Saturday, 16 July 2011
Eneloop - low discharge nimh, rechargeable batteries
I have done extensive testing on the original eneloop rechargeable batteries since early 2007, shortly after they were introduced in the US. I have also tested the blue second-generation eneloop cells from the Costco eneloop package back in 2010. But this is the first time I have seen second-gen eneloop in white wrappings being sold in the US. With so much talk about counterfeit eneloop going around, I was understandably cautious when I purchased those SANYO NEW 1500 eneloop 8 Pack AA Ni-MH Pre-Charged Rechargeable Batteries.
I tested four of those cells, using my old La Crosse BC-900 Battery Charger.
- Right out of the package, their average remaining charge is 1568mAh, or nearly 80% of the rated capacity of 2000mAh. The spread is also very small, from 1558 to 1577mAh. This proves that they are indeed low-self-discharge type. (Date code on my cells says "11-01", or Jan 2011)
- After one recharge/discharge cycle, their average capacity improved to 2115mAh
- After two more recharge/discharge cycles, their average capacity leveled off at 2133mAh, or more than 6% higher than the rated capacity.
The above results are very consistent with what I have previously observed, while testing second-gen eneloop cells in the Costco package. Therefore I'm convinced that those are indeed genuine second-gen Sanyo eneloop cells. (See the scans I uploaded to Customer Images section, if you need to distinguish between old and new eneloop cells)
On the other hand, currently the prices of those new eneloop cells are about 25-50% higher than that of the original eneloop cells. So one may question: do the new eneloop cells offer sufficient improvement over the old, to justify the price different? Let's compare the following factors:
- Cycle Life: The 2nd-gen eneloop claims to "recharge up to 1500 cycles", while the original only claims 1000 cycles. This 50% improvement looks great on paper, but note that if you recharge your eneloop cells twice every week, it will take 10 years to reach 1000 cycles. So in real life, most average users will never notice the difference.
- Self-Discharge Rate: The new eneloop cells claim to "maintain 75% charge after 3 years", while the original only claims "80% after 2 years". Again, in real life most people will never notice the difference.
- Capacity: First-gen eneloop AA cells have "Typ 2000mAh, Min 1900mAh" printed on them, while 2nd-gen eneloop AA cells only say "Min 1900mAh". But in fact they have the same capacity rating of 2000mAh (typical) according to official Sanyo web site. My measured capacity numbers are actually around 2100mAh for both versions.
BOTTOM LINE:
Both the new and old eneloop cells are excellent products. You can safely mix and match them in any application, and probably nobody can tell the difference in the next 10 years. But in case you can't decide which version is a better value... Just flip a coin and pick one - you can't lose either way! SANYO NEW 1500 eneloop 8 Pack AA Ni-MH Pre-Charged Rechargeable Batteries
I put two Eneloop AA batteries into my Kodak Easyshare C182 digital camera. I took flash photos one after another, in order to drain the batteries. I counted 250 photos before the low-battery warning automatically shut off the camera. That's a pretty good number of photos from one set of batteries. I'd never have gotten anywhere near that many with alkalines. And you can recharge these Eneloops up to 1500 times, so maybe one set of Eneloop AA batteries will let me take, eventually, more than 350,000 photos. If I take 20 photos each day, then two batteries would let me take photos for about 48 years. Four would suffice for a lifetime. The camera will wear out before the batteries do. I bought 32 of them, just in case there are other things that need AA batteries, also. And I bought 28 AAA size Eneloop batteries, too.
I'm pretty sure I've reviewed these Eneloop batteries before but I use them so much and like them so much - I think they deserve another 5-star review!
I'm not sure what's NEW about these batteries, but they seem to be just as good as the previous Eneloops.
First, I've got about two dozen of these batteries in daily use. I've Never had one fail to take a charge and I'm sure I've cycled some of these well over 250 times.
I use them in remote controls, professional Nikon flash units, high powered LED flashlights (like the Fenix TK-40 which uses 8 AA cells) and many other applications.
I only charge them with this charger: Maha PowerEx MH-C808M Ultimate Professional Charger - available on Amazon. This model charges AAA, C, And D batteries as well. There is an AA-only model for a little less.
I think the charger is the key to long life. Some chargers keep charging or charge at such a high rate that they batteries overheat and fail prematurely.
Sanyo claims these batteries will hold at least 80% of their charge for a year. I actually tested this with two batteries. I brought them to a full charge and let them sit for a full year. Then I tested them with my tester (ZTS Multi Battery Tester - ZTS MBT-1). They both showed 80 percent. Most NiMh batteries would be totally dead after sitting for an entire year.
Note: if you want to test NiMh batteries accurately (along with many other battery types) get this charger available at Amazon: ZTS Multi Battery Tester - ZTS MBT-1. It's the best by far. - Low Discharge Nimh - Rechargeable Batteries'
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