Battery checkers

schiff

I have a battery checker. Yesterday I checked the strength of a rechargeable battery and forgot to remove it afterwards.

When I checked it, it straddled 'Replace' and 'Good'. Today it's totally flat. What technically has happened? I've read that completely discharging batteries from time to time is a good thing - doesn't it make them last longer?
But I never knew this was one way to do it!

schiff

penrhyn

A battery checker puts a load across the battery, i.e. draws electrical current from it. Thus leaving it connected for any length of time will discharge the battery.

John_Gray

It's probably worth you Googling for something like "recharging batteries" so you can find the significant differences between rechargeable NiCd (Nickel-Cadmium), NiMH (Nickel Metal Hydride) and LiIon (Lithium Ion) types.

It's not a good idea to fully-discharge the NiMH ones, whereas this was considered useful for NiCDs, to avoid the so-called "memory effect"...

John