I took the diesel out of my Gozzard 31 and put in an Electric Yacht motor with 48v 200ah LiFePO4 (4 50a batteries). Also have a 12v LiFePO4 as the house battery, which can be switched to receiving charge from solar or the engine bank via a 48-12v converter. I went all Renogy components to have a one-stop support desk with the supplier. For getting in and out of harbors/anchorages this has been fine so far. Exploring augmenting with a 3.5kw Ecoflow rather than adding more engine battery. Thx for the great videos.
Thanks - will use this guide for sure. I also like to know that everything is assembled with lots of TLC. Looking to build a 40kWh+ @ 96v to run my new outboard motor and get rid of the stinky combustion motor.
To answer your question I have 560 ah 12v in my Catalina 30 made from 280ah cells. With 300 watts of solar and a igen 2600 genset everything works pretty well. No electric propulsion. In my RV Overlander conversion(Former Isuzu NPR) I have 1120 ah in two 4s2p batteries. The truck has 2160 watts of solar and an ev charging plug in the side. Also a mini split. I am bringing it to the Annapolis boat show if you wanted to see the rig, and hopefully I can find safe parking. That is going to be a problem, but it is pretty stealth if I park it the right way.
I still haven't yet started my lithium battery project but I mostly decided to get lipo 48V 100AH x 4 = 48V 400AH from one of the reasonably priced lipo manufacturers. Currently listed as $1,300 each. Or, maybe I will get more of them, like 5 instead of 4, because they should probably all be installed from a set at the same date of manufacture. I built a vanlife vehicle and am using a lipo 48V 100AH battery in it successfully (I suppose it is rated as 96AH or something but I will call it 100AH), and a victron inverter designed for 48V input, and a solar mppt designed for 48V output. I can use electric cooking appliances in it quite easily (800W for 10-15 mins), run fullsize iMac computer all day (150W), charge Mac laptop (65W), charge usb devices (10W), etc. The biggest build problem has been finding the connection components which are rated for that high DCV. Fuses are typically not rated for the 60VDC which the system needs as a minimum because lipo charging will hit 58VDC max. I have no battery switch (i.e. kill switch) because I can't find one which is rated at 60VDC. I ended up having to use a massive T-class fuse which I forget the details but might be rated for 100VDC. Blue Sea Systems does not make any buss panels which are suitable for 48VDC system, the highest rating they have is 36VDC. These limitations are not obvious from any of the packaging, and the packaging or item listings can even be misleading, so the fine print in their data sheets needs to be verified very carefully. At 25:00 you show a battery terminal fuse, these are not rated for 48VDC, they are only okay for 12VDC, sometimes special ones at 36VDC.
Nice build buddy! I might do one of those myself. I've had a "drop-in" LiFePo4 since the beginning of 2021 which has worked great but is only 216Ah. The cells I have for my electric propulsion are 280Ah so if I used those and built a battery like yours I'd have 560Ah which sounds good to me! Plus they are way cheaper now than they were three years ago.
im afraid to tell you what i did, and now im scared to leave it ! i made five lifepo4 cylinder cell bats,12V 4s15p, 81 A each. i top balanced each 15p group and then balanced each 4s15p ' battery ' i hooked them up to a common bus that is switched to the electrical panel bus no fuse or circuit breaker. i guess i should put in a bms on each 4s15p bat, and a house bank 400 amp circuit breaker !? even though each boat circuit has its own breaker. solar panels through solar panel controllers charge direct to battery bus . i was very happy, although no huge loads have happened yet, with the incredible charge acceptance, but now im scared! thx herb, what a great video ! i also realize i completely misunderstood the function of bms.. i guess im sitting on a 400A bomb..
We have a 400ah LiFePo system I built a year ago which drives a 3000watt inverter for the induction cook top. The 400ah is enough for two maybe three days. The issue isn't capacity, its generation. I'm planning for a kilowatt solar array this winter so we dont run the generator as much. Also have a 140amp alternator but I hate running engines at anchor. Planning a Bahama trip 2025!
@@RiggingDoctor We have 300watts now but they don't keep up. Hoping twin 450 bifacials do the trick. When I made my battery, I bought 1"x.125" copper barstock for the bus bars. 2P4s with no overlapping bus bars. Check out DIY nickel plating. really comes in handy.
That is a very good idea! What I really need to do is get it sizes again so that it can come off, but if I build another battery between then and now, I’ll do that trick with the tape.
I really, really enjoyed this series and past it along to a new sailor, brand new! Will explain later. My boat is on the hard right now with zero batteries. Redoing all the electrical lines, their a mess. So when it's time for batteries, you'll be the 1st to know.
800Ah 24V house bank charged by 5kW alternator/ 1.2kW solar (soon-work in progress)/ shorepower. The bank is for house loads and to charge the starter and windlass batteries. We only cruise the bay (for now) and the large need(want) is aircon and convenience. Concerns for you: AIC rating of MRBF is only 10kA. Safety standards specify class T (20kA AIC) fuse. Also, the different lengths of the negative B- will have different resistance therefore heating. Likely just a bit under normal loads but at high loads it may be noticeable. Not sure why you wouldn’t use a single cable other than space/turns. Again, safety standards would have both parallel conductors capable of carrying the full load. I’d consider mesh sheathing where you have concerns about short circuiting. Not really mentioned but the batt cases will need to be “installed” so they cannot move if on a boat. Pretty great demo of building a battery. There are lots of ways to skin the cat. I’m a bigger fan of an external BMS with communicating (CAN) charge/load control. Serial (in the B-) BMS solutions seem to be getting better and CAN capabilities on these can be sourced now. I would think for your propulsion needs, this could be a huge (more automated, less carbon based) monitoring/control system. $.02😇. (Thousands of ways to do it)
I've had some marginally serious issues out of my JBD BMS modules. They don't balance too well. Also you have to turn balance while charging off or they basically don't balance long enough. Essentially the BMS balances with a paltry 50ma bleed off only. So it only pulls energy out of too full cells and doesn't put it into low ones. I have built new batteries with the JK BMS and it has an active balancer. I have not had problems with those batteries.
Good to know! The BMS from Overkill is the XiaoXiang BMS and has been reliable. The balancing is ridiculously slow though so it’s important to top balance first. The JK BMS does a good job of balancing for you?
@@RiggingDoctor Yes the JK BMS is a miracle worker. I have the JBD(XiaoXiang) BMS in my boat and my electric motorcycle.(Fly E motorcycle) The JBD has caused me a lot of headaches. My motorcycle has gone dead with 25% remaining because one of the cells reaches the low voltage cutoff and all the rest are terrific. The boat batteries always have a large deviation in voltages on the low cells. The JK BMS with the 2amp balancing current makes my cells in the overlander pretty close to perfect all the time except after pulling a lot of amps for a really long time. Even then it is usually like 0.015! If you make more batteries, I highly suggest going with the JK BMS series.
The reason I use this BMS is because of the tests Will Prowse conducted. The Daly BMS doesn’t actually have a functional low temperature disconnect. He put the probe in ice water and it kept right on discharging after surpassing the low temperature threshold. It out performed the XiaoXiang BMS in every other aspect, but the XiaoxiangBMS has better safety control of the cells which is why I chose them for the boat battery builds. As a result of this choice, balancing becomes super critical since the BMS won’t do it for you.
@@RiggingDoctor The Daly really is pretty basic. Watch this video about your BMS the Overkill Solar/XiaoXiang/JBD. This setting change is SUPER important. ruclips.net/video/XI-8MxSgHOA/видео.html otherwise it is the off-grid garage and these keywords;Why 'Charge Balance' is a bad idea and how to auto top-balance a battery over night with any BMS.
I’ll second the recommendation for the JK. Had 6 12kwh batteries for my house (on land)… The JBD (xiaoxiang) BMS caused all sorts of issues. I swapped all for JK after researching options. Been perfect ever since. Check out off grid garage channel for some awesome reviews off various BMS’s. I’ll be doing a lifepo4 build for my Lagoon 43 and will be using JK’s for sure.
Nice work! I applaud your efforts in this regard! I am a huge DIY fan and have considered doing my own batteries. That being said the cost now has dropped significantly on drop ins. We are prepared for LFP batteries and expect to have around 1200w of solar, ~800ah @12v of LFP. I expect 4, 200ah but could also be 2, 400ah or 3,300ah. We will have all electrical galley but still have diesel propulsion with our 250a electromaax alternator system. We are holding off on the upgrade to LFP until spring of ‘26 when we move from the Great Lakes south to warmer climate! Keep it up!
I have bought 4 * 400 amp @ 3,2v, and still have to choose the BMS. I will maybe add a second set for 200 or 400 amps if I see it necessarily, I choose to be conservative (I use induction for cooking and electric water heater, so I aimed low on purpose to have a functioning system and expand based on 1 year worth of real data or so).
That’s a solid plan. Unless you have an electric motor, it would be hard to exceed the limits of the BMS. If you do find that you are exceeding the capacity of a single BMS, stacking another one in parallel will double your capability.
Get the JK BMS with 2amp active balancing. I have dual 150amp batteries. Trust me the active balancing makes a huge difference especially if cells get low. Most of the BMS's have a resistor that bleeds current from high cells only. 50milla-amps instead of the JK 2000ma. Low cells are left to rot, and that can mean the batteries shut off prematurely. Get the JK and it makes any cell variations virtually disappear.
You do not need a BMS with high amp. I have a set up with 50 amp BMS on 400 amp 12V system. I have my inverter (4000 W) connected to + through a 600 A relay. I let my BMS cut off the relay if I get imbalance more than 0.3 V between my cells.
Did you mention to keep BMS connections on top of the main battery connections? I have read that was important so you don’t run high current through the BMS or other monitoring systems.
I did not mention that but that is a good point. I always build the battery and the last thing I do is connect the BMS. Since they are the last thing on, they are also the top connection.
This is very informative, thank you! Planning to put 16 3,2v 280ah cells in series to get a 14,3kwh battery bank for electric propulsion. Any tips with waterproofing that?
I have built 3 24v batteries (one in the dinghy for it’s motor and two in series for our boats motor) in pelican cases using this same method. I’m going to be building a much bigger battery bank for the sailboat soon and the pelican cases were going to cost more than $1000 so I’m contemplating other options. My current thought is to make a box in plywood and epoxy it to make it waterproof with a clear lexan lid bolted down and bedded with butyl tape. The power would exit the box via the same through bolt terminals. This is my current mental version and it has already gone through a few versions to get to this point. I will be building the batteries this winter for the boat so if you can wait a few months, you can see my final version in the videos and learn from any design mistakes I encountered in the process :)
Thanks for the reply! I was also going for the plywood/epoxy option in my head. This offers some flexibility in the shape of the box all although the cells still need to be (neatly) connected and accessible. The clear lid is a nice added feature, thanks. Looking forward to that video :) might be building mine in the same period of time, then we can compare :)
Please forgive my ignorance, but how is this better/cheaper than just buying an off the shelf 200ah 12v LiPo4 battery for under $600. Is it the waterproofness, quality, size? Thanks for all your videos. I love your teaching style, btw.
It’s the parts that are used. There are many cheaper options, and one cruiser I know had the cheap Amazon LiFePO4 batteries (amzn.to/3sUO5KZ) and it burst into flames. Miraculously, he was able to disconnect and dispose of the battery while it was on fire and while he was sailing without any damage to his boat or himself! This battery is built from the top of the line components using the safest BMS and the best cells. As a result, the parts alone were $1200. Pretty much, you get what you pay for and when you build it yourself, you can select the best parts and save on the labor costs of the build by putting it together yourself. When you consider a BattleBorn battery is about $1000 per 100ah and isn’t waterproof, this battery comes in at a nice price point for the features you get.
This is the price of a premade quality battery (amzn.to/3EFMY4u) and they can still have issues arise on them. It’s rare, but I have seen them “singe” first hand. They have good components in them so the BMS shut the battery down before anything happened. The burnt cell wasn’t discovered until tear down. Cost wise, to get 200ah in those batteries would be just shy of $2000 where if you build it yourself, you can make a waterproof one for $1200. That’s where the cost savings come into play.
What are the cost savings going this route? 20-30% after you "amortize" the needed tools, etc? There has to be some decent gain for you to be going this route over purchasing pre-made and equally waterproof batteries. Apologies if this was answered elsewhere and great vid all around.
The tools are pretty general tools that you should have on a boat, minus the hydraulic press which is very handy if you are making your own battery cables! As for the gains of doing it yourself: you know the quality of the components in the battery and you know that it was setup properly. Yes, a store bought battery comes with a nice warranty, but what good is a warranty when you are in a remote location with a dead battery? By making it yourself you know that it is made right and no cheap parts were used for the sake of improving the profit margin.
Umm, with the extra rubber to compress the battery, does the case still remain water proof? I would think the sides might expand beyond what any gasket might take up. How much does this build weigh? I'm doing an electric dinghy and was using a 100ah AGM which worked fine but I am the only one who can lift it. Climbing into the dinghy while balancing battery on sheer of sail boat and lifting it down is going to lead to disaster sooner or later (though not as bad as trying to lift a 60 pound outboard and then put it on the transom). The 30 pound lifepo4 I am replacing it with can be handed to me by anyone on the boat. It is only 100AH. I would kind of like 200AH for the extra range but 60pounds starts to get back to the I have to do it on my own. I suspect I will end up with two 100ah batteries in the end. For house batteries we had 200ah of agm. I found adding the extra 100ah battery we also used for the dinghy gave me a comfortable voltage in the morning before the sun hit the panels, even with some use on that battery before nightfall. Fridge, freezer, computer(s), water pump, lights, fan. Panels are a mish-mash combination (from previous owner) of maybe 300W?
You might get issues with those not flexible busbars. The busbars are at a angle, which decreases contact area...also those busbars are not good and can get very hot with 50A already. The resistance is too high, because of the small contact area on the battery terminals. But I like your DIY battery design.
Ideally two parallel battery systems sized for loads tied to a PICOGLF30KW300V2083P or 👉🏿 Aims Power Off Grid PICOGLF50KW384V240VS , 👈👍 is most practical IMHO. There are a lot of great LFP cells in the 100 - 340 ah capacity but I think the best and most practical is 110-120 VDC x 2. With a higher budget I'd build 2 x 140 VDC+ The lower voltage battery has the advantage of less PV panels on deck, so balancing between deck space and battery cell capacity first then consider higher voltage if space is adequate. Best bang for the buck hands down. I also like the economy Hybrid Inverter Charger 9.6 kW Power Output 15 kW Solar Input with a single 90-300 volt battery.
You should have strapped cells together. Cells expand(puff) on their wide side, not their narrow side, as you stated. The expanding cells will put stress on the cell Terminals because they are linked by rigid busbars. Try again.
It’s due to the amount of amps that can flow. To use one wire it would need to be a thick wire which wouldn’t be as flexible and that would make the next steps difficult. By using a few smaller wires, they remain flexible and easy to position inside the box
@@RiggingDoctor thank you for taking the time to reply!! I watch your stuff often and learn a lot!! Thank you for the invaluable content!! You make a difference!
@SuperDirk1965 that is true, but you also give up the inherent air cooling capabilities and have to provide the compression system as well. In **this** case, the Pelican box theoretically provides enough force, but why consider that at all? This does provide a method for a smaller, denser battery where space is a premium.
@@TJDST4 You can compress them with anything. Mine are compressed with a charger jammed between one cell and the battery compartment. so no loss of space. I don't have a bms either, just don't charge them above 3.4V/cell and they never get discharged too far. It's a 4S system, 12V 500Ah connected to 200W of solar. The battery powers my autopilot, the fridge and the instruments. At night it powers the lights as well and in winter the diesel heater. It's not connected to the engines alternator, the engine has it's own SLA battery.
EVE 105ah LiFePO4 Cells: www.docanpower.com/index.php?route=product/product&product_id=437&tracking=06ORmUMyyrYyEpQ2VkP7mUHWKgx9B9SeQB6gb57tAV7ag91SsfJ5D2FxQRDgTqmm
They are still going strong. This is for a cruiser in the islands. He’s going to run his whole boat on these two batteries. That’s why I’m building them as 12v batteries. His total battery bank is going to be 12v, 440ah!
That’s why it’s broken up into three episodes with an important disclaimer that you should read about how to do it as well. All the information about battery construction is the same level of information covered in “Physics I” which is taught in high school and college. The goal is not to train people how to do it but to show them how it’s done so that they can learn further and master the concepts themselves.
The cells are slowly being fully charged. It’s pretty much a trickle charge to get them to their absolute full charge level, and on a large cell like this, it’s a slow process. If the cell is 100ah and you are charging at 4 amps, you will be a minimum of 25 hours. As you approach full charge though, the cells won’t accept as much power and charging slows down to a crawl. This is when you find it charging at 0.1amps for a few days. It’s important to do this process all the way so that it is done right and then everything works well afterwards, but it is a lengthy process.
@@RiggingDoctor Thank you for the quick reply. I actually just came back to say never mind since you answered the question in the most recent top balancing video. Interesting stuff.
Yep. It’s bedded in and the battery is going to be installed in a dry environment. On dinghy batteries, I put the terminals at the top of the lid. The reason I didn’t do that on this build is the space and size requirements did not allow the size of the hold did not allow for the terminals to be mounted higher.
How do insurance companies feel about home built DIY batteries, their installation, and wiring? My understanding is insurance companies frown on insuring DIY or they will only pay a small percentage of a claim. 🤔
As always, read your policy. There should be a perils section. I am not aware of a policy that excludes this, but maybe there is one out there somewhere. The perils section for the few I reviewed specifically dealt with hurricanes, storage on land, and blue water limitations.
Li Fe Phosphate should be safe and even water extinguishable.🤔 Ive even seen them built into floodable compartments. .. And they use them as firewalls in mixed Li Fe Li Ion packs. Still play safe if in doubt. .. btw its still worth padding out the battery packs against the sort of g forces encountered in going through a heavy sea.. thats acceleration up to 7g according to one German manufacturer. Safer still are the Li Fe Phosphate blade cells.. Bet your happy you dont have to faff about soldering round cells 😉🇬🇧🧙♂️
@SenatorPerry BTW, I've read/heard boat owners who plan to install their own lithium batteries onboard are being advised to seek professional help or risk invalidating their insurance and manufacturer warranties. If an owners’ system was not upgraded and installed by an ABYC certified electrician, claims may be denied entirely. Like you said, read the policies fine print.
They cost about $950 for a 12v100ah battery where the parts to build this 12v200ah battery cost $1200, and it’s waterproof! I would say it’s a significant savings.
Sorry but the pressing is a joke. According to the manufacturer, it should be 300kg per cell. You have 2 cells next to each other, so it should be 600 kg
I took the diesel out of my Gozzard 31 and put in an Electric Yacht motor with 48v 200ah LiFePO4 (4 50a batteries). Also have a 12v LiFePO4 as the house battery, which can be switched to receiving charge from solar or the engine bank via a 48-12v converter. I went all Renogy components to have a one-stop support desk with the supplier. For getting in and out of harbors/anchorages this has been fine so far. Exploring augmenting with a 3.5kw Ecoflow rather than adding more engine battery. Thx for the great videos.
Awesome video, Herby! Excellent instruction and quality content. Thanks! 👍👍👍
Glad you liked it!
Thanks - will use this guide for sure. I also like to know that everything is assembled with lots of TLC. Looking to build a 40kWh+ @ 96v to run my new outboard motor and get rid of the stinky combustion motor.
I have never watched a boating video which included quite so many repetitions of the phrase "burst into flames" 😄
The important part is to make it so that the phrase doesn’t happen 🫠
Yay!, so glad you graduated past the small cells!
The price point has finally equalized!
I can't wait to make one of these. Bomber.
Well done .
Angus
To answer your question I have 560 ah 12v in my Catalina 30 made from 280ah cells. With 300 watts of solar and a igen 2600 genset everything works pretty well. No electric propulsion. In my RV Overlander conversion(Former Isuzu NPR) I have 1120 ah in two 4s2p batteries. The truck has 2160 watts of solar and an ev charging plug in the side. Also a mini split. I am bringing it to the Annapolis boat show if you wanted to see the rig, and hopefully I can find safe parking. That is going to be a problem, but it is pretty stealth if I park it the right way.
That sounds epic! I would love to see it when you come to the show!!
I still haven't yet started my lithium battery project but I mostly decided to get lipo 48V 100AH x 4 = 48V 400AH from one of the reasonably priced lipo manufacturers. Currently listed as $1,300 each. Or, maybe I will get more of them, like 5 instead of 4, because they should probably all be installed from a set at the same date of manufacture.
I built a vanlife vehicle and am using a lipo 48V 100AH battery in it successfully (I suppose it is rated as 96AH or something but I will call it 100AH), and a victron inverter designed for 48V input, and a solar mppt designed for 48V output. I can use electric cooking appliances in it quite easily (800W for 10-15 mins), run fullsize iMac computer all day (150W), charge Mac laptop (65W), charge usb devices (10W), etc.
The biggest build problem has been finding the connection components which are rated for that high DCV. Fuses are typically not rated for the 60VDC which the system needs as a minimum because lipo charging will hit 58VDC max. I have no battery switch (i.e. kill switch) because I can't find one which is rated at 60VDC. I ended up having to use a massive T-class fuse which I forget the details but might be rated for 100VDC. Blue Sea Systems does not make any buss panels which are suitable for 48VDC system, the highest rating they have is 36VDC. These limitations are not obvious from any of the packaging, and the packaging or item listings can even be misleading, so the fine print in their data sheets needs to be verified very carefully. At 25:00 you show a battery terminal fuse, these are not rated for 48VDC, they are only okay for 12VDC, sometimes special ones at 36VDC.
I was not aware of the voltage limit! I will look into this right now!!
Thank goodness, they are rated to 58v amzn.to/3XQqSat
Can't wait to see this phase of Windpuff!
I can’t wait to build it either! I have so many plans that I can’t wait to turn into reality
Nice build buddy! I might do one of those myself. I've had a "drop-in" LiFePo4 since the beginning of 2021 which has worked great but is only 216Ah. The cells I have for my electric propulsion are 280Ah so if I used those and built a battery like yours I'd have 560Ah which sounds good to me! Plus they are way cheaper now than they were three years ago.
im afraid to tell you what i did, and now im scared to leave it ! i made five lifepo4 cylinder cell bats,12V 4s15p, 81 A each. i top balanced each 15p group and then balanced each 4s15p ' battery ' i hooked them up to a common bus that is switched to the electrical panel bus no fuse or circuit breaker. i guess i should put in a bms on each 4s15p bat, and a house bank 400 amp circuit breaker !? even though each boat circuit has its own breaker. solar panels through solar panel controllers charge direct to battery bus . i was very happy, although no huge loads have happened yet, with the incredible charge acceptance, but now im scared! thx herb, what a great video ! i also realize i completely misunderstood the function of bms.. i guess im sitting on a 400A bomb..
We have a 400ah LiFePo system I built a year ago which drives a 3000watt inverter for the induction cook top. The 400ah is enough for two maybe three days. The issue isn't capacity, its generation. I'm planning for a kilowatt solar array this winter so we dont run the generator as much. Also have a 140amp alternator but I hate running engines at anchor. Planning a Bahama trip 2025!
You will have plenty of Sun to keep your batteries charged with a kilowatt of solar!
@@RiggingDoctor We have 300watts now but they don't keep up. Hoping twin 450 bifacials do the trick.
When I made my battery, I bought 1"x.125" copper barstock for the bus bars. 2P4s with no overlapping bus bars. Check out DIY nickel plating. really comes in handy.
That is a skill I would like to learn!
That ring that won't come off should get covered in electrical tape while working with electricity (for the reasons you took the other rings off)
That is a very good idea! What I really need to do is get it sizes again so that it can come off, but if I build another battery between then and now, I’ll do that trick with the tape.
Herb. This was great. Well done.
I watched you making and welding those first batteries.
Hard to think that that is all obsolete.
Bill
Times change so fast!
I really, really enjoyed this series and past it along to a new sailor, brand new! Will explain later.
My boat is on the hard right now with zero batteries. Redoing all the electrical lines, their a mess. So when it's time for batteries, you'll be the 1st to know.
Keep me posted!
800Ah 24V house bank charged by 5kW alternator/ 1.2kW solar (soon-work in progress)/ shorepower. The bank is for house loads and to charge the starter and windlass batteries. We only cruise the bay (for now) and the large need(want) is aircon and convenience.
Concerns for you: AIC rating of MRBF is only 10kA. Safety standards specify class T (20kA AIC) fuse. Also, the different lengths of the negative B- will have different resistance therefore heating. Likely just a bit under normal loads but at high loads it may be noticeable. Not sure why you wouldn’t use a single cable other than space/turns. Again, safety standards would have both parallel conductors capable of carrying the full load. I’d consider mesh sheathing where you have concerns about short circuiting.
Not really mentioned but the batt cases will need to be “installed” so they cannot move if on a boat.
Pretty great demo of building a battery. There are lots of ways to skin the cat. I’m a bigger fan of an external BMS with communicating (CAN) charge/load control. Serial (in the B-) BMS solutions seem to be getting better and CAN capabilities on these can be sourced now. I would think for your propulsion needs, this could be a huge (more automated, less carbon based) monitoring/control system.
$.02😇. (Thousands of ways to do it)
Awesome Build!
I've had some marginally serious issues out of my JBD BMS modules. They don't balance too well. Also you have to turn balance while charging off or they basically don't balance long enough. Essentially the BMS balances with a paltry 50ma bleed off only. So it only pulls energy out of too full cells and doesn't put it into low ones. I have built new batteries with the JK BMS and it has an active balancer. I have not had problems with those batteries.
Good to know! The BMS from Overkill is the XiaoXiang BMS and has been reliable. The balancing is ridiculously slow though so it’s important to top balance first. The JK BMS does a good job of balancing for you?
@@RiggingDoctor Yes the JK BMS is a miracle worker. I have the JBD(XiaoXiang) BMS in my boat and my electric motorcycle.(Fly E motorcycle) The JBD has caused me a lot of headaches. My motorcycle has gone dead with 25% remaining because one of the cells reaches the low voltage cutoff and all the rest are terrific. The boat batteries always have a large deviation in voltages on the low cells. The JK BMS with the 2amp balancing current makes my cells in the overlander pretty close to perfect all the time except after pulling a lot of amps for a really long time. Even then it is usually like 0.015! If you make more batteries, I highly suggest going with the JK BMS series.
The reason I use this BMS is because of the tests Will Prowse conducted. The Daly BMS doesn’t actually have a functional low temperature disconnect. He put the probe in ice water and it kept right on discharging after surpassing the low temperature threshold. It out performed the XiaoXiang BMS in every other aspect, but the XiaoxiangBMS has better safety control of the cells which is why I chose them for the boat battery builds.
As a result of this choice, balancing becomes super critical since the BMS won’t do it for you.
@@RiggingDoctor The Daly really is pretty basic. Watch this video about your BMS the Overkill Solar/XiaoXiang/JBD. This setting change is SUPER important. ruclips.net/video/XI-8MxSgHOA/видео.html otherwise it is the off-grid garage and these keywords;Why 'Charge Balance' is a bad idea and how to auto top-balance a battery over night with any BMS.
I’ll second the recommendation for the JK. Had 6 12kwh batteries for my house (on land)… The JBD (xiaoxiang) BMS caused all sorts of issues. I swapped all for JK after researching options. Been perfect ever since. Check out off grid garage channel for some awesome reviews off various BMS’s. I’ll be doing a lifepo4 build for my Lagoon 43 and will be using JK’s for sure.
Nice work! I applaud your efforts in this regard! I am a huge DIY fan and have considered doing my own batteries. That being said the cost now has dropped significantly on drop ins. We are prepared for LFP batteries and expect to have around 1200w of solar, ~800ah @12v of LFP. I expect 4, 200ah but could also be 2, 400ah or 3,300ah. We will have all electrical galley but still have diesel propulsion with our 250a electromaax alternator system. We are holding off on the upgrade to LFP until spring of ‘26 when we move from the Great Lakes south to warmer climate! Keep it up!
The other reason to wait on the LFP is the price keeps coming down year after year
Exactly why we are waiting. We are tied to a dock for the next few years out of necessity.
I have bought 4 * 400 amp @ 3,2v, and still have to choose the BMS. I will maybe add a second set for 200 or 400 amps if I see it necessarily, I choose to be conservative (I use induction for cooking and electric water heater, so I aimed low on purpose to have a functioning system and expand based on 1 year worth of real data or so).
That’s a solid plan. Unless you have an electric motor, it would be hard to exceed the limits of the BMS. If you do find that you are exceeding the capacity of a single BMS, stacking another one in parallel will double your capability.
Get the JK BMS with 2amp active balancing. I have dual 150amp batteries. Trust me the active balancing makes a huge difference especially if cells get low. Most of the BMS's have a resistor that bleeds current from high cells only. 50milla-amps instead of the JK 2000ma. Low cells are left to rot, and that can mean the batteries shut off prematurely. Get the JK and it makes any cell variations virtually disappear.
You do not need a BMS with high amp. I have a set up with 50 amp BMS on 400 amp 12V system. I have my inverter (4000 W) connected to + through a 600 A relay. I let my BMS cut off the relay if I get imbalance more than 0.3 V between my cells.
Awesome, very well done
Thank you very much!
Great job!
Good luck! Be sure you are not underestimating the abrasion potential of the posts and everything else. Good luck!
That’s why lots of rubber insulation!
Did you mention to keep BMS connections on top of the main battery connections? I have read that was important so you don’t run high current through the BMS or other monitoring systems.
I did not mention that but that is a good point. I always build the battery and the last thing I do is connect the BMS. Since they are the last thing on, they are also the top connection.
This is very informative, thank you! Planning to put 16 3,2v 280ah cells in series to get a 14,3kwh battery bank for electric propulsion. Any tips with waterproofing that?
I have built 3 24v batteries (one in the dinghy for it’s motor and two in series for our boats motor) in pelican cases using this same method.
I’m going to be building a much bigger battery bank for the sailboat soon and the pelican cases were going to cost more than $1000 so I’m contemplating other options.
My current thought is to make a box in plywood and epoxy it to make it waterproof with a clear lexan lid bolted down and bedded with butyl tape. The power would exit the box via the same through bolt terminals. This is my current mental version and it has already gone through a few versions to get to this point.
I will be building the batteries this winter for the boat so if you can wait a few months, you can see my final version in the videos and learn from any design mistakes I encountered in the process :)
Thanks for the reply! I was also going for the plywood/epoxy option in my head. This offers some flexibility in the shape of the box all although the cells still need to be (neatly) connected and accessible. The clear lid is a nice added feature, thanks.
Looking forward to that video :) might be building mine in the same period of time, then we can compare :)
Sounds like a plan! Having the cells facing up will also let you do any changes or adjustments to the cells without removing them from their box.
Wrap a piece of electrical tape around your Masonic ring while working around open lines and terminals.
That would have been a good idea! One touch to connect a circuit and I would have been brought to still even further light in Masonry!
Those studs look like they would get hot when high current is flowing. Have you checked it?
Please forgive my ignorance, but how is this better/cheaper than just buying an off the shelf 200ah 12v LiPo4 battery for under $600. Is it the waterproofness, quality, size? Thanks for all your videos. I love your teaching style, btw.
It’s the parts that are used. There are many cheaper options, and one cruiser I know had the cheap Amazon LiFePO4 batteries (amzn.to/3sUO5KZ) and it burst into flames. Miraculously, he was able to disconnect and dispose of the battery while it was on fire and while he was sailing without any damage to his boat or himself!
This battery is built from the top of the line components using the safest BMS and the best cells. As a result, the parts alone were $1200.
Pretty much, you get what you pay for and when you build it yourself, you can select the best parts and save on the labor costs of the build by putting it together yourself.
When you consider a BattleBorn battery is about $1000 per 100ah and isn’t waterproof, this battery comes in at a nice price point for the features you get.
This is the price of a premade quality battery (amzn.to/3EFMY4u) and they can still have issues arise on them. It’s rare, but I have seen them “singe” first hand. They have good components in them so the BMS shut the battery down before anything happened. The burnt cell wasn’t discovered until tear down.
Cost wise, to get 200ah in those batteries would be just shy of $2000 where if you build it yourself, you can make a waterproof one for $1200. That’s where the cost savings come into play.
Makes sense. Thanks for the reply! When I'm ready, I think I'll give it a shot. I like knowing what's inside the box.
Be sure to protect the small monitoring wires from chafe around that front corner.
👍 good call. I’ll add some rubber under them over the cells.
Super!
What are the cost savings going this route? 20-30% after you "amortize" the needed tools, etc? There has to be some decent gain for you to be going this route over purchasing pre-made and equally waterproof batteries. Apologies if this was answered elsewhere and great vid all around.
The tools are pretty general tools that you should have on a boat, minus the hydraulic press which is very handy if you are making your own battery cables!
As for the gains of doing it yourself: you know the quality of the components in the battery and you know that it was setup properly.
Yes, a store bought battery comes with a nice warranty, but what good is a warranty when you are in a remote location with a dead battery? By making it yourself you know that it is made right and no cheap parts were used for the sake of improving the profit margin.
How about resin for perfect compression?
I would worry that it would crack under the tension. Without fiberglass in there, the resin is very brittle.
Umm, with the extra rubber to compress the battery, does the case still remain water proof? I would think the sides might expand beyond what any gasket might take up.
How much does this build weigh? I'm doing an electric dinghy and was using a 100ah AGM which worked fine but I am the only one who can lift it. Climbing into the dinghy while balancing battery on sheer of sail boat and lifting it down is going to lead to disaster sooner or later (though not as bad as trying to lift a 60 pound outboard and then put it on the transom). The 30 pound lifepo4 I am replacing it with can be handed to me by anyone on the boat. It is only 100AH. I would kind of like 200AH for the extra range but 60pounds starts to get back to the I have to do it on my own. I suspect I will end up with two 100ah batteries in the end.
For house batteries we had 200ah of agm. I found adding the extra 100ah battery we also used for the dinghy gave me a comfortable voltage in the morning before the sun hit the panels, even with some use on that battery before nightfall. Fridge, freezer, computer(s), water pump, lights, fan. Panels are a mish-mash combination (from previous owner) of maybe 300W?
What is the cost comparison? These new square cells are amazing.
The cells cost about $600 for this 200ah 12v battery.
Isnt compression no longer an issue ?
Some say that, but the best way to get a cell to ignite is to let it puff up. I don’t want to risk a burning cell on a boat.
Perhap…wrap your tools in electrical tape to prevent accidental shorts..
Yes, and your ring.
That is a good idea! I was just super careful but that’s how accidents happen. I like the suggestion!
You might get issues with those not flexible busbars. The busbars are at a angle, which decreases contact area...also those busbars are not good and can get very hot with 50A already. The resistance is too high, because of the small contact area on the battery terminals. But I like your DIY battery design.
Good points. Thankfully these will be doing small house loads so they won’t have that much power pass through them.
What would you suggest as an alternative to the solution shown to decrease resistance and increase the contact area?
Ideally two parallel battery systems sized for loads tied to a PICOGLF30KW300V2083P or 👉🏿 Aims Power Off Grid PICOGLF50KW384V240VS , 👈👍
is most practical IMHO. There are a lot of great LFP cells in the 100 - 340 ah capacity but I think the best and most practical is 110-120 VDC x 2. With a higher budget I'd build 2 x 140 VDC+
The lower voltage battery has the advantage of less PV panels on deck, so balancing between deck space and battery cell capacity first then consider higher voltage if space is adequate. Best bang for the buck hands down. I also like the economy Hybrid Inverter Charger 9.6 kW Power Output 15 kW Solar Input with a single 90-300 volt battery.
Nice video however prismatic cells DO require compression, cylinder cells do NOT require compression.
Absolutely! The people who leave gaps for “air flow” manage, but they really should be under compression because they will puff up!
You should have strapped cells together. Cells expand(puff) on their wide side, not their narrow side, as you stated.
The expanding cells will put stress on the cell Terminals because they are linked by rigid busbars.
Try again.
Why do you have 2 pos and neg cables coming off the battery? Why not just use 1 cable?
It’s due to the amount of amps that can flow. To use one wire it would need to be a thick wire which wouldn’t be as flexible and that would make the next steps difficult. By using a few smaller wires, they remain flexible and easy to position inside the box
@@RiggingDoctor thank you for taking the time to reply!! I watch your stuff often and learn a lot!! Thank you for the invaluable content!! You make a difference!
Greaaaaat
😁
What are the battery cells used in this?
And
What are the benefits of a prismatic cell over a cylinder?
Space. You don't lose the space in between the cells that's inherent when you put cylinders together.
@SuperDirk1965 that is true, but you also give up the inherent air cooling capabilities and have to provide the compression system as well. In **this** case, the Pelican box theoretically provides enough force, but why consider that at all? This does provide a method for a smaller, denser battery where space is a premium.
@@TJDST4 You can compress them with anything. Mine are compressed with a charger jammed between one cell and the battery compartment. so no loss of space. I don't have a bms either, just don't charge them above 3.4V/cell and they never get discharged too far. It's a 4S system, 12V 500Ah connected to 200W of solar. The battery powers my autopilot, the fridge and the instruments. At night it powers the lights as well and in winter the diesel heater. It's not connected to the engines alternator, the engine has it's own SLA battery.
The other huge advantage is you can build it with a set of wrenches instead of spot welding hundreds of tiny cells together!
EVE 105ah LiFePO4 Cells: www.docanpower.com/index.php?route=product/product&product_id=437&tracking=06ORmUMyyrYyEpQ2VkP7mUHWKgx9B9SeQB6gb57tAV7ag91SsfJ5D2FxQRDgTqmm
Did your last DIy battery bank crap the bed and die?
They are still going strong. This is for a cruiser in the islands. He’s going to run his whole boat on these two batteries. That’s why I’m building them as 12v batteries.
His total battery bank is going to be 12v, 440ah!
Trying to train people about how high current battery packs work, in a few minutes is a disaster waiting to happen.
That’s why it’s broken up into three episodes with an important disclaimer that you should read about how to do it as well. All the information about battery construction is the same level of information covered in “Physics I” which is taught in high school and college. The goal is not to train people how to do it but to show them how it’s done so that they can learn further and master the concepts themselves.
Why does top balancing take so long? Like, days. What is going on in there?
The cells are slowly being fully charged. It’s pretty much a trickle charge to get them to their absolute full charge level, and on a large cell like this, it’s a slow process.
If the cell is 100ah and you are charging at 4 amps, you will be a minimum of 25 hours. As you approach full charge though, the cells won’t accept as much power and charging slows down to a crawl. This is when you find it charging at 0.1amps for a few days.
It’s important to do this process all the way so that it is done right and then everything works well afterwards, but it is a lengthy process.
@@RiggingDoctor Thank you for the quick reply. I actually just came back to say never mind since you answered the question in the most recent top balancing video. Interesting stuff.
👍
You can wrap your ring with electrical tape. Much better than nothing.
As far as I'm aware the LiFePo chemistry allows it to fail below ignition temperature so they're loads safer.
Also they are self limiting when things go terribly wrong so it’s harder for them to catch on fire.
@@RiggingDoctor Fun fact: prismatic cells are just big cylindrical cells squished flat. They're still rolls inside.
You put the positive terminal on the bottom of the box...
Yep. It’s bedded in and the battery is going to be installed in a dry environment.
On dinghy batteries, I put the terminals at the top of the lid. The reason I didn’t do that on this build is the space and size requirements did not allow the size of the hold did not allow for the terminals to be mounted higher.
How do insurance companies feel about home built DIY batteries, their installation, and wiring? My understanding is insurance companies frown on insuring DIY or they will only pay a small percentage of a claim. 🤔
As always, read your policy. There should be a perils section. I am not aware of a policy that excludes this, but maybe there is one out there somewhere. The perils section for the few I reviewed specifically dealt with hurricanes, storage on land, and blue water limitations.
Li Fe Phosphate should be safe and even water extinguishable.🤔 Ive even seen them built into floodable compartments. ..
And they use them as firewalls in mixed Li Fe Li Ion packs.
Still play safe if in doubt. .. btw its still worth padding out the battery packs against the sort of g forces encountered in going through a heavy sea.. thats acceleration up to 7g according to one German manufacturer.
Safer still are the Li Fe Phosphate blade cells..
Bet your happy you dont have to faff about soldering round cells 😉🇬🇧🧙♂️
Your ever friendly mobile phone or lap top is more likely to cause a fire .. especially if left on charge.
@SenatorPerry BTW, I've read/heard boat owners who plan to install their own lithium batteries onboard are being advised to seek professional help or risk invalidating their insurance and manufacturer warranties. If an owners’ system was not upgraded and installed by an ABYC certified electrician, claims may be denied entirely. Like you said, read the policies fine print.
The trick is to make sure that what you put in your boat is bulletproof so you don’t have to deal with insurance claims.
Is this cheaper than going out to buy a LiPo battery?
They cost about $950 for a 12v100ah battery where the parts to build this 12v200ah battery cost $1200, and it’s waterproof! I would say it’s a significant savings.
👍
😎
😀👍👍👍❤
Im sad you dit not use butyl to waterproof the standoffs
The 5200 is also adhesive so that the studs are permanently in there as well. It’s double duty.
Sorry but the pressing is a joke. According to the manufacturer, it should be 300kg per cell. You have 2 cells next to each other, so it should be 600 kg
Dang that’s a lot of force!! I’m going to have to build stronger boxes then. Thanks for the information
Are you a freemason dude?
Are you a freemason dude?
I am. I became a Freemason back in 2009.