Battery Testing
 

I have several batteries, some are RC leftovers, and was wondering if they can hold a charge. The RC ones don't fit in my guns so I can't test that way.

Is there a way to tell if a battery can hold a charge and what % of a new one it can hold?

What tools do I need to do this?

multimeter

hint: the battery doesn't have to fit 'in' a gun to test if it will work. just plug it in and test fire.

but why would you want to test batteries that don't fit?

I just want to identify if the cells are any good. I can plug it in to test fire like you said, but I want to know also how long it will last.

using a charger like the TLP 15 that has a LCD display, you can discharge it and fully charge it noting what the final mAh reading is. 1 shot = approximately 1mAh.

what does it say on the side of the cell?