To get the best from your rechargeable batteries :
- Buy a good charger. Make sure you get a “smart” charger, one that electronically monitors the recharge process and prevents overcharging. 
- Remove the batteries when the recharge is complete. Unnecessary time on the charger means more “trickle” power is used to keep them charged. 
- Don't regularly discharge your batteries completely in an attempt to make them last longer. Complete discharge can actually shorten their lifespan. 
- Store your NiMH batteries at room temperature in a dry location. Excessive heat can definitely damage your batteries and cause them to lose charge faster. 
- Consider using low self-discharge NiMH batteries, which don't lose power as quickly when sitting on a shelf. If your rechargeables are ready to use, you're less likely to fall back on the throwaways.