DIY LiFePO4 battery assembly

[shade]

Get bare LIFEPO4 cells - maybe LiPo if only to be used occasionally, choose the ports / electronics to suit your needs, and buy a Pelican knockoff box to enclose it.

Where's a good place to find a guide on assembling a battery in the 100-200Ah range?

I've seen many references to doing this, and I've snooped around the web for a guide to producing my own battery. I've found some guides that include advice on harvesting used cells from laptop batteries, and beating copper plumbing pipe flat for interconnects, but I'm not interested in taking that kind of approach. I'm willing to spend the money for known-good new cells, proper wiring, and respectable management controls.

Is it possible to create a DIY solution that rivals a Battle Born G31 in quality for less than their price of $950? Proper tools would be a factor in the total DIY cost.

What kind of flexibility is offered by a DIY solution? I have a space inside my truck's cab that could work well for a battery compartment, but it's roughly 48" x 8"x 8". I may be able to squeeze a pair of BB 50Ah batteries in the space, but maybe not.

Thanks for the advice.

 

[dreadlocks]

Well clearly you can make it to fit whatever footprint you wish, and you'd have access to each cell and series of cells, you can in theory anyway keep a closer eye on things and thus perhaps be able to provide them a better life .. but, as you already know.. that might not be worth alot if one cell still manages to ruin everything.

Having a BB, and having made some small LiPo packs before.. I think I'd break down if I needed more capacity and build one.. probably ~100AH-200AH of 24v, just to cut the inverter loads in half.. and I'd be building it my self because there'd be a pretty large gulf between DIY price and cost of 4x100AH 12v LFP's.. but any less, yeah I can save a few hundred bucks, but after all the design/build/testing time and dealing with locating legit, top quality cells is sunk it'd probably end up costing more, especially if I charged my self what I charge my employer per hour... If you go all top grade components and over engineer everything you might not even come out ahead, and if you do its probably long in the future when you need to rebuild it and can reuse everything but the cells.

There's some guys here whom toss shade at drop in LFP's, but I think most of the misgivings is due to poor marketing.. If you really do just drop it in and treat it like a lead battery your setting your self up for a world of hurt and are not going to see the longevity claims made, but if you treat it like a LFP and just want a plug-n-play setup that works out of the box and keeps everything simple they are rather good IMO.. I dont rely on the BMS to keep me safe, its just the last line of many layers of defense.

 

[shade]

That's what I've seen so far. If I was building a large, off-grid battery for a structure, I might consider using less than stellar cells and other cost cutting measures, but I don't think that's a good idea in an environment as harsh as a vehicle. I can't see myself ever wanting more than around 100Ah / 12V capacity in this vehicle, so it'd be harder to justify the time, trouble, and expense (I don't own a spot welder) for that small of capacity.

Like a lot of tech, I'm guessing the early days of aftermarket lithium battery options for vehicles was filled with even more sketchiness than what's seen today. I know the Schwab sourced or similar LiFePO4 batteries are top tier options, and they're certainly nice, but I think I can live with a Battle Born battery tied to a good management system.

Other than Battle Born, what other manufacturers offer similar quality & pricing from a decently established company?

 

[luthj]

If you are going the DIY route, I would suggest looking at prismatics. For budget minded folks the frey battery company sells direct from china, and there are several importers who rebrand them (usually a light blue aluminum cased cell). You only have 1-2 cells in parallel, which makes assembly much simpler. From there you need a basic BMS (balancing circuitry is not often needed). A disconnect relay, and good charge source will handle the rest.

 

[hour]

Other than Battle Born, what other manufacturers offer similar quality & pricing from a decently established company?

Victron has lifepo4 batteries for a couple hundred more than the BB, which might be cool I guess if you have any of their other gear.


Check out this video. He's been finding some names I've never heard of and some test well (check out his other videos too, I think he's reviewed quite a few in last 2 months). You stand to save maybe $350 over Battleborn buying a china drop in. Who knows with the warranty.

I have a 90ah DIY with prismatic cells and I would have just bought a BB if I could go back in time.

 

[dreadlocks]

I went with BB large part because I was in a rough spot and needed a battery fast, and could same as cash finance it through amazon.. now looking back I'd of spent a lil more and got a Victron since I otherwise bought fully into their ecosystem (disconnects/inverter/solar/monitor).. id have me a lil rpi color display.

 

[shade]

I'm sure there are some good buys to be found from no-name sources, but I'm not going to bother with them. I'd rather pay more up front and not have problems. I'm watching some of Will's videos. Seems like a sharp guy that's interested in data more than boosting his opinions.

I'm considering a Victron charging system, so that would make sense. Do their batteries interface better with their other gear better than using a non-Victron battery? Who's a good retailer of their products?

 

[hour]

I'm sure there are some good buys to be found from no-name sources, but I'm not going to bother with them. I'd rather pay more up front and not have problems.

I'm considering a Victron charging system, so that would make sense. Do their batteries interface better with their other gear better than using a non-Victron battery? Who's a good retailer of their products?

Well, their batteries have bluetooth built in... so to that extent, yeah. I think they also have some products that only pair with their batteries (miniBMS) but I can't even understand their gear sprawl anymore. Ex: aren't the features of the miniBMS also built in to the battery anyway? Whatever benefit I'd get out of a Victron battery (like being able to see individual cell balance remotely) wouldn't matter, because I wouldn't be concerned over that like I am with my DIY battery. I'd probably still get the BB battery and save a little, even though I'm deep in with Victron gear.

In short, I think you get to spend more money only to then spend even more money going with a Victron battery. My BMV + BatteryProtect + SmartSolar victron stuff is more than adequate for my needs and doesn't care about battery.

 

[LandCruiserPhil]

I have a Victron 100AH lipo and charger and like the protection Victron offers along with everything being bluetooth.

 

[MapJunkie]

Victron has lifepo4 batteries for a couple hundred more than the BB, which might be cool I guess if you have any of their other gear.


Check out this video. He's been finding some names I've never heard of and some test well (check out his other videos too, I think he's reviewed quite a few in last 2 months). You stand to save maybe $350 over Battleborn buying a china drop in. Who knows with the warranty.

I have a 90ah DIY with prismatic cells and I would have just bought a BB if I could go back in time.

I recently built a 90Ah battery using ebay Valance batteries for $350. They were still in shrink wrap! They rock, though they are likely hard to find used now that Will did a video in them. DM me if you have specific Valance questions. I went deep down the rabbit hole on these.


Sent from my iPad using Tapatalk

 

[dreadlocks]

Victrons have built in Balancing/Temp/Voltage control, but everything else is farmed out to an external BMS.. that way multiple batteries can be chained together off same BMS.. that BMS has Can bus IO that can be used for further control externally.. all that is open sourced, or you can buy their off the shelf controllers.

 

[luthj]

While they have not been on the market long Trojan is a big long term company, so there offerings have some weight.

Trojan Battery Company

 

[Wyuna]

Others have provided some good information

It doesn't look to hard to make up a 4 cell 12 volt battery with a simple BMS, i considered making up a 300ah pack

But i ended up just getting a 240 ah Lithium drop in, as it was cheaper to just get a drop in than make my own at the time.

I'd already planned for lithium battery with my Votronic system, the drop in battery was easy to integrate, will it last, time will tell, i'm only one year into the two year warranty.

Im interested in the Victron Batteries for my next camper build, although they are pricey here in Aus, but the fully changeable setting with their hardware is quite nice to have and worth exploring

 

[deeznutz206]

I built 2 packs using 26650 LiFePO4 K2's!
4S12p @ 40 AH and 4S8P @ 28 AH

 

[jonyjoe101]

As far as building your own lifepo4, it could be done, but you need to build a small one first to learn the basics of how everything goes together, you need to have good soldering skills, maybe use a spot welder (cost 100 dollars for a 12 volt one), learn how to connect balance wires/fuse wire, wire up a bms. learn to charge/discharge/balance the battery. Once you got that figure out, its no big deal building a 100ah battery or even larger. I have a 220ah lifepo4 (160 cells total)house battery (2x110ah batteries connected together). I built 2 years ago, total cost for the 160 cells was about 320 dollars the cells were old stock thats why they were cheap but battery still use daily.

This a picture of my latest project 3x 10ah lifepo4 jumppacks (4s6p 26650 cells), I also built a 30ah lifepo4 batterypack using the same 26650 cells. Once you build your first pack, You can build any type/size battery you want . On ebay you can find deals on new lifepo4 cells, there are different type of cells, high discharge,low discharge depending what you want to run with them. On my jumppacks I'm using a 25 dollar 80a constant (450a peak) bms. For a regular powerpack I might use a 10 dollar 30a bms. I paid about 90 dollars for my tab welder online (malectrics) it runs off of a 28ah agm battery i have. On new lifepo4 cells a tab welder is needed, those cells are difficult to solder, tab welder makes the job so much easier.






DC 12 volt tab welder malectrics version 2 (they sell version 3 now for same price but large improvements) , I use the xt90 connectors to connect to my 12 volt agm battery. This welder gives me good welds on power setting 4, it maxes out at power setting 9, its got plenty of power.