Long term 2nd and 1st generation Eneloop observations!

I bought my first 4-pack of 2nd generation Eneloops and their 2 slot “quick” charger combo with two first generation AAA Eneloops back in 2010 when I had no knowledge about batteries, chargers and proper care for both.
Reason - digital camera that took AA’s instead of custom lithium battery.

Given that it was my first experience with Eneloops I never really broke them in as required with new NiMh rechargeables.

AAA got barely used, wrapper on one of them pretty soon slided slightly to the top of the positive end of the battery, leaving some 1mm unwrapped at the bottom sides of the battery.

I tested their capacity yesterday after charge-discharge and they were somewhere slightly below 700mAh, somewhere around 660-670.

So, aside from no proper conditioning and one slippery wrapper, I guess they were good, being unused for the most of the time. I wonder why the wrapper slidded to the top so easily, given there was no force or lubricants applied to it?

Now, with AA Eneloops its a bit different story, they too, were never conditioned, neither abused, however, digital camera, that I used them in, was quite demanding, as in, it took 2 batteries at once and I usually used them until the battery level was too low and the camera shut down. Not that I abused that camera and shot all day and night long with flash or 720p videos, so it wasnt used all that frequent.
Still, batteries got kind of visually worn out with this camera, their positive ends have dot marks from cameras internals, the same goes for negative ends, the plate on some of them even looks slightly bent inwards!
Perhaps from some occasional use in recent years in some lights? Very little use such way(ie, in lights that is)!

I dropped some of them couple of times on the ground accidentally, but that should not have contributed to their somewhat low capacity today, which is around 1770-1820 for three of them and less than 1700 for the fourth one when discharging at both 1A and 0.5A. Further discharge at 0.1 yielded little bit more, putting the paltry <1700mAh battery around 1720mAh, while the others close to or exceeding 1800mAh.

I remember Kreisler-squirrel saying that his old and frequently used Eneloops had above 2000mAh when new and still had above 1900mAh when re-freshed, if Im nost mistaken.

Since I had only 4xAA Eneloops and 2xAAA ones(of which I had very little to no use of at all, since I dont have any AAA gadgets at home except for Thrunite Ti) they were never used as my main flashlight batteries thus my Turnigy’s had the honour!

Now that I have started to upgrade my AA stock with latest Eneloops, I decided to take the old ones and see if they could be brought back to a new life, thus the speculation about their capacity, life cycle and future usability.

Will update this thread after I do initial discharge and charge of the fresh ones these days.

Thanks for reading and will appreciate your thoughts and stories about your Eneloops, nevermind the generation or usage patterns :)!

Little remark regarding 8 of the regular Eneloops that I bought for someone else, I didnt bother with break-in cycle with C9000 given how much time it would consume(3 days non-stop charging for all 8 ), so I just did multiple discharge-charge cycles, I think 2 or 3, all at pretty tender charging and discharging currents and got less than 1900mAh on all of them, so it looks like they will need either two break-in cycles on C9000 or few more discharge-charge cycles.

Recently found a packet of unopened first generation HR-3UTG date code April 2006. 2 Cells inside so discharged each at 0.2C to 1.0V. Results 72% & 73% of capacity after 9 years. Impressive!

I'll be interested to see what a proper break-in cycle or 2 with the C9000 will show. Keep in mind that the original specs for the Eneloops said 1900 minimum, so not sure about Kriesler's results. Don't forget that the C9000 supposedly needs another 2 hours after "done" to top them off fully so this may have affected your discharge readings.

I expect your camera would not drive one cell into reversal (if you run it to extinction) but other things like lights might. A couple of reversals might explain one cell weaker than the others but retaining around 1800 seems pretty good for a 5 year old battery without forming cycles.

I have some older 2300 LSD Imedion AAs that seem to be suffering more from the wrapping self-destructing. My Eneloops are holding up better.

I first bought a set of Eneloops in 2006 for Mum's Canon digital camera (takes 4). She doesn't use it heavily but they are now nearly 10 years old. Probably less than 5 cycles per year. She mostly uses the "dumb" timer-based Sanyo charger they were supplied with. I ran a refresh/forming cycle for her with my C9000 last year and all returned over 1800 mAh.

After years of using NiMH of various dodgy pedigrees the Eneloops were a revolution for me. The second revolution was investing in the C9000 and finding out just how bad some of my previous rechargeables were!


Eneloop is da best!

Well, the Japanese cells are anyway…

Out of dummy's curiosity...what is "a proper break-in procedure"? I honestly don't know :)

Super long charge at 0,1C, with 0,2 and 0,25mA charge rate for AA Eneloop and Eneloop Pro respectively, then discharge and charge again, so called forming of the battery, on MAHA C9000 known as break-in mode, takes 1,5 days to complete on 4 batt’s.

Just did 0,1A discharge on 1 regular and 1 Pro, reg shows 1422mAh(mfg date 14-06) and Pro shows 1379mAh(mfg date 14-12).

3 more regulars being discharged atm, 15 Pro’s awaiting their turn, probably starting next week’s end when I combine the power of two C9000 :D!
Will do full discharge and break in on all 16 then, probably will do the same with regular ones this weekend, seems that breaking in might not be a myth as some claim ;)!

I’ve never heard of this, does Panasonic recommend we do this?

Not sure, what I know is that they recommend charging their batteries at 1C, which would be 2A and 2.4A respectively for regular and Pro AA Eneloops.

Heres the data after initial discharge of 4th gen white Eneloops, all but one at 0.1A, one at 0.5A:

Pretty good!

And heres one for Pro version, 3 out of 4 discharged at 0.1A, one at 0.5A:

Next 4 Pro’s at 1A discharge rate:

3rd batch discharged with Sunopux SPX-936D at 0.55mA:

Last batch discharged at 1A:

Pro’s look good too, however, these are of newer mfg date(december 2014 vs june 2014 on white ones) and of higher capacity, I dont know how much were they filled before leaving factory though, I expected them to come with higher remaining capacity than regular Eneloops :D!

Took a bit longer, after break in cycle:

Eneloop 4th gen:


Eneloop PRO:



9 - 2557

13 - 2568
14 - 2562
15 - 2516
16 - 2525

Looks like with Pro MAHA C9000 goes easier on ports 3 and 4, given that all but one(#7) battery shows “considerably” lower capacity when broken-in in these two ports.

Other than that, regular and PRO looks to be meeting its capacity claims :D!

Thanks for the update!