Battery Round-up

Brand and Nominal Capacity (AA)		Measured Capacity (mAh)	%RSD	Measured Capacity (%)	End Voltage (V)	Rating
Eneloop	2000	2,105	1	105.3	1.30
Imedion	2100	2,208	1	105.1	1.46
Konnoc	2500	2,430	2	97.2	1.45
Powerex	2500	2,330	4	93.4	1.42
Powerex	2700	2,698	2	99.9	1.45
Sanyo	2500	2,498	1	99.9	1.44
Sanyo	2700	2,654	3	96.6	1.46
Varta	2700	2,670	1	98.9	1.45

Brand and Nominal Capacity (AAA)		Measured Capacity (mAh)	%RSD	Measured Capacity (%)	End Voltage (V)	Rating
3YD	750	719	3	95.9	1.46
Eneloop	800	800	1	100	1.49
Konnoc	900	698	4	77.6	1.45
Moden	1000	789	4	78.9	1.45
Powerex	900	830	1	93.3	1.45
Powerex	1000	960	1	96.0	1.47
Sanyo	900	873	1	97.0	1.45
Sanyo	1000	930	1	93.0	1.46
Varta	800	703	1	87.9	1.44

Notes:

1) Batteries were tested using a La Crosse AlphaPower BC-900 in the ‘Refresh Mode’. For AA batteries, a discharge current of 500mA was set which results in a charge current of 1000mA. For AAA batteries, a discharge current of 250mA was set which results in a charge current of 500mA. Batteries were repeatedly discharged and charged until the capacity was stable. For a 2500mAh set of AA batteries one discharge/charge cycle takes about 7.5 hours (5 hours discharging and 2.5 hours charging). Room temperature was about 25 degrees centigrade.

2) Minimum discharge/charge currents settable with the BC-900 are 100mA/200mA. These settings result in optimum battery life due to low heat produced but are not practical for routine testing as one discharge/charge cycle takes about 38 hours for a set of 2500mAh batteries. The entire refresh cycle could take as long as a week. In addition, the more aggressive discharge/charge currents of 500mA/1000mA are closer to what the battery manufacturers are using to spec their batteries.

3) The BC-900 default charge current (Charge Mode) is 200mA. However, at that current it takes 12+ hours to charge a set of new 2500mAh batteries — just too slow for me. I recommend using 500mA for routine charging. At 500mA, charging takes about ~5 hours and generates minimal heat. Once the batteries are charged, the AlphaPower automatically applies a trickle charge current so you can leave a set in the charger ready for quick use.

4) Where are the other major brands? Most Sony, Energizer, and Kodak rechargeable NiMH batteries are re-labeled Sanyo batteries (Sanyo OEM). You can confirm this by looking for the small ‘HR’ stamped on the bottom of the battery.

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