Low Self-Discharge AA Battery Test Results

  Duracell(5)
Rechargeable
Pre-charged		 E8GE 1000
Ready to Use
Rechargeable		 EasyPix
Pre-charged
Rechargeable		 Panasonic
R2 Technology
Rechargeable		 Powerex
Imedion		 President's
Choice
Rechargeable		 Rayovac
Hybrid		 Sanyo(4)
Eneloop		 Sony
CycleEnergy
Made in... Japan China China China Taiwan Japan China Japan Japan
Fresh Out of the Package(1)
Capacity(2)
(mAh)		 1383 1708 1443 682 1573 1387 1489 1439 1377
Energy
(mWh)		 1509 1818 1565 719 1697 1502 1557 1588 1500
Voltage(3)
(V)		 1.09 1.06 1.08 1.05 1.08 1.08 1.05 1.10 1.09
Immediately after Recharging
Capacity
(mAh)		 1888 1967 2019 1781 2014 1871 1962 1928 1874
Energy
(mWh)		 2181 2183 2268 2037 2240 2131 2216 2217 2167
Voltage
(V)		 1.15 1.11 1.12 1.14 1.11 1.14 1.13 1.15 1.16
One Week after Recharging
Capacity
(mAh)		 1770 1807 1880 1667 1881 1771 1772 1796 1757
Retention
(%)		 93.8 91.8 93.1 93.6 93.4 94.7 90.3 93.2 93.8
Energy
(mWh)		 1946 1973 2071 1795 2056 1949 1905 1979 1964
Voltage
(V)		 1.10 1.09 1.10 1.08 1.09 1.10 1.08 1.10 1.12
Seven Weeks after Recharging
Capacity
(mAh)		 1729 1714 1780 1581 1803 1718 1677 1763 1711
Retention
(%)		 91.6 87.1 88.2 88.8 89.5 91.8 85.5 91.4 91.3
Energy
(mWh)		 1871 1846 1922 1686 1931 1891 1780 1943 1876
Voltage
(V)		 1.08 1.08 1.08 1.07 1.07 1.10 1.06 1.10 1.10

Notes

  1. Out-of-the-box capacity is provided for interest's sake only. It is not a very useful measure because it really depends on how long the batteries sat on the shelf before you bought them, and the conditions under which they were shipped and stored.
  2. The capacity was measured at a 1200mA discharge rate, which is about three times the current at which the manufacturers measure the capacity. As a result, all of these batteries test lower than the advertised capacity. However, the results are more realistic for high-current applications like digital cameras.
  3. This is the average voltage that the battery provided during a full discharge at 1200mA. This is not the same voltage you would see if you just measured it with a multimeter, but it is typical of the instantaneous voltage a digital camera might see while snapping a picture.
  4. The results reported in this chart for Sanyo's Eneloop batteries are not identical to those in my original 2007 Eneloop review because I have tested a new set for this comparison, using the same new BattMan II battery analyzer that all the other brands were tested with. The differences are due to the normal variation among batteries of the same brand, and differences in the equipment used.
  5. The Duracell Rechargeable Pre-charged batteries that I tested were the ones with a white ring around the positive terminal. Since then, Duracell has switched to batteries made in China. These can be distinguished by a black ring around the positive terminal. I have not tested those, but reports from others suggest that their performance is more like that of the Rayovac Hybrid batteries.

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