[ButchDriveshaft]

The LiPO packs were quite popular for some time in regulated mods and in some cases still are. You can do a lot of reading on the subject if you desire, but generally the 18650 is still king due to availability, performance, and easier hotswap/battery sled charging.

[gm-conspiracy]

Lots of laser pointers and even LED flashlights from Walmart support 18650s (they also have a 'cartridge' that can use 3 AAA batteries in place of the 18650).

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

[leggomylibro]

That is a good point. What's a good LiPo protection circuit look like? Some googling led me to some basics that a protection circuit should have, does this look about right?

- Overcharge protection (prevent charging past the max voltage, probably ~4.2V but intentionally shrinking this window might prolong cell life)

- Short circuit protection (Like, a fuse? Would a PTC one work?)

- Limit charge current (0.5-1C for LiPos, 5-10C for LiCaps, etc)

- Undercharge protection; prevent discharge past a 'low voltage' value and (ideally) permanently disable cell or severely limit charge rate if voltage drops below the minimum safe value.

- (Ideally) Balance voltage between individual cells.

[gm-conspiracy]

Check this out:

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

[leggomylibro]

Oh, sweet - thanks!

[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/