Capacity Test of Popular NiMH AAA Rechargeable Batteries
There is very little independent data on the discharge capacities of popular AAA NiMH batteries. Most of the attention has focused on the AA size batteries. Yet, AAA size batteries power an ever-growing list of gadgets that include not only cameras but MP3 players, Bluetooth headsets, cordless phones, remote controls, etc.
There has been a tremendous improvement in NiMH rechargeable battery chemistry in recent years resulting in higher effective capacities. However, measured capacities of NiMH batteries still often fall short of nominal (named) capacities. This shortfall has been well-documented previously by other investigators studying the AA size. Prior to the availability of low-cost chargers with testing circuitry, consumers often were left in the dark as to the gap between nominal and discharge capacities. In the table below are results for five batteries from four different manufacturers.
| Brand and Nominal Capacity (AAA) |
Measured Capacity (mAh) | Measured Capacity (%) | End Voltage (V) | |
| Konnoc | 900 | 698 | 77.6 | 1.44 |
| Moden | 1000 | 789 | 78.9 | 1.45 |
| PowerEx | 900 | 840 | 93.3 | 1.45 |
| Sanyo | 900 | 873 | 95.8 | 1.45 |
| Sanyo | 1000 | 930 | 93.0 | 1.46 |
As expected, the major brands (Sanyo and Maha PowerEx) turn in the best performance. However, not as good as with the AA size batteries where Sanyo and PowerEx are getting closer or actually hitting their nominal capacities.
Why not test Sony, Energizer, or Kodak batteries? These brands are typically re-labeled Sanyo batteries. Look for the ‘HR’ stamp on the bottom of the battery that indicates it is a Sanyo OEM.
More batteries will be tested and added to the Battery Round-up page.
Notes: Batteries (new) were tested using a LaCrosse AlphaPower BC-900 in the ‘Refresh Mode’. I used a charge current of 500mA (about 0.5C) and a discharge current of 250mA (about 0.25C). Capacity (C) is measure by discharging the battery to an end voltage of 0.9V under constant load. Batteries were repeatedly discharged and charged until the capacity was stable. The discharge current is similar to that used by the manufacturers to spec their batteries. Sometimes, manufacturers use a lower charge current over a longer time period. IMHO, not practical for routine use. And, the results may not be indicative of the real world but help in comparing batteries.
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Im not positive but i think that a charge/discharge rate of 500/250 is much too high to get a fair reading on ~800 mah AAA batts….lacrosse 900 allows 200/100 and i bet that give better results..