should i buy Sanyo NEW 1500 eneloop 2-AA Ni-MH Pre-Charged reviews

The new SEC-NCSC2AAN eneloop "C" spacer kit with 2 AA batteries utilizes SANYO's advanced rechargeable battery technology allowing them to last longer than ever before! They provide excellent performance-to-cost advantages over both conventional alkaline and other rechargeable batteries. Unlike disposable batteries which can only be used only once and are wasteful to the environment, the new eneloop batteries can be recharged up to 1,500 times. They come pre-charged, can be used immediately out of the pack and maintain 75% of their charge for up to 3 years when not in use. Eneloop batteries deliver reliable battery performance when you need it the most! I have done extensive testing on thesince early 2007, shortly after they were introduced in the US. I have also tested the blue second-generation eneloop cells from the 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
I tested four of those cells, using my old
- 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!

[Update on July 31, 2011]
Long term self-discharge data: I have tested a pair of new eneloop AA cells after 104 days sitting on the shelf (the batteries, not me). The average remaining charge is 88.7%. This charge-retention rate is slightly better than that of the original eneloop, but the difference is within margin of error for my experiment.

[Update on May 8, 2012]
Nowadays the 2nd-gen eneloop cells are generally priced lower than the original. So you should definitely get the newer version.

Just in case you are looking for my "Sanyo eneloop FAQ", it can now be found here:
http://www.amazon.com/review/R9VPVQ0UO2MKH This packagecontains four second-generation eneloop AAA rechargeable batteries. I have tested those cells using my old  Here are my findings:
- Right out of the package, the average remaining charge is 640mAh, or 80% of the rated capacity (800mAh)
- After the first recharge cycle, the average capacity increased to 839mAh.
- After two more recharge/discharge cycles, the average capacity leveled off at 843mAh, or 5% higher than rated capacity.

The above is very consistent with the results I obtained last year, while testing 2nd-gen eneloop AAA cells from the Therefore I have no doubt that those batteries are genuine. Date code embossed on them says "10-12", which means Dec 2010 (see my upload in the "Customer Images" section, if you need to know where to find the date code).

According to Sanyo press releases, those 2nd-generation eneloop cells offer several benefits over the
- Can be recharged "up to 1500 cycles" (vs. "1000 cycles" for the original)
- Can hold "75% charge after 3 years" (vs. "80% after 2 years")
- Works down to -20 degree C (vs. -10 degree C)

In real life, however, it is nearly impossible for the average user to experience those benefits. Note the even if you recharge your cells twice every week, it will take nearly ten years to reach 1000 cycles. Furthermore, the advertised self-discharge rates for new and old eneloop cells are actually the same during first two years.

As to the capacity: original eneloop AAA cells have "Typ. 800mAh, Min. 750mAh" printed on them. The new eneloop AAA cells only say "Min. 750mAh". This has created confusions for some people, who thought the new version has lower capacity. But according to Sanyo web site, capacity of the new AAA is also 800mAh typical. My own test results, however, have shown that measured capacity of the original eneloop is around 4% higher than rated, whereas capacity of the new eneloop is about 5% higher than rated. Again, the difference is so small that most users will never notice it.

BOTTOM LINE:
Second-generation eneloop cells do offer some improvements over the original, but the actual benefit is very hard to verify in real life. In my case, the price I paid for this new eneloop AAA package is only 10% higher than that of the old one, so I consider it a good deal. If the price difference is much greater, then you have to decide whether it is worthwhile to pay extra for those perceived benefits.

[Update on May 31, 2011]
Prices for the new eneloop AAA have came down further during the past month, so now it is an even better deal. But just in case you are looking for greater bargains, you may want to consider the . They are priced lower than Sanyo eneloop, and have slightly higher capacity (rated 850mAh, measured 880mAh).

[Update on July 31, 2011]
Long term self-discharge data: I have tested a pair of new eneloop AAA cells after 92 days sitting on the shelf (the batteries, not me). The average remaining charge is 89.4%. This charge-retention rate is slightly better than that of the original eneloop, but the difference is within margin of error for my experiment.

[Update on July 3, 2012]
Amazon again combined multiple Sanyo eneloop products (many AA/AAA packages and different chargers) into a single product page. This makes it very difficult for people to find reviews for a specific product. In particular, my "Sanyo eneloop FAQ" was previously attached to the product page of but now it can only be found by following this link:
http://www.amazon.com/review/R9VPVQ0UO2MKH