BroccoliFarts

joined 1 year ago
[–] BroccoliFarts@lemmy.world 0 points 1 year ago (1 children)

I do this on the side, buy bulk low cycle lithium ion cells, spot weld them together into banks, and make larger packs.

What is the biggest safety problem seen with these?

My packs are 64P, right now 4s but hopefully 7s soon.

My main safety features are per-cell 5A fuses, 100A fuse on each bank under the battery wrap (not removable without cutting the wrap), and keeping the cells and nickel strips under a layer of kapton tape, followed by an ABS plate I designed and printed, then all the wiring, taped to the ABS with kapton tape. Which is then inside of the battery wrap. I use a lower current circuit breaker on the whole circuit.

My layman research suggests that loose wires are the main reason for fires, so all wires are taped down, and the nickel strips are protected from stress. A cell shorting out should blow the 5A fuse. And if I'm careless and bump the two terminals to a conductor while moving it, there's always a 100A limit. I also only use low-cycled matched cells and currently am charging to 4V and discharging to 3V.

Any other things I can do to make it safer?