Top positive review
5.0 out of 5 starsResults of capacity testing shows its slightly below the competition.
October 22, 2018
I tested the AA size Amazon brand battery to find out the actual usable capacity as compared to the AA Duracell Procell battery. The results showed that the Amazon battery is about 88 percent the capacity of the Duracell. If you calculate the cost per unit capacity, the batteries are almost identical. The Amazon battery was actually slightly more expensive when represented in cost per Watt-Hour. Because of this I would probably choose the Procell (if I can get a good price on it) just because it means less frequent battery changes. The Amazon battery is a surprisingly good battery though. You will probably barely notice the difference in capacity, so if you don't want to waste time shopping around then its a good choice.
I also performed the same test on Duracell Copper Top, and Energizer Max. Their performance was nearly identical to the Procell. More interestingly, I tested the Energizer Ultimate Lithium AA cell. This cell was 4 times the cost of a procell at $1.27 per cell! However the capacity was only 1.5 times that of the Procell. So don't waste your money on these batteries, they're much more expensive per unit of capacity. The capacity of all these batteries were measured in Watt-Hours. Here are the numbers.
AA Amazon Battery = 2.71 Wh. My cost per cell = $0.291. Cost per Watt-Hour = $0.107
AA Duracell Procell = 3.09 Wh. My cost per cell = $0.321. Cost per Watt-Hour = $0.104
AA Energizer Lithium = 4.86 Wh. My cost per cell = $1.27. Cost per Watt-Hour = $0.261
This test was done using an op-amp circuit to maintain a constant current load at 100ma. Voltage and current were being logged ounce per minute and this data was used to calculate the Amp-Hour with a 0.8 volt cutoff. The Watt-Hour was then calculated by multiplying the Amp-Hour by the average voltage from the beginning of the test to 0.8 volts. All batteries mentioned were tested using this same method. Note that the capacity of these batteries can change dramatically under different conditions. The same battery under a heavy load will have a fraction of the capacity that it would under a light load. This data is only good for a comparison when choosing what battery is worth buying at what price. Unless your device loads the battery at a constant current of 100ma.
In summery, the Amazon batteries are not bad batteries (at least based on this test using the AA cell). If you choose to shop around for a name brand battery, stay at or below $0.33 per cell. Anything above $0.33 per cell will be more expensive per unit capacity than the Amazon battery. Oh, and definitely stay away from the Energizer Lithium unless expense is not an issue. These batteries are only worth the additional cost if your application requires a light weight and relatively high capacity battery regardless of cost. These batteries are surprisingly light weight compared to an alkaline.lkaline.
