Bests & Worsts Reviews from Amazon

This package (Sanyo SEC-HR4U4BPN) contains four second-generation eneloop AAA rechargeable batteries. I have tested those cells using my old La Crosse BC-900 Advanced Battery Charger. 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 Costco package. 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 original eneloop: - 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 GP ReCkyo Pre-Charged AAA cells. 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 Sanyo eneloop 4 Pack AA, but now it can only be found by following this link: http://www.amazon.com/review/R9VPVQ0UO2MKH