NiMH batteries come in standard AAA, AA, C, D, and 9V sizes. They hold much more power than a standard alkaline battery, can be recharged up to 500 times, and cost under $2 for AAA and AA. NiMH batteries self-discharge at a rate of 5-10% per month. To keep a full charge NiMHs should be recharged often and unlike NiCd batteries do not have a memory effect. They can be fully charged in as little as 15 minutes. A high quality charger will get the best performance from the batteries.
I use the La Crosse Technology BC-900 AlphaPower Battery Charger. This is a high quality 4 channel charger for AAA and AA batteries. It has several benefits over other chargers.
- Variable Charge Rate - it can charge the batteries at 200-1800 mAh and has a heat monitor.
- LCD Screen - The information given lets you quickly know the state of each battery.
- Multiple Modes - Charge, Discharge, Test, and Refresh modes. The refresh mode has saved several of my batteries.