Have you EVER fully discharged them?

A good battery conditioner will probably fix the majority of them but they still have a limit on the # of cycles they can handle.

Also there is a HUGE difference in battery quality between cheap expensive rechargeable.


I used to be into high end Electric RC Cars and would go through batteries, and wow there are TONS of different things to check when buying batteries... capacity, cell manufacture, rated # of cycles (normally related to manufacture and then the level battery you buy.)

Also charging, and making sure they are discharged prior to a recharge even though they don't need this it helps.

ETc Etc