Great Battery Shootout Updated!|
(Saturday, March 2, 2002 - 13:54 EST)
Dave goes back for a second look at battery performance after a bug creeps into the system...
Well, this is a little embarassing: For all my self-inflated erudition and apparent anal-retentiveness in my "Great Battery Shootout" article, a systematic error crept in, thanks to a failing contact in the breadboard socket I used to assemble the test system with. An increasing (and variable) resistance in the circuit between the load resistors and the batteries led to a loss of calibration over time. The result was that recently-tested batteries (like the Rayovac 1600s) tested better than cells tested earlier. Argh!
I discovered this about a week before PMA, just as I was in the midst of the camera-reviewing frenzy caused by the near-simultaneous arrival of the 5 Sony digicams, Nikon 2500, and Canon D60 reviewed just prior to the show. I fixed the jig by soldering all high-current connections apart from those between the batteries and battery holder, and clamped the latter to reduce contact resistance. The result was much more repeatable results, and somewhat higher measured power capacities than previously.
The new "winners" are the Powerex 1800 mAh cells (just arrived as I was retesting the others - the Powerex 1700s would have been the winners amongst the units tested previously), although I still have more test cycles to run before I'd consider the results to be anything near definitive. I've retested all the formerly top-performing batteries, and added results for the Powerex 1800s and Sanyo 1600s I received a while back from the folks at RipVan100. (The Sanyos are now the best-performing 1600 mAh cells I've seen.)
I have a mess of retesting to do, as well as a number of new cells to test, including Panasonic 1600s, Energizer 1700s, Nexcell 1800s, and Sony 1750s. Stay tuned for another update in a couple of weeks as I work my way through more of the retests and new cells. In the meantime, check the battery shootout article for all the latest.