Flashlight flickers when using old batteries.


Newly Enlightened
Sep 15, 2011
Something that I've noticed, I have a bunch of high quality Tenergy/Panasonic 18650 batteries that I use with my flashlight and I use a Pila IBC charger to charge and maintain them. With these quality batteries the flashlight always works great, providing smooth flicker free light.

However, I also have a few dozen of old 18650 batteries that I pulled from bad laptop battery packs about 12-15 years ago. If my memory serves me right, these battery pack would no longer charge plugged into the laptops, so I disassembled them, and each individual CEL was able to take charge with the Pila charger. I've kept them for emergency use, charging them up every few years, but at this point they are so old that I decided to get rid of them. I put them into the flash light, and as they get depleted over time I just dispose of them instead of trying to recharge them. Over the last two months I think I'm on my 3rd or 4th battery, and I notice the flashlight seems to flicker a little, even when the battery is fully charged, especially on full power mode. Is it something that old/bad batteries can cause?