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diy solar

16S3P

Duke011

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Joined
Aug 17, 2021
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Hello all,

I purchased 2 24 Packs of 3.2v 25ah Lifepo4 Topband Prismatic batteries from battery hookup. I believe I have a good understanding of how to connect them to make a 48v battery. This is my first DIY batter so I wanted to reach out to those with experience to see if one of you could send me a photo schematic of how to put them together in a 16S3P configuration.

Thanks
 
I'm building 8S, but I based my build partially off the Overkill BMS manual. Here is what they have for a 16 S Build.

1632007298009.png
From here its putting three batteries in parallel. This is the diagram I am using for my 280 ah 8S build where two of them are in parallel. Not Included in the pic are two fuses for the individual batteries on the red wires to the busbar.

1632007439566.png
I just used my 8S topband pack today for the first time.
 
would I have to get three BMSs? That gets pretty expensive.
I would think you could get away with one BMS since you're running 3p. I would think the cells in parallel would stay almost perfectly matched.
 
I would think you could get away with one BMS since you're running 3p. I would think the cells in parallel would stay almost perfectly matched.
So if I used one bms how would I install it? Would I pick one of the three 16s? I now understand how I will configure the battery but still unsure how to connect the bms. If I only had one 16s I think I have that down but still unsure about several in parallel. Thank you both for helping this newbie.
 
Take a look at this thread you might want to think twice about just using one BMS.

 
Take a look at this thread you might want to think twice about just using one BMS.

Thank you
 
3P16S has its problems also. May save on BMSs, but you lose the ability to monitor individual cells. Now you’re monitoring groups of 3. One lead to three cells in parallel only lets you monitor that one set of 3. You also lose redundancy so if one cell is bad, now the entire battery must be brought down until trouble shot and fixed. If this makes you buy busbars this gets pricey.

If monitoring individual cells is important or not, I’m not sure. I built my first Lithium and this does not allow any monitoring at all. It’s shutting off and I’m not sure why.

I thought about 2P8S for my build, but I did not want that single battery pushing the 200 amps peak or 100 amps Continuos. Part of the problem was a single BMS would handle all that power. I chose a 100 amp overkill BMS with each battery providing 50 amps continuous or 100 amps peak. Also, if I have problems with a battery, there’s some redundancy where I take one battery out and watch my power consumption, but I still have power while I troubleshoot and wait parts.

With the price of copper now, the busbars may outprice that second BMS. I was pricing 1/4” X 3/4” copper busbars for my build yesterday, and I want at least 6’, but the price I found on E-Bay was $184. If your batteries come with busbars, probably not a problem, unless when you install them 3P and they’re different than delivered.

I’m not saying 3P16S is a bad idea, just a bit more to think about in the build. For me, with all the work and time that goes into it, purchasing the second BMS was easy.
 
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