Building LITHIUM Batteries [DIY] For Our SAILBOAT 

Hi Allyn, I actually did insulate between the cells... it didn’t make it into the video. I will include it in the write up. However I used thin plastic cutting boards. They are only about 1/16 thick!

By the way, thank you!! I put a lot of time and thought into this build!!

​@@SaltyEscape I would probably include air gaps, and airflow for cooling. Heat is one of the biggest problem for batteries. You can also think about if one cell catches fire. For that case, I would think about some fire proofing between the cells, to prevent the fire consuming all the cells quickly. I like that the BMS is outside, but there also it seems that one side is touching the wood casing. Airflow for cooling would be great there, and wood is not the best choice against fire. Fire is anyways one of the biggest danger on a boat.

@Sonnell if I may, I’d like to discuss some of your suggestions. I understand your thought process regarding airflow and passive cooling however none of the commercially available batteries are built that way. They are all fully inclosed in a plastic (flammable) box with packing foam surrounding them. Commercially assembled batteries have no internal fireproofing. As for heat, I’m my experience these batteries do not get hot. The hottest I’ve seen them is around 100 degrees Fahrenheit and that’s with bulk charging from shore power. My batteries have been in service now for nearly 2 years. Also, the risk of fire with Lithium Iron Phosphate chemistry is extremely rare. A deep cell lead acid battery is much more likely to catch fire compared to LiFePo4. My design allows for air cooling from the tops of the batteries and allows for inspection of the terminals to ensure the terminal bolts stay tight over the course of years of service a feature that almost none of the commercial batteries offer. Also my design offers compression of the cells which will increase their lifespan. (Commercial batteries don’t do this either) If you have an opportunity to build a battery bank like mine please send me pictures! I’d love to see your design. Corey

@@SaltyEscape Hi, thanks for the reply. My comment was not a criticism of your design, but suggestions for improvement. Even though the LiFePo4 cells are less likely to catch fire than the more common LiIon types, still, fire and overheating is the biggest threat. The commercial ones I saw, usually have 1-2 cm space around them, the foams do not fill the entire cavity. If you use them heavily, they can get hot. But since fire is the biggest threat on a boat, I think, even if the chances are not high, cooling and fire proofing is very important. Some of the commercial, even the cheaper ones do have steel rods to compress the cells, however I am not sure if this type of cells benefit from compression, maybe the pouch ones do? Or both? I am not sure. So again, I do not think I said that your design is bad, there are nice aspects of it, but I think sharing suggestions and different thoughts is always a positive thing.

Hi Thomas! Thank you.. We went with this configuration for two reasons. First, physical space on the boat was better for smaller units and second, at the time the BMS technology seemed to be more for the 100 -120 amp versions. Daly wasn’t well known at the time… fast forward a year and they seem to now lead the market. I was unsure how well the batteries and BMS units would work and a modular design would serve to easily take a battery pack out of service if needed. I am happy to report we have had this installed for over a year now and they are working extremely well. I spoke with the nice people at battle born because I bought my Victron multi plus from them and they were very helpful for programming parameters for my BMS units. Reach out anytime if you have any other questions! Corey

Thanks Tammy and Todd!!

Thank you Phil!! , Corey

Thank you!! We spent about 2050.00 on the batteries and about 400.00 for the BMS’s. The prices fluctuate. We have 1400 amp hours. For the same amp hours with Battle born batteries would be about $13500.00. The BB batteries have EXCELLENT build quality but they are super expensive AND they would take up a larger footprint. We sized our system large, so if we have a failure we can remove the failed unit. Replacement BMS is a great idea. Thanks again, Corey

@@SaltyEscape so you paid even less through alibaba. 500 a battery. That is just amazing. Hope they they serve you well for many years to come. I will probably do the same as you when time comes.

If you calculate the cost per amp hour it’s better yet. 😊

These have been working like a boss! We lost power a few weeks ago and didn’t know it because the Victron switches over instantaneously. The batteries kicked on and we never missed a beat. If you need help let me know!

We’ve watched many of Wills videos. He does a great job. The milk crates are great for a Mobil set up like on a fishing boat for example however they won’t work for me with space limits. 😉 -Corey

It’s been about a year since I built the batteries. As I recall, the screws bottom out. I’m due to check everything over (to insure everything is still tight). I’ll check them out! Thank you. I only noticed one comment, you mentioned two… Did you see something else that I should change?

That’s a good idea to have a thread in the DIY solar forum. I have spent a lot of time reading on that forum but no, we didn’t start a thread.

Hi Tom, Great questions! It’s very hard for me to answer the question about 1400 amp hours and whether or not it’s enough for us… I think so… I made another video talking about how much power we consume. Basically we took the boat out and use the batteries overnight. We did not try to conserve. I remember talking about exact numbers in that video but I seem to recall we had just less than 50% capacity after 24 hours. Keep in mind there was no recharge effort. We did not have any solar operational, we did not run the generator and we did not have the Orion converters for our alternators. We tried to base our amp hour bank off of other RU-vidrs such as Gone with the Wynns. I seem to recall they only have around 1100 amp hours and they are heavy consumers of power like we are. Regarding the wooden boxes. They have been performing well, one thing that did not make it into the video is I used them pieces of plastic as spacers in between the batteries. These were cheap cutting boards I found at Walmart, maybe 1/16 inch thick. The purpose was to prevent any eventual wear and causing the batteries to sort out to each other… I doubt that would ever happen but I saw someone else had done this so I did it as well. Regarding compressing there are many RU-vid videos that look at this in depth. By my calculations the lithium batteries should live for about 10 years at still 80% capacity. If you put them under compression you may be able to squeeze out some more time. My logic with the boxes is the batteries are tight and if they should expand it won’t allow them any room… Pseudo-compression. How about sending me an Email.. that way we can converse a little easier and share pictures if necessary. Also, I heard from one of my friends in the Marina who has a Monk 38 Who tells me he has plans to sell it sometime in the next few months. They just returned from the Bahamas. Talk soon! SVSaltyescape@gmail.com Corey

Sorry Monk 36

The data sheets and information online shows -20 to 60 degrees C. Those are very extreme. We have ours programmed to shut off at 0 and 55 (on our specs). I hope our boat never reaches either of those temperatures. 😊. Also we are installing the batteries under a bed, near the waterline. This should help to keep them cooler.

@@SaltyEscape Hello from Tulsa, Oklahoma. (The furthest Inland Port in the USA, Marine Hwy M-40 "The Port of Catoosa") We got to -13 degrees F below freezing this year! With the weather patterns changing around the planet, the freezing cold could become a problem. However, since that puddle jumper of yours is mobile I doubt if you would have any problems. I would consider some type of heating arrangement for the batteries.... Just because Mother Nature does not have a sense of humor! (Waves)

Yeah... If we ever plan to be in a place with temperatures like that we would pull into a marina and plug in. Of course there are people installing low draw silicone heating mats to keep things warm for extremes. I’ve only seen this in the RV world so far but we would certainly be willing to implement them if needed. We definitely have the amp hours to account for the draw. Nice talking to ya! Cheers.

@@SaltyEscape I'm no expert so maybe not a sufficient cause for concern, but don't the batteries generate heat when cycling that could build up in enclosed space?

A few of the main cables get warm, not hot, and only when we’re doing a heavy charge, like when we ran the capacity testing. Under normal operation we have not seen the system get warm. The BMS have an overheat shutdown temperature probe so we know if there is a temp problem. Hope this helps! Corey

Hi Kevin, yes my plan was to install simple rope handles. Easy enough to do at any time by drilling holes in the wood and threading rope with knots to hold them in place. However I don’t plan on moving the battery packs once they are installed and they are not so heavy that I cannot easily carry them. Each box weighs under 50 pounds. For now, I’m going to leave the handles off. Thanks for reaching out to us! -Corey

Hi! Yes, in the video description I have a link to our Amazon affiliate store with both the BMS and the Batteries. Good luck! Corey

Hi Kevin, Thank you! I am not compressed directly. I thought a lot about compression and like you mentioned, there are at least two schools of thought. I asked the Alibaba contact and she seemed confused but eventually stated the bus bars are spaced correctly... lol. I chose to build these boxes with 3/4 plywood and I built them with very tight tolerance. My idea was to create a stout confinement for the cells because I have seen they will expand and contract during use. While They are not truly compressed, they will apply pressure to each other during the expansion creating a pseudo compression… At least that’s my idea. As for the top balancing to that specific voltage, honestly I am not sure. I suspect my batteries have come manufactured at a slightly lower voltage than previous generations and therefore I am finding conflicting information on the DIY forums. I think the most important part of the programming is the safety cut off’s. I’m considering making a quick follow up video because there have been a lot of good questions, as you saw. Thanks for reaching out to me, let me know if you have any other questions! Corey

I’m interested in seeing how others are dealing with protecting the alternators if the BMS shuts down the battery due to a cell hitting high volts. My plan to address this is keeping my lead acid bow thruster & windlass bank and the start battery as well. Will charge (with solar and alternator)the lithium and lead at the correct rate for the lithium. Will top up the lead with a DC-DC charger with the lithium as the source from time to time as needed. We are setting our boat up for extended periods at anchor. If the first shipment of lithium performs well we will add another 4 or 8 cells. Cheers

I am keeping the lead acid for the engine starter batteries and I am using the Victron Orion dc to dc to flow from the starter batteries to the lifepo4 house bank for charging while the engines are running. I think this is the easiest way to utilize your alternator to charge the lithium batteries. As you know, the internal resistance of lithium batteries is quite low, therefore it feeds through the lead acid battery first… I am actually working on this part of the install this week. Our catamaran was previously set up with lead acid house bank and lead acid starter batteries, they were all tied together with emergency switches to re-route power and a lot of redundancy. It has actually been quite an undertaking to dismantle it.

Yes I considered going through the starter but my thinking is I would then not take full advantage of the capacity of a Balmar high out put alternator and regulator as the DC -DC limit of only 30 amps. So I decided to use a Victron 200 amp 3 bank isolator. In this way I have the ability to maximize charge rate to the lithium. Once the lithium is full I can top up the lead. I’m sure both our strategies will meet our needs. And I understand the pain of ripping out various systems. I’ve have replaced 80% of my AC&DC along with most of the instrumentation. But it’s also a lot of fun. Cheers

Hi Douglas, this is an excellent question! The batteries are measured in amp hours, in other word, this means how long can you draw on the battery. If you have an appliance that draws one amp per hour you could run that appliance for 280 hours. The BMS is measured at amps. (Not amp hours) This is how much current you could pull through at one time. We have five battery groups, and each has its own 120 amp BMS. This means I have the ability to draw a maximum of 500amps, at one time. This is significantly more than I ever expect to draw. The same principles apply to charging effort, I don’t expect to have 500 A coming in at any one time. I hope this helps, thanks for the question! Corey

All of the Boat builders have gone to lithium iron phosphate. Insurance was not a problem lead acid batteries have a higher risk than lithium iron phosphate chemistry.

Thank you Andy!!

Thank you Micheal!!

I’m going to look right now! Thank you!!! Corey P.S. “This is the way…”

@@SaltyEscape 😂 You’re welcome, let me know how you make out

@@vandalorian8777 IT WORKS!!! This is going to make it sooo much easier!! Thank you!

@@SaltyEscape Glad I could help. Looking forward to seeing how much solar you are going to be able to install. My advice would be to install as much as possible. I would consider installing panels aft of your cockpit roof over the dinghy. A gaming computer can use as much as 500w 42 amps per hour😳

We have 4 Panasonic 320 watt rigid panels and 4 120 watt flexible panels Hopefully that will be enough. Hopefully We will get our arch soon to go above the dinghy exactly how you described and we’re talking about converting our cloth Bimini to a hard top Bimini for the flexible panels. All of that should be installed over the winter. 🤞 Still waiting for some supplies to come in and waiting for enough funding to purchase the arch

Haha. Nope, no idea.

What links?

@@SaltyEscape amazon ones

I clicked into it and it appears to working. If Amazon changes Something their end the products will say unavailable and I need to change it. But they don’t tell me. Would you mind sharing specifics so I can fix it? This video is about batteries so I looked at those links. I’ll check the solar panels.

Okay, so the only things “unavailable” are the sun power 110 watt panels and the battery BMS. In both circumstances they have been factory discontinued. I am changing my links to similar items. Thanks for letting me know and trying to use my links. 😊