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diy solar

No BMS?

KauaiMolokai

Solar Enthusiast
Joined
Dec 25, 2019
Messages
283
This site is awesome! I have learned a huge amount from all that everyone has shared. Thank you!

Is anyone able to tell me of any dire consequences - fires, meltdowns, molten metal, debilitating fumes, or other serious occurrences - that have happened to them personally using LiFePO4 cells they built into batteries and where a BMS was not used? I've read of a number of instances of "puffed" or swollen cells, and while these occurrences might be costly or could be termed serious, they are not in and of themselves life threatening.

I'm not advocating not using a BMS, but am very interested in knowing what has actually happened that is serious which could have been prevented by using a BMS. Thanx.
 
Well .... Maybe your definition of serious is different than mine, but I would consider ruining cells serious. There is loss of money and loss of 1 1/2 to 2 months to get more cells. We generally buy these batteries and spend more on them because of the long life cycle. Why would you even buy these batteries if your aren't going to protect them with a BMS ... at the very least, buy one of the cheap Daly ones.
 
I've read of a number of instances of "puffed" or swollen cells, and while these occurrences might be costly or could be termed serious, they are not in and of themselves life threatening.
A swollen cell IS very dangerous. Swelling is what happens right before failure, which can result in fire, explosions, or gassing off toxic chemicals into your home. Or the swelling could move things around, and cause a mechanical short, which is a super fast way to get hurt or start a fire. It may not kill you, but it could ruin everything you own, and / or maim you. If you are trying to save a few bucks by skipping the BMS, you will end up spending WAY MORE on new batteries, a new house / RV, medical bills, or a bad combination of all three. At least get a cheap one, the $50 or so you spend could save you a lot of trouble.

Here's a story from someone who tried it, he destroyed his pack pretty quickly.
 
Not my own first hand experience but this is what happened to somebody's batteries when overcharged, without a BMS:
EV-Fire-February-2009.jpg

 
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