By Betsy Finn, CPP
Sanyo’s Eneloop batteries are a new twist on the traditional rechargeable battery; they can retain 85 percent of their capacity over a year’s time. Because of this unique characteristic, Sanyo is able to package Eneloop batteries so they’re ready to use when you need them. The question is: Does this convenience factor come at a cost in performance? Can professional photographers really rely on a battery that is only rated at 2,000 mAH (compared to the more typical 2650 mAh or 2900 mAh)?
I was curious to see how Eneloop batteries compared to standard Ni-MH rechargeable batteries. To compare their performance, I used three Nikon Speedlights with four batteries each, set on manual flash power (one as the on-camera master, the other two as remotes). One of the remote Speedlights would be powered by Eneloop batteries, the other by standard Ni-MH batteries. After doing some research online, I discovered that my Nikon SB-800 Speedlights, at full manual power, should have a recycle time of four seconds when using Ni-MH batteries, and allow for 150 shots to be fired (Source: KenRockwell.com). With that in mind as a guideline, I set out to test the 150-shot theory and see how the Eneloop batteries compared to the standard Ni-MH batteries.
Image ©Betsy Finn
Interestingly, the Eneloop batteries actually outperformed the standard batteries until the 137th flash. Both sets of batteries then recycled within milliseconds of each other through the 200th flash. After that, the capacity of both batteries began to degrade rather quickly. At the 212th flash, the Eneloop batteries finally fell behind the standard Ni-MH batteries in recycle time, but at this point, neither Speedlight had enough capacity left to practically fire the flash (21+ seconds to recycle). After the 213th flash, the Eneloop batteries could not fire the unit at all. Over the first 150 flashes, average Eneloop recycle time was 4.65 seconds (compare to the standard Ni-MH of 5.03 seconds).
What’s my verdict? While there is certainly a trade-off between convenience and performance, using Eneloop batteries will be a viable option for some photographers. I can see using Eneloop batteries in place of standard Ni-MH batteries if you are comfortable with recycle times of around 4.65 seconds (fewer, if you add the fifth battery accessory or use an AA-powered battery pack).
A four-pack of Eneloop batteries retails for $14.92, and can be found through various retailers including Amazon.com. For a more detailed analysis of my test runs, including data and graphs, see "Are Eneloop Batteries Too Good to be True? Nope!"