So how have your Eneloops held up after prolonged use?

I have 6 Eneloops, 4 AA from 2nd gen and 2 AAA from 1st gen. All bought in June 2011.

I never used AAA's much so cant say how good have they performed and whether they have lost their capacity considerably or not.

But its different story with my AA's - Ive used them only in my digicam, once the camera says that the batteries are empty, that means that after couple of shots the camera will shut down and will not power up again, this has always been good enough indicator that fresh set of Eneloops should be put in.

Ive always discharged my Eneloops in my camera that way, sometimes even up to the point that the camera will not power up anymore.

Dont know how many charge cycles have they gone through, I also dont know what their initial capacity was when they were brand new.

Month or two ago I tested them with C9000 and all of them showed capacities somewhere in the middle between 1700 and 1800mAh's, none of them were near rated 1900mAh, no surprise there given that I expected them to be 1900mAh when brand new at best.

However, few days ago I put them in C9000 and started break-in mode(its recommended in case batteries cant be refreshed to desired levels with refresh mode with C9000) to try to revive them.

Frankly it doesnt look like it did much to them, now they are all around 1800'ish mAh's, havent re-tested them again, but so far it seems that first two break-in charges at 0.1C for 16h has given no substantial benefits.

Should I attempt to try one or two more break-in cycles with these or simply accept that they have been abused too much during 1.5 years in my digicam?

My selected capacities were 2000mAh during first 16h charge and 2100mAh during second 16h charge, somehow I expected that if during first charge it "expands" them into 2000mAh territory then with 2nd charge I could get them closer to what other users have reported and get some 2000+mAh's in/out of them :D!

I haven’t even charged my Eneloop AAs since buying them 8 months ago. lol But they’ve not been dimming in any light yet.

my eneloops are 1 year old afaik .. after the break-in i can tell you more about them. break-in takes 2 days per 4 cells. so see you in 2 weeks :D

LOL, Kreisler, you can try to do that in da ghetto style:
Charge 4 batteries for 16h at 0.1C in break-in mode, once they are done charging for first 16h pull them out and insert fresh batch of batteries, and so on.
Do this 2x per battery batch and youre done. Discharge them manually in flashlights to save time.
This way it wont take you 2 weeks.

true, but it sounds like more work. i would have to coordinate the batches and time them myself. i bought the C9000 so that it does all the work and wait not me haha

good idea anyway thanks. worth an inspiration.

I have 64 Eneloop AAs, the oldest being 28 bought in 2007. One of these cells was DOA, and was replaced by the retailer. My uses are lights, camera flashes, and portable radios. All the cells are numbered, and I run a break-in on them all roughly once a year to keep an eye on their capacity.

All the cells have shown virtually no change in capacity whatsoever yet, and measure between 1950 and 2020mAh approximately. My C9000 is one of the first batch, which gives a slightly higher result than the current models - about 6% is the is the difference I seem to remember.

Hmm, thats interesting, didge, thanks for sharing!

Kreisler - its not that much of a hassle, you have to remember to change batteries in charger between 16h and 18th hours, thats it :D!

I have not used a C9000. But I charge my new NiMH cells with a hobby charger to 1.6C. Because NiMH cells dissipate some of the charging wattage as heat, 2000mAh Duraloop wrappers say to charge at 200mA for 16 hours (3200mAh charge).

I reckon you’ll see an improvement with a refresh/break-in charge of 3040mAh (160% *1900mAh)

With nearly 100 eneloops of various flavors (1st, 2nd gen and duraloops), all in a 60-90 day rotation (AA & AAA) I have not had a single failure or noticed a lack of capacity. Several of them date back to 2009. No wonder these are known as the world’s overall best NIMH cells money can buy. I also dont let them run below about 1V before recharging.

Of all the later technology cells, the C9000 break-in mode has resulted in diminished cell capacity for me. It has only given me positive results with some very old NiCads, so I avoid that mode all together. My cells already get thoroughly cycled from normal use and I have yet to find a weak one when driven in series with many others. When that day comes, I’ll identify the weak cell and discard it.

To prevent heating during charging, I charge AA’s @ 800mA and AAA’s @ 300mA. My results are the most consistent at those charging currents, regardless of what others blabber on and on about (avoid the BS thousand comment CPF thread about the C9000). I have 2 x C9000’s and have never experienced a failed termination or incomplete charge. I also leave AA cells in the station for at least 1.5 hours after the charge completes so they get the 150mA top-off charge. AAA’s get removed soon after charging completes.

The C9000 and eneloops are an unbeatable team in these size cells, but they also represent a significant investment.

I have cycled one particular pair of cells 2 years on radio Peltor´s. Switch is broken, so they are always on.

I charge them once a week. Recently, I tested them and they were still within factory specs.

My oldest Eneloops were bought in June 2008. After seeing this thread, I tracked them down and ran a Refresh/Analyze cycle on them (1000mA charge, 500mA discharge) to see how they’ve held up. Originally they were all right around 2000 mAh, now they are about 1930 mAh. So 3.5% loss in almost 5 years. They’ve been in use most of that time, though not heavily.

with my C9000 i did triple cycles, break-ins, refresh&analyze's, and again break-ins and refresh&analyze's, stored the cells in between for 2-3 days offline or in parallel, etc etc, all in an effort to recover the highest capacity possible. i do have all the details on a sheet of paper but one would be only interested in the result or my conclusion i guess?

please see below table for a summary in form of averaged capacities:

averaged capacities

Eneloop pack











4-pack AAA

11-05 LF

844 mAh 823 mAh 782 mAh 786 mAh clear loss

4-pack AAA

11-05 LG

824 mAh 824 mAh 818 mAh 815 mAh minimal loss

8-pack AA

10-11 UQ

2011 mAh 2037 mAh 2030 mAh 2038 mAh zero loss

Note: I performed triple cycling with all packs in order to learn about the actual capacity prior to the start of the (repeated) break-ins and their subsequent refresh&analyze's. Interestingly, cycling a cell repeated times does increase the actual capacity a bit, although this observation is not a fact or 100% consistent. Cycling a cell gives you a reference point so that you know by how much the break-in improved the capacity. I didn't include the cycling details, (4+4+8)*3= 48 numbers!!, in this post yawn.

In blablah words, after 1.0yrs of moderate usage i was able to reset 100% fully the AA-sized Eneloops. Unfortunately i do notice a loss of capacity in the AAA-sized Eneloops. Maybe the AAA cells —i had bought them in bulk from an obscure Geman ebay seller— were fake or something.

From now on, i will reset the cells more often, say every 4 or 6 months, instead of 1x per year!!

Sorry to revive this thread, but I’m interested to know if the cells from 2006-2008 are still working fine.
I just bought some eneloops (and found one in the local recycling center!!) to replace my Duracell 2650mAh bought about 8 years ago.
The Duracell cells had very gentle use but have now developed a high internal resistance.
Do the eneloop still have a low resistance and high capacity?

I use Eneloop (AA) that age (early 2007). About 200 recharges (two or three times per month).
Capacity: about or over 90%. Internal resistence: ignore (when new and current).

I'm going to test some of my Duraloops. Unfortunately I didn't test them when they were new, so I can't compare, but I'll put a note in my test that says when they were purchased and manufactured.

Thank you two for the feedback!

I bought mine(2) somewhere in 2009, long before I was more informed about battery and charger choices and their maintenance so I didnt baby them, used in digicam.

They are below 1.9A, more like 1.8A+, cant say about internal resistance but I believe that they work well to this day in my digicam.

I believe that if one can afford to buy Eneloops, then one must do so, they are IMHO among the best ones.

Hi folks,

I have a skyrc mc3000 nd have just started trying to refresh a batch of 2650mha eneloops that have only ever been charged on cheapo chargers and have not been broken in.
Still learing about this stuff and I appreciate all the help here.
One of the eneloops is showing 469meg ohm internal resistance.
All other redings seem ok, and it charges up to voltage quicker than the other cells which are all around 28-35 ir.
Is this a dead cell? Can it be rejuvinated?
Cheers ed

I bought Powerex C9000 early 2011 (checked my post histtory).
I think I have been using Eneloops from that time roughly.

Not a single one has failed to date, not a single one has been out-of-specs when arrived.
I think I have bought them about 30 to myself and the same amount to others as well.

Oldest ones were at about 1,9000mAh when I measured them.
After measuring, I inserted them into dead shaver & toothbrush - which started working like never before with far longer operating time / charge than as new :slight_smile:

I have really few places, where I use alkalines anymore at all.

It is hard to think reasons at all why not to use them. In here alkalines are about 25% of Eneloops price.
Charge 5 times and youre already on plus-side :slight_smile:

AFAIK, there has never been any Eneloops with a capacity of 2650 mAh. Do you mean 2450 mAh (Eneloop Pro)? I don’t think the Pro’s stand up to abuse nearly as well as the regular Eneloops, so it wouldn’t surprise me if a cheap charger would kill them.

I’m still using regular Eneloops from 2006. They’ve lost about 10% of their capacity when discharged at 2 amps, compared to new Eneloops. Pretty damn good for 10 year old cells. I expect they’ll still be useful in another 10 years, though probably not for high-drain by that point.