handle
for BROOMING Off any Snow that accumulates on my 30 panels on a 45 degree angle ( PV Panels )
the Final SIX (6) Panels are 180 degrees (vertical )
I do not attempt to "clear" my 700' gravel driveway
COOP
...
on the plus side,you are not totaly stuck waiting on incurens, you have projects you can keep working on. But a bit of a roadblock to be sure. Hoping for the best.
Aye, thankfully there's no end of tasks to work on
While I completely understand your position on JK-BMS it should be noted that they have come out with a new firmware that would prevent overcharging in the default mode. As for the upcoming videos, I'm am fairly certain that most of us watching are nerds of one sort or another and the credo of most of us is that more knowledge is good so try not to worry so much about weather we're going to like it. I know I will...
Thanks, Eric! I'm hoping folks enjoy the short topic change. :)
Being conservative on how you use batteries is good. Sailing is risky enough without adding additional risks into that equation. You are right that a car or house is a different use case.
Yup, exactly. There's no "right answer" for all cases, just right answers for any given case.
The problem with being the very early adopter is that you are a guinea pig. Sometimes it is better to take the second taxi off the rank. Keen to see if Andy the JK guinea pig will end up with the ideal 48v lifepo bms. Better to be a happy second rank adopter than the sometimes first adopter Victron gear looks good but is very expensive.
Trick is that JK isn't really a new player to the BMS space though. Their development methodology is "most features or least money", and clearly it works for them.
Well said about JKBMS on a boat. I don't recommend them on a boat as well even the new ones that are parallel capable. They have not proven themselves in the field.
Aye, it's very much a "what's right for you?" case.
Hi back Mermaid!
Howdy!
@@TheDigitalMermaid I guess I should make a video of an LFP cell like an EVE going to 4.2V - it's not pretty. I'll see if I have time in the lab...
@@upnorthandpersonal oooooooh, please take video if you do!
I look forward to "The Nerdy Bits"(tm). Having built an EV "racecar", I'm curious about your motor and control setup. The HPEVS AC51 we used wants to run at a rather high RPM (for a car). We drove it like a normal car - 2-3k RPM - and it quickly overheats. Spin that puppy up to 5k+ and it'll run all day. (it is based on a low voltage hydraulic pump motor.) Like everyone does, we use a Prius throttle peddle. I don't know if there are any drive-by-wire boat throttles. If you took the spring out, and used a fwd/rev switch, the prius throttle might work.
Air-cooled motor? I'll be interested to see how different the water-cooled performs at different throttle positions.
@@TheDigitalMermaid Yes, air-cooled. They made "marine" oil cooled versions way back, but not for many years.
for the helm /throttle have you looked in to a solid state solution so there are no risk of corrosion. potentially with a magnetic rotary position sensor have had good luck with a AS5600.
Huh, that's interesting... So you rotate a magnet over the IC? The pot I've got is sealed, save for the pins. So I'm pretty comfortable corrosion won't kill it particularly fast (and I'll have a spare), but that is an interesting option. The trick I suppose would be to pot the board, unless I wanted to trade one issue with another. :)
yes just rotate a magnet over the IC. but yes you would need to give the smale bord 25x25mm with the IC a dap of epoxy and then you can communicate with it over i2c and pick between Analog out / PWM / I²C as a output.
but if the pot you already have is sealed you should also be got.
bms is a must AND active cell ballancer is a must, not recalling the brand i used as it is not important and probably not for your battery in your boat as this is in a rv, but when thew battery had down time i.e at night the cells have time to reballance, and the ballancer turns off so it is not a draw on they system when it reaches a ballanced state.
The BMS is a safety device, and so an absolute must imo. An active balancer is fantastic for efficiency, but not having one isn't dangerous, per-se.
I know from experience that you absolutely can run Li-ion batteries being charged in parallel with only conservative pack-voltage cutoffs for years, and it works great. Then they catastrophically fail.
And that's just it... "But it worked for years!" is the common refrain of someone who just suffered a catastrophic failure. Heard it countless times in my past life's work.
mine are 13c or 55.4f
I think that's an entirely reasonable temp. I suspect that I'll turn on the heater in my setup when the engine/battery bay gets into the single digit (c) temps, but I'll need to do experiments to see at what temperature does the extra energy / cost of heating cost makes it worth while.
@@TheDigitalMermaid unless you are going less than 0C 32F I do not see why you would heat them. You might want to cool them in the tropics.
@@dc1544 I very likely will be below freezing, if things go well!
@@TheDigitalMermaid remember your boat is fiberglass not metal so it's skin is fragile. Don't get into dangerous waters
@@dc1544 I won't be going anywhere other plastic boats haven't been before me. :)
You nailed it again! I am really keen on seeing you go through programming the arduino; what language you will be using - I know nothing of arduino's though I have thought of getting one to play around with. You will probably tip me into it - what a channel!!! Tom
Thanks, Tom! Arduino is C++, and it's IDE makes it really easy to get into, as it masks all the firmware flashing and whatnot that can make it hard for new users. Cheers!
I respect the JK update here. Have you looked at the REC BMS?
I do not miss the snow from back home haha. We have an M3LR, in a warm climate. How do you like it where you are? Just keep it topped up so you can keep the cabin warm? What year? I hope newer so you have a heat pump heater and not a resister :D
REC is good, but I would like a more modern option with active balancing. I've got time to sort that out though. For now, the JKs I have will do.
I've had no issues with the MYLR, the range loss in winter is easy to offset by just slowing down some, though honestly that doesn't even cross my mind unless I'm driving for a few hours at least. I think mine does have the heat pump, and I'm even toyed with the idea of buying a spare one for use on the boat... :D
There is a bigger problem with systems that communicate and are controlled by the bms. This was a big part of the problem with the wrong bms settings. So if charger/ mppt solar are controlled by the bms they can very easily overcharge. See victron DVCC. Heat in the wires is counted in the result because the current is the same in the loop (current doesn't run away).
I come from a Linux (unix) background, and I've really come to love the design where each piece worries only about the piece below it and above it, nothing else. Trying to have a master systems that tries to understand and control everything is ... complicated.
For insurance, have you checked Edward Williams? I did successfully claim from them before, but due diligence is definitely needed.
They're my insurance of last resort... I know they're really hard to make a claim with, and some marina's won't let you in if that's who you have for insurance.
I cannot believe that you (we) are still debating the BMS requirement thing. Please simply do not acknowledge the comments and focus on what is really important. Keep up the good work!
those red battery disconnectors what are they rated for? It took me a bit to find ones that are rated for 60V. Contact Blue Sea systems and see if the ones you have have been tested for 60V( over 48V).
They're rated for 300A continuous, 500A peak at 48vDC, as you saw. In my experience, everything marine that's "rated for 48v" are good up to 60v, as the "48v" is more of a class rating. I suppose it wouldn't hurt to confirm, but I'm sure it's OK.
Look at Rec BMS, Has precharge circuits. Can run multiple BMS , master slave configuration.
Aye, I've looked at them. They're good quality, no question, but somewhat lacking in features. In any case, it's on the table for sure.
They did have a new model Rec 2 Series 16s BMS come out last March.
@@TheDigitalMermaid
HOWdy T-D-M, ...
cold - Cold - COLD outside !
"0" F degrees = ( --18 C degrees )
but
sun - Sun - SUNNY too =
my BATTERIES are ALL @ 100% SOC at 12:00pm NOON 🙂
Thanks for POSTING
COOP
the WiSeNhEiMeR from (frigid) Richmond, INDIANA, USA
...
Aye, she's a cold one today...
SNOW Shoveling = I need the brand NAME & Strength of you COFFEE !!! - LOL
COOP
...
You'd be disappointed, I fear... I drink instant coffee... haha.
YIKES = I figured YOU for a:
French PRESS " Woman ! LOL
COOP
...
@@TheDigitalMermaid
pretty ok news about capacity .. just let that pack get older and feel ok with its rate of degredation !!! you have the privilege to get older in so much lower rates and you are going to try even more new energy storage chemistries!!!
Aye, I knew when I bought the cells early that I would lose some life in the batteries, and watch the prices come down. Oh well, I've learned so much in the time in between that it's still worth it.
It snows in Australia..........in a few months' time.
Aye, but not in "sunny, hot" Australia :)
@@TheDigitalMermaid Depends on where you are :-) don't trust Andy, he's biased.
@@itstackyandtawdrytime Haha!
Hey don't forget Andy got jo to put out a firmware update of course if this is an older blog maybe you have found out
I think I mentioned the updated firmware, by version actually. My concerns remain, not because of this one bug, but because of multiple issues I've had with them.
Going too low on LiFePO4 is not as harmful as going to high, you do not want to go over 3.65 or worst case 3.8 but that is causing damage. I accidentally went over 4.0 on two 200Ahr cells and they puffed up badly, tho still work they are only 80% now and probably won't last so i don't use them now. They are so puffy they won't fit nicely in the case.
So over voltage has no room for error, under voltage from 2.0-3.0 will not hurt them as you know, below 2.0 might not be good either. Same goes for other types too. Over charging is damaging of the cathode and causes gassing for all types of cathodes, they have no tolerance for excursions on the high side.
Huh, good to know about the over-voltage. Another person here said they're going to see if they can test over-charging a cell to see what happens and at what voltage.
You know there are electric(battery) snow blowers?
I do, and I almost bought one. My lawn mower is electric, too. The reason I didn't bother with the snow blower is that I know I'm leaving soon to live on the boat, so it was hard to justify the expense.
here it is also SH*** F*** COLD X-D
Haha! Life in the north...
Why don't you acquire prebuilt EV pack batteries that are essentially weather sealed? I'm purchasing 3 packs, each 35kwh sealed and epoxied together. I can just drill a few holes and run the wires outside and then seal the holes up to prevent water from getting in. T hey have a strong casing and the base of the case is a rrigid metal platform, they will survive marine movement.
Two major reasons, and a two important reason; 1. Most EVs use NMC cells, which combust on thermal runaway. LFP cells don't, but exceedingly few EVs in north america use them yet. 2. EVs need much higher power motors, and so they run at much higher voltages (200, 400 and even 800v). Using high voltage on a boat is a lot harder given ABYC requirements, so staying under 60vDC makes things safer and easier to meet regulations. 3. I Need to know that I can repair the system myself. EVs have closed controllers so if they fault, I can't do anything to reprogram/fix them. Same for the batteries. 4. There is virtually zero EV charge points in marinas, so one of the biggest advantages of an EV pack, high speed DC charging, wouldn't be available to me anyway.
Hi Maddy, have you come across REC-BMS?
Very popular high quality external BMS over here in Europe. They have 48V models so you could build a monster 6p16s pack. Certainly no pre-charge issues with that! Talks Victron CANBUS so fully compatible with your Cerbo, Multiplus and MPPTs. Charge controlled over CANBUS but also has several configurable relay contacts to force charger and load cutoffs based on cell rather than battery voltage. Very well engineered BMS.
Thanks for sharing your project. All very interesting 🙂
I have, and from what I understand, they're very good quality. I wish they had an active balancer and bluetooth, but so it goes. In my case, I really want to have the seven batteries each self-contained, so that a fault in any one only takes out 1/7th my total capacity.
Maddy,
Just wondering what you main reasons the JK BMS you help up is in the not recommended list?
Until last week’s fiasco my one JK BMS was the only bright spot…
In general BMS are a bit of a horror show: Weak or un-useable balancers, inaccurate SOC integrators, unable to easily reset battery to full SOC, initial startup process after complete shutdown, etc. Daly, JK and Jiabada (and derivatives/clones/relabels, I tried them all)
I looked at the Victron, but the complexity for a simple system appears too high. If Victron made a simple BMS with working balancer I would be the first in line. Their coms/Bluetooth implementation is stellar. Work of art.
To me, my JK at least is the only BMS that can actually balance a battery that needs it. I’ll live with the other items. On the others I need external balancers and they introduce their own issues…..
I realize the issue last week was a release test failure and it seems to have snuck through. It should not, and hopefully they fixed it. I put this on the catastrophic bug list…. But does it apply to the BMS you showed?
Anyhow, I would appreciate your understanding of why you dislike your JKs? I could re-watch the videos, but I do not remember any problem you had that I did not see with the other BMS’s I used….. Thanks. Just wondering.
I had long been frustrated by JK, with their willingness to change features / capabilities without changing the model number being a big part of that. I could review a BMS and decide it's great, then viewers could order the same part number, and get a different BMS. That makes it almost impossible to recommend it. The most recent issue just underscored how little they care about safety, a separate and very bad problem. If you have a JK BMS and you're happy with it, great, but for me, in my use case, I don't know what other ways this thing could fail. I just lost my trust in it. In a sailboat, out in the ocean, I must be able to trust my safety equipment.
A fellow sailor i know, who uses a 16s LiFePo bank to power his me1616 told me he never had a bms. I asked why and he said the peak current sometimes is to high and his bank is almost never fully charged so the bms does not balance anyway. He checks his cell's on a regulair basis and top balance them every half year or so. He has been doing that for years with no problem and is all over the globe.
His batterybank is also used as housebank, charged by a generator and pv's. I don't think it's smart so i am using a jk 200A bms in my build. Now i hear this is not absolutely safe also. What BMS is???
In the end, there is no perfectly safe solution. This is why I was careful to say in this video that I am talking from my point of view, and from my personal feelings of what is acceptable. While I disagree with your friend that "I don't need a BMS", disagreeing is not saying he's wrong, just that we've come to different conclusions.
Hello sorry its me.
On the subject of a cavalier attitude to safty, have you a back up propulsion engine or do I understand it correctly you are going out to sea full electric?
I will, actually. I spoke about it in a previous video, I'm planning to have a 10kw and a 5kw motor, each with their own dedicated controller and cooling loop. After breaking down three times because of failures with the diesel, I want as much redundancy as I can afford (cost, space and weight). And yes, full electric.
@@TheDigitalMermaid Do you have sail to fall back on?
With a 10kw motor even at half speed you ain't got that much endurance at all.
@@garys-half-baked-offgrid-dream Yes, she's a sailboat first, these are auxilliary motors. That said, one of the key design goals for me was to develop an electric system that would let me run mast-down in canals, and I think I can do it. As I explained in the "Decisions Made" video, using a similar boat that was converted to electric using a similar motor, I think I can push at 4 kts in flat-calm conditions at ~2200watts, or at 3kts at 900watts if I really wanted to maximize range. With my usable 96.3kwh of battery, that translates to 43.7 hours at 4 kts (175 nautical miles), or 107 hours at 3 kts (320 nautical miles). I'll be able to recharge at just over 4kw on shore power, so I can recharge at ~2x ~4x faster than my consumption rate, giving me a solid two days of travel per night of charge, at 4 kts.
@@TheDigitalMermaid Like planning a PV system summer is easy winter is the acid test. Plan for broken rigging, heavy sea's with a head wind and the rest will be gravy.
I know we got off on the wrong foot, I genuinly mean you no harm and wish you all the best with this venture you're braver than I. I watched Jaws at too young an age. Inland water I am fine out at sea my bum squeeks.
Out of curiosity what's your plan on how to test your theoretical range saftly?
@@garys-half-baked-offgrid-dream That's why I am so focused on charging from regen off the prop... The solar generation is going to be bonus watts, basically. I want to sail to high latitudes and there, even on a clear day, generation is limited. That said, I'm hoping to get ~1000~1500w of solar. Part of why I chose the Landfall 38 is because the main boom ends a good 2 meters forward of the transom, so pleanty of space for a generous solar arch.
The plan to range test will be to disconnect one battery and run the others from max charge to dead empty vaguely around the area of my marina, then connect the spare pack and use that to get back into port. Fairly easy math after that the figure out how far I could have gone on all seven. I'm also curious to see how the regen works on the 10kw vs 5kw, and at different speeds over water, to create a somewhat accurate graph or the real world regen.
And no hard feelings on my end. I have my opinions, I speak those opinions, and don't mind at all if people see things different. All good on my end. :)
The problem with JK BMS’s is not with what you using, that’s is a different model
This is why I made the point to clarify that "are JK good?" is a question each person has to decide for themselves.
You should have totally started this video with Andy’s intro music 😂
Heh, I debated it, but decided that would have been too much. :)
Next time 😂
Hi
Since you have multiple battery banks, should consider adding some redundancy to your system to prevent single point failures.
Each battery has its own circuit breaker, eBay has lots of AIRPAX LEL
Use multiple MMPT for your solar panels.
Oversize high current wires.
Use multiple DC/AC inverters, also reduces parasite load since you can turn of circuits Victron Inverter VE.Direct 250 to 1200VA
If you are really keen multiple DC busses.
For a salty environment use electrical grease on all your high current connections.
Make sure all your high current connections are easy to inspect and fix.
List of spares and tools.
Multiple smoke detectors and electrical fire extinguishers.
If you check the older videos, you'll see I'm quite the fan of redundancy and oversizing things. :)
The only chemistry on which you do not need a BMS would be LA or AGM, but they carry their own pitfalls.... Anything Lithium, you need a BMS, you might not need the Inverter to know what is going in the BMS eco system other than voltage but, you need a BMS....... If you use lithium and you have no BMS...... You are most certainly looking for trouble. The pre-charge.... Use a micro switch or micro leaf switch on your lid, when you lift it, the switch can close it's contacts, engaging the pre-charge resistor....... But, your choice.
Aye, BMS is a must in my opinion. I just don't want to be that person that tells others they're wrong. Up to each person to decide what's right for them.
Having no BMS is killing, there is footage of a German Garage which was on fire because of this. Never do this, as you correctly point out.
It's a level of risk that's not even in the same ballpark as my risk tolerance would allow.
That loose end about BMSs and that cell that gave trouble.
Don't feel at all guilty about letting loose about JK because, in a number of ways, they deserve it. I just cannot fathom "oh we can easily put out a firmware update" as being an acceptable approach to quality management - just what happened to proper testing? Beyond that, I don't recall you telling anyone what to do with JK BMSs, only what you were inclined to do.
About that dodgy cell. Was that not caused by the battery being left for ages - with the BMS still active? Would you actually do that if you lived aboard your boat? My guess is that you'd be watching batteries like a hawk. Even then, the worse thing a dodgy cell can do is to cause that battery to switch itself off - but don't you have redundancy built into your design? "Lose one" need not mean "lose all". I wonder too, if there's a case to be made to sail with a maintained spare cell, "just in case"? Maybe that means DIYers clubbing together to buy four and sharing them around. After seeing Andy build his "Frankenstein Battery", switching out a dodgy cell might be quite doable.
Heh, I didn't think I did, but some people got upset like I personally insulted them. Oh well, I clarified my position and if someone is still upset at me, so be it.
Ya, I was running a (now aborted) parasitic drain test. It's still odd that the one cell fell so low while all the others (95 others!) were still happily at 3.1v. It was odd. In the end, this is also why I am building seven independent packs; Any one failure will only take out 1/7th my total capacity.
The thoughts you brought up about the JK BMS are valid in with your context. Your use case has a life-or-death aspect to it and the suppliers of critical components of your system should at the very least be honest and consistent about their products so that you can feel comfortable that your technical decisions will hold up if the proverbial shit hits the fan (and if you're anything like me, the shit ALWAYS hits the fan).
Unfortunately, following your train of thought, you should stay from all Chinese products in general cuz I've come to realize its a cultural thing; there's something about the current Chinese culture that makes them dishonest when backed into a corner and combined with their atrocious English skills and their inability the admit wrong doing, continued use of their products requires a hope-for-the-best attitude and a read-between-the-lines discernment when judging the veracity of their not so good English.
But where does that leave you? Aren't your batteries China made too? I tell you, the times that we live in are NOT easy.
There's some fantastic kit out of China, look at BYD for example. I think we in the west mainly see the cheap shit because, well, that's why we go there, looking for the cheap stuff. There's of course a big cultural difference, I'm not debating that, but I'm not keen to paint any country with such a wide brush. The trick is evaluating any one company on it's own merits and, as you mentioned, for my use JK isn't appropriate.
As yes, the quagmire of insurance... with a high power electrical mess you made yourself. I can see them all running screaming from the room. :-) They're worried your DIY setup could kill people, burn down a dock, etc. People legitimately have loads of concerns about safety. Even more so when it's something you built yourself. Factory made, factory tested that have someone to sue are a different matter. (still an uphill road, 'tho) If you can show them proven safety technology -- BMS, physical disconnects, fire suppression, fire limiting battery box(es), fuses, etc. (and a plan to deal with a fire) -- they may be more receptive.
It'll be interesting to see how this goes. I'm sorry you have to be the pioneer here.
In the end, it comes down to getting an ABYC certified electrician to inspect my work. If that passes, I should be good.
I wonder if anyone's charged to 7volts to see what happens
I saw a video going around where someone charged an LFP to 15v and it legit popped and caught fire. It wasn't a lab test, so who knows what actually caused it to go, but it wasn't pretty.
@TheDigitalMermaid I bet it wasn't good I've seen a picture off a ecoworthy battery in a really bad state split the battery in two nearly I would show u but can't on here they are pouch cells too lifepo4 was easily 3 times the size
@@davidhopkins9021 I've seen 8s LFP prismatic cells using rigid bus bars turn into bananas after being overcharged. They have an extremely low chance of catching fire, but the force they exert when swelling is pretty impressive/scary.
@@TheDigitalMermaid yeah I bet it is amazing really and scary like you say and another great video
insurance can say no, just wait until electric cars are non insurable, coming soon.
Um, what makes you think electric cars won't be insurable!?
@@TheDigitalMermaid
There are already a few that state that you can’t park your electric vehicle in your garage. Ignorance on the insurance company’s part.
@@SkypowerwithKarl Wow, seriously?! I suppose, given how gas cars never catch fire, it's understandable... /s
@@TheDigitalMermaid
I totally agree with you. But companies don’t hire people based on intelligence and looking at facts.