How to tell if a battery is borked?

Ref the Lumi LED post; I think my battery may well be defunct since it wouldn’t run my new LED Lumi on high for more than about 10 mins and then switched to med and refused to go higher.

Apart from this empirical evidence, is there a way to tell for sure. It’s supposed to be a 13.2V / 4.1MAh pack, if I plug it into a multimeter what would I need to look for (I’m not a sparky sort of person btw, would get someone to look at it for me)

Assuming it is screwed, any way to rescue it? I bought it off someone on here a year or so back and I’m not convinced it is OEM, so testing Lumi’s legendary customer service might not be a go-er.

Did you run it while not moving, or on a ride?

If so, it will probably be the temperature cut off as the LED overheats.

Joe

Is it Nimh or li-ion? Does it work ok with your old lights ok?
Dunno if it maqkes a difference but you have to re programme the light to suit Nimh batteries, why i don’t know, and if it makes a difference i don’t know either??

used on a ride and yes, I did rtfm and have reset the light to be NiMH

any advice on battery borkage greatly received. I know there are enough homebrew LED operators on here so there is enough electronics knowledge about – show your faces please!!!!

Charge it up, then if you’ve got a multimeter check what the voltage is. It should probably be about 15-16v.

In terms of fixing it, if it looks like it is a dead cell, you can check all the cells individually. You’d have to take it apart, and then measure the voltage across each individual cell, then put it back together with a replacement cell. It’d be a right hassle though. If there’s any chance it is a lumicycle battery, they can check batteries and fix them, although it does cost money.

Joe