NiMH AA battery discharge curve
NiMH AA battery charge and discharge curve.  

This particular rechargable AA battery (Rayovac NM715), rated for 1600 mAh, had been used for some time and was almost dead when I started recharging it. It tested at 49 mAh, just 3% of rated capacity. Surprisingly, after several slow charge and discharge cycles (~200 mA charge, ~100 mA discharge) in the LaCrosse BC-900 charger, it progressively recovered with the last discharge nearly matching the original marked capacity.  I had previously charged it using a fast charger (Rayovac PS4 "1-hour" charger) which may have damaged the cell by overheating.

The BC-900 has a LCD display but does not store or transfer data externally. The voltage plot above was measured using the Radio Shack 22-168A multimeter with serial interface and provided Scopeview software.

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