From NLee the engineer on amazon,
[Q1] Why are there so many eneloop batteries with different capacity ratings and cycle-life numbers?
[A] There are actually three families of eneloop batteries:
- Standard version: The original Sanyo eneloop (circa 2006) was rated for capacity of 2000mAh typical for AA (800mAh for AAA) and 1000-cycle lifespan. Subsequent generations advertise longer lifespan (1500/1800/2100-cycles) at the same capacity. The charge retention rates have steadily extended from "85% after 1 year" to "90% after 1 year; 70% after 5 years"
(Refer to my uploaded photo on how to identify different generations of eneloop cells)
- High-Capacity version: The original Sanyo XX (circa 2010) was rated for 2500mAh but only 500 cycles. The charge-retention rate is slightly poorer at "75% after 1 year". Newer Panasonic eneloop PRO bumped the capacity to 2550mAh and charge-retention rate to "85% after 1 year".
- LITE version: Those have half the capacity of standard eneloop but twice the cycle life. They are not marketed in the US.
[Q2] Do I get better performance from the latest generation Panasonic eneloop cells verses earlier generation Sanyo eneloop cells?
[A] On paper, newer generation offers longer cycle life and lower self-discharge rate. In practice, however, youll see no difference since they all have the same capacity. The difference in charge retention rate and cycle life may become noticeable after ~10 year, if at all.
Also, about the amazon cells,
[Q6] What about the AmazonBasics Pre-Charged Rechargeable Batteries?
[A] To clarify, there are three different versions of AmazonBasic rechargeable NiMH batteries:
- The original AmazonBasics AA NiMH Pre-Charged Rechargeable Batteries came in black wrappers. They are made in China and have the capacity rating of 2000mAh. They are NOT as good as Sanyo eneloop batteries.
- The second version of AmazonBasics Pre-Charged Rechargeable Batteries came in white wrappers. They are made in Japan and also have the capacity rating of 2000mAh. They appear to be rebranded 2nd-gen eneloop.
- The third version is also black but called AmazonBasics High-Capacity Pre-Charged Rechargeable Batteries. They appear to be rebranded eneloop PRO. They are rated 2400mAh, but actual capacity is around 2550mAh.