How to Salvage/Harvest Cells, Remove Old Welds

[YoshiMoshi]

Yea so measuring at the actual cells or tabs while still attached to the BMS I get very low voltage, or sometimes nothing. Mostly very old battery power tool packs that have been discontinued and might be 10 plus years old and past the shelf life. I guess it's all luck of the draw. But measuring at the actual nickel tabs instead of at the BMS I was able to find an extra pack with good cells.

 

[BlueSwordM]

Yea so measuring at the actual cells or tabs while still attached to the BMS I get very low voltage, or sometimes nothing. Mostly very old battery power tool packs that have been discontinued and might be 10 plus years old and past the shelf life. I guess it's all luck of the draw. But measuring at the actual nickel tabs instead of at the BMS I was able to find an extra pack with good cells.

When dealing with very low voltage cells, your best bet is to get them up to normal voltage (3V) at extremely low currents.

A lot of the very low voltage damage comes from bringing the cell up to normal voltage.

 

[YoshiMoshi]

Maybe the one that spontaneously combusted was one that was "revived"? I'm seeing that attempting to revive a low voltage cell less than 2.5 V is dangerous, and even if you are successful it won't have same performance characteristics. I see people on YouTube revive them though. Not sure it's exactly safe though.

 

[harrisonpatm]

Read this post and the following, but take it with a grain of salt, my experience isn't universal.