Remarkable Eneloops

My first thought: sad you didn't check the capacity right from the package.. that would have been the oldest eneloop discharge test currently available....Or however I should phrase that.

But thanks a lot for sharing!!!

Well, if you tell me how to do that, I have another identical unopened pack.

(I also have two unopened 2-packs of AAA with same date).


Edit: to say I have an even better idea.

P.M. me your mailing address and I’ll send these to you - we’ll just call it my sacrifice for science. :wink: . You run whatever tests you think will gain us the most information and share it with the board.

Great idea, let ChibiM use them for some all round evaluation and testing.

The last four pieces from that 8-pack finished their break in cycle overnight, and the results (read from the charger) were:

1914 mAh

…three of them higher than the first four, with one notably lower.

I noticed one oddity that may be a function of my charger - the first four showed termination at 1.48 v , while these last four all showed 1.44 v when I fetched them off the charger. After 30 minutes all four showed 1.43 v on my DMM. I don’t know exactly how long each set remained on the charger after termination, or if the charger shows the voltage at termination, or ‘at the monent’.

(For those not familiar with the C-9000 charger, break in is a lengthy process of 40ish hours, and both sets terminated sometime during the second night.)

I wish I’d double checked the first four with the DMM after a half hour, but I didn’t.

ChibiM, if you’d like to run some more sophisticated analyses on these old cells, I have a couple of sealed packs remaining that I’d be pleased to send you at no cost.

I will PM you Tumbleweed! Appreciate it

I have Eneloop AA’s from 2008 that are still in use. They started out life in my camera flash units, taking a beating at weddings. They would come out of the flash unit too hot to hold after literally 700 or more flash photo’s. Nowadays they live an easier life in wireless Mouse units and small flashlights, but they still work fine.

AA Cycler has some very good long-duration cycle tests on Eneloops. Looks like they’re good for about 300-400 full cycles.

After that, internal resistance starts to sky-rocket very quickly. Capacity starts to drop as well, though more slowly. This is my personal anecdotal experience as well, so it’s good to see it’s backed up by real testing.

The conclusion seems to be that after a few hundred cycles, retire them to low-drain applications. If you do partial cycles, you’ll get a lot more out of them.

My personal experience is that they also start to lose their low-self-discharge ability as well, though they’ll still hold a charge for a few months. I have a few worn-out Eneloops that I still use in things like solar lawn lights.

With the advice of ChibiM, I opened another pack of eight, found that once again all eight tested exactly 1.27 v., and put the first four on ‘discharge’ mode right out of the pack.

After 150 minutes of discharge at 500 mA, the discharge stopped at 1.20 v.

Discharge readings were: 1146 mAh, 1153, 1138, and 1145.

After almost 13 years, these cells are still at roughly 60% capacity.

The last four are now being discharged in similar fashion.

Yep, Eneloops are REMARKABLE Tumbleweed48… :+1:
Thanks for sharing your ‘Eneloop Story’, it’s a great one.

My ‘Eneloop Story’, from another thread; is copied & pasted below.

Bravo! Thanks so much for the discharge test Tumbleweed48! Awesome numbers. And keep in mind that overseas cells didnt get charged 100% before shipping out but rather 70-75%.. So yeah, remarkable batteries! See how close those numbers are? Wow... any other brand would have been dead or mismatched numbers. I can't believe they were so close.

If you don't mind, I will add this info to the eneloop101 website.

The final four have completed the discharge cycle, with two terminating ar 1.20 v. and two at 1.21 v.
Capacities of these four were:

1152 mAh, 1187, 1143, 1147.

The average across eight cells is 1,151 mAh, or almost exactly 60% of the stated 1900 mAh capacity.

Maximum deviation from the average is a mere +36 / –13 mAh.

I will now start a break in cycle, and report back in a couple of days.

By all means, ChibiM, use the data as you see fit. The more we can all learn, the better! :+1:

Eneloops are Eneloops… no contest! Incredible technology indeed. :+1: :+1:

End of discharge should be 0.9 volts 1 volts ,how come you say 1.2 volts? Terminatin when charging should be 1.48v 1.5ish.

I just left them on the charger until the charger terminated and said “done”, then read the numbers and posted them.

I don’t know of any way to set a C-9000 to any different parameters. Other chargers might be different, but this is all I have.

Well the numbers look good so I don’t think it’s anything to worry about.

Robot girls .... Seemed like the perfect solution to an age old problem .

then she left me for a Subaru.

I’ve been using Eneloop and Eneloop Pro for about a year and I’ve been very happy. I’m always glad to see more confirmation of a good investment. :smiley:

Just a quick final update; the last eight cells dated June 2006 have completed their break in cycle on the Maha C-9000 charger.

Average capacity works out to 1920.2 mAh with a variance of –20 / +46 mAh.

The lowest indicated 1900 mAh, while the highest is 1966 mAh, with the rest clustered nearer the average.

On a less encouraging note, I managed to destroy a FourSevens Mini M2A trying to open it for an emitter upgrade. Oh well… :person_facepalming: …I tried!

What was that someone said about glue?

I have 8x standard AA and AAA eneloop unopened since 2013.

Also 8x unopened AAA eneloop XXsince 2017

Lets keep them unused for… 15 years and see what happens.

Eneloop powaaaa

If I’m still here in 15 years and this forum is still a thing, I look forward to seeing the results.