[zimpenfish]

> However, the 18650s have no internal electronics to prevent any charging mishaps.

I believe you can get ones which do have this - e.g. https://www.amazon.co.uk/Canwelum-Protected-Lithium-Battery-...

"Reliable 18650 Battery: Integrated with protective board, avoiding overcharge and discharge, protecting your led torches or head torches. "

[gm-conspiracy]

Says 2250mAh, but do not use in e-cigs.

There was also this project on hackaday to make a "topper", but it would not work w/ leaf spring battery connects because of the increase in height.

https://hackaday.com/2017/09/25/diy-lipo-protectors/