HolidayBuyer's Guide

AA battery roundup 2010, now with more Apple batteries

We pit the Apple rechargeable batteries against Duracell and Energizer.

Normally these batteries are at each other's throats, but I convinced them to agree to a truce in order to take their picture.Photo by Eric Franklin/CNET

Editors' note: Thanks to a calculation error, the cost per minute of life for the Apple batteries had to be adjusted down to 8.25 cents after this story was posted. I apologize for any confusion this may have caused.

Last year I posted a roundup of alkaline AA batteries and showed how they compared with each other in terms of battery life. The testing methodology I used last year, although only slightly complex, was very easy to implement. By turning on three identical flashlights, I drained two AA batteries from each of the three brands while recording the whole process with a Webcam.

I then went back to the recorded video and pinpointed the time each flashlight died. Wash, rinse, and repeat two more times and there were my results. Like I said, easy.

Easy, but perhaps not as satisfying as I'd hoped. A few users, thoughtful enough to comment, suggested some alternative tests. One of which was to use a point-and-shoot camera, set it to record video, and drain the batteries. Then check the video length of the recorded video to yield the battery life duration. So simple! This would even be easier and simpler than the flashlight tests.

One huge problem with that method, which we'll get to later.

First, I contacted the folks at Canon, and they were more than willing to participate in my mad schemes. They sent their PowerShot SX130 IS camera. I had grand plans of inserting the batteries, hitting the record button, and coming back an hour or two later to find results, a golden egg, and possibly other imaginary treats. Here's where that aforementioned problem cropped up.

As many of you no doubt know, small digital cameras like this don't record video for more than 10 minutes before automatically shutting off. A dilemma for sure, and I'd love to regale you with a triumphant tale of how I immediately came up with an elegant solution. A win-win, not only for my time, but my sanity as well.

No. I guess I'm just not that creative. Instead, I rolled up the proverbial sleeves and took the pragmatic approach. I set a timer on my iPhone to 9 minutes and started it at the same time that I pressed record on the camera. After 9 minutes, my phone alarm would go off, reminding me to stop recording and almost immediately start recording again (usually within about 2 seconds). I then made note of the exact time I stopped recording and carried on ad nauseam.

And by "ad nauseam," I mean up to three times for each brand, using a different pair of batteries each time.

Sure, I now have a Pavlovian response to hearing my phone's alarm where I raise it above my head in preparation to smash it to the ground into (hopefully) a billion pieces, but it worked.

So that's the methodology. It's not nearly perfect, but it addresses some of the concerns from last year, in particular using a high-drain device and rechargeable batteries. My hope is that the results will give you at least some idea as to the potential life of the batteries featured.

Also, please note that although we used Duracell recharged batteries, we didn't test whether any of the brands discharged while sitting around. Hopefully next time we can actually plan for that.

The "cost per minute of life" (the price you pay for each minute of charge) was based on Amazon.com's current pricing.

Brand Battery life Cost per minute of life
Apple Rechargeable 1.95 hours 8.25 cents
Duracell Rechargeable Pre-Charged 1.88 hours 4.32 cents
Energizer Recharge 2.55 hours 3.8 cents
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