[h0l0cube]

Then that’s more the issue with the BMS rather than the cells

[samatman]

Problems with the BMS can become problems with the cells very quickly.

[h0l0cube]

Yeah, but I would just buy the cells and spend more on a BMS. Or you can just use a low voltage cutoff and an active balancer for a smaller setup

[Aurornis]

In many of the systems, the BMS and battery are one in the same.

This article blurs the lines between the cells and battery system, too.

[h0l0cube]

The post you were replying to was specifically about cells, and if you’re going for economy, building your own packs are substantially cheaper than buying packs domestically. Also less fraught when you’ve DIYed to diagnose and fix when things go wrong

[oulipo]

This is why at https://gouach.com we've built the first easy-to-repair, easy-to-swap-cell battery! We're launching a Kickstarter soon, stay tuned (on our newsletter!)

[lazide]

Also prone to average people setting themselves or their houses on fire, eh?

[h0l0cube]

Depends on how scrupulous Average Person is being. There's codes for electrical and solar installations that can be followed, and it's best to stick to the letter, even if you're certain it doesn't apply. And after that, you should get it certified by a licensed professional, but would also need a licensed professional to hook it up to the grid

[lazide]

I think you’re misunderstanding what I’m trying to say.

I’m talking about assembling your own multi-kwh lithium battery assemblies (pre-BMS even).

One wrong poke with a screwdriver, and all sorts of entertainment is likely to ensue eh?

And they’re big enough, no portable fire extinguisher is going to make a dent either.

[h0l0cube]

> One wrong poke with a screwdriver

I'm not sure where you're jamming the screwdriver, but certainly any wrenches/tools you use should be insulated if you're dealing with very high current and/or high voltage. Enclosures, insulated wires, conduits, terminal covers should be used to avoid short circuits. Also proper earthing and circuit isolation with RCBOs to protect from electric shock and overcurrents frying the wires/you, all which should be switched to the off position when you're poking your screwdriver, eh? ;)

> And they’re big enough, no portable fire extinguisher is going to make a dent either.

If you aren't doing basic safety things and somehow manage thermal runaway on LiFePo4 (pretty hard), you're probably going to melt some copper. Probably best not to put your battery assembly near flammable things, unless you want to see the world burn like this guy (though at low voltage/high current)

https://www.youtube.com/watch?v=ywaTX-nLm6Y

[defrost]

Sure, you're saying some people shouldn't DIY.

Where I live many people DIY as a great many people have mad skills (lots of FiFo workers making a good living from O&G installions and big mining projects).

They build their own houses, their own planes, off grid power systems, water proof EV's to drive across harbour floors, etc.

If you've got a big (shipping container sized) battery pack you need a big thermal blanket to cut off the oxygen or a wide enough fire break about it.

Speaking of DIY home builds, here's a good use of black builders plastic: https://www.youtube.com/watch?v=1ILbQHnHPnY