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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