I have 2 single cell AA flashlights that stopped working. One is a Fenix LD11, the other is a Thorfire TG06. Both worked with 14500 3.7v Li-ion batteries as well as 1.2v NiMH and 1.5v alkaline batteries. About two months ago the Fenix stopped working. Last night I took the 14500 battery out of the Thorfire to charge it and put a Li-polymer battery in it and it stopped working immediately. I tried other batteries with no luck. I’ve had the Li-polymer battery for years, maybe 9 or 10, and it keeps it charge a long time. It was the first battery I bought with a micro-USB port on it. On my battery meter is shows 1.51 volts, 395 mOhms. A similar EBL AA 1.5v Li-ion with micro-USB, bought about 2 months ago, shows 1.51 volts and 3 mOhms. I don’t know much about electricity but could the mOhms be the problem? My understanding is that Ohms is the amount of resistance in a wire. In general a tv coax cable needs to be 50ohms and a cb radio coax cable needs to be 75ohms. I don’t know how that works with batteries.
Could the Li-polymer battery be the reason these lights died? I don’t specifically remember putting the Li-polymer battery in the Fenix but I may have. I only have one and it seamed a good fit to put in a single cell AA flashlight.
Other than trying the flashlights with other batteries, is there something else I can test or check?
Thanks