Safe lithium battery circuit design

[solderandchill]

I’m working on a small power pack and want to prioritize safety. What protection features, such as fuses, BMS, or thermal cutoffs do you think are crucial for lithium battery circuits?

 

[Alan]

Make sure to include a BMS for balancing the cells and protecting against over and under-voltage. Also, don't forget about fuses and thermal cutoffs to ensure safety from short circuits and overheating.

 

[whitet1ger]

when it comes to safety, redundancy is your best friend. I always use a BMS for the smart protection but back it up with a physical fuse on the main positive lead
fuses respond to raw heat and current in a way that software sometimes can't. if the BMS fails in the "closed" position during a short circuit, that fuse is the only thing standing between you and a fire

 

[oldgeek]

If safety is your main concern, and it should be, buy a ready-made battery pack and charger made for a power tool. You haven't said what you need in voltage or power, but the Milwaukee M12 batteries are small and provide around 11V at 2.6A surge. You can connect to them with male faston connectors. Hard to beat for a fully tested, warranteed battery. Ohter brands have comparable batteries, some going up to as much as 80V.

 

[Alan]

Solid advice. Using a pre-made tested battery pack is by far the safest and simplest option for any DIY project.