We all use them; from camera flashes to television remotes, AA batteries find their way into every home. But just like other energy sources, batteries can be very costly as well. With a wide range of prices from store to store, a bit of comparison shopping may be necessary to find a good deal. Need a 4-pack of alkaline batteries at a tourist trap? Forget about it -- that'll be 10 dollars please.
With plenty of time to plan ahead, we shopped around for the best prices, dropping two Franklins at Wal-Mart. $200 bought seven sets of rechargeable and seven sets of single-use batteries -- 84 batteries in total. With individual single-use batteries ranging in price from 50-cents to upwards of four dollars (purchased in packs of four or eight), our objective was simple: Calculate cost per shot for each battery.
Each set of batteries was put through a series of three tests. Batteries were tested twice using the 8-megapixel Canon PowerShot SX100IS, once with and once without using the built-in flash. The camera was tethered to a computer and fired using Canon's Remote Capture software, with each and every setting carefully matched before each test to ensure consistency. The camera continued firing until each pair of batteries was depleted, with shot intervals of five seconds for the flash off test and 15 seconds while the flash was on. This portion of the battery test often ran overnight.
In case you're interested in the technical details -- images were captured at full resolution and sent directly to the computer for storage. The camera fired at ISO 400, f/2.8, 1/20 sec. for the flash off test and ISO 100, f/4, 1/160 sec. with the flash on. Focus was locked for both tests and the autofocus assist lamp was turned off. Because the camera did not focus and images were not displayed on screen between shots, the number of shots captured with each battery is significantly higher than you may experience with daily use. Nonetheless, this technique proved accurate for comparing life between different types of batteries.
Please continue on to Page 2 for results from our rechargeable and single-use battery tests.