Watchit
 

I have many nimh AA batteries all stored on a drilled board. I have been recharging them with my fast Uniross express charger. I was getting a lot of failed batteries, say two out of four, two into the bin. Strange I thought, so I started charging them with a shallow charge. No probs all, so do not keep them stored for a long time. Charge them frequently. These fast heavy current chargers are the death knell to stored batteries.

Thats true.

Remember that the higher the mAh rating of a battery, the more charge it holds but the faster it looses charge - both in use and when left doing nothing. Sadly it's a fact of life with NiMH batteries.