3 ms·

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).

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.

zimpenfish 9y ago
> 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-Rechargeable/dp/B071VVZM8F 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 9y ago
  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/ https://hackaday.com/2017/09/25/diy-lipo-protectors/
leggomylibro 9y ago
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 9y ago
  Check this out: https://hackaday.com/2017/09/25/diy-lipo-protectors/ https://hackaday.com/2017/09/25/diy-lipo-protectors/
  - leggomylibro 9y ago
    Oh, sweet - thanks!

zimpenfish 9y ago

> 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-Rechargeable/dp/B071VVZM8F 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 9y ago
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/ https://hackaday.com/2017/09/25/diy-lipo-protectors/

leggomylibro 9y ago

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 9y ago
Check this out: https://hackaday.com/2017/09/25/diy-lipo-protectors/ https://hackaday.com/2017/09/25/diy-lipo-protectors/
- leggomylibro 9y ago
  Oh, sweet - thanks!