eneloop longevity

[Shadowww]

Minor point, but I think the second charge of BIM is also 16 hours. The whole process of a Maha BIM takes something like 39 hours.

Oops, indeed - my bad!

 

[hopkins]

Eneloop longevity rules. Last winter I placed 2 of them inside D-cell adapter sleeves to power one of those Harbor Freight electronic bug zappers
(looks like a tennis racket) to go after a big spider on the ceiling. Now 5 months later I needed to rid the patio of some wood wasps and thought to dig
the zapper out of a forgotten drawer. Bingo! The charge was still good and did the wasps in. One touch and they fall to the ground dead.

 

[Trevtrain]

...and another resurrection here in 2012. Worthy of it, since the thread documents historical Eneloop performance. I've been using the BI mode on my Maha C9000 to revive my cells and have observed:

2006-vintage Eneloop AAs average 1871 mAh capacity (for 12 cells)
2007-vintage .................................1942 mAh (for 2 cells)
2010-vintage .................................1986 mAh (for 9 cells)
2011-vintage .................................1954 mAh (for 4 cells).

None of these cells stored in refrigerator, and many of them were not sufficiently exercised (I had no Maha to refresh) until now. Many of them were in low-draw applications that would take years to deplete; some were in high-draw flashlights, and many others waiting around in the drawer to be used. So a mix of usages. Without regular R&A or BIM, these cells were not particularly well cared for.

Hi Bolster :wave:

Not to be picky here but what would be interesting to know (even despite the small sample size) is not just the average capacity but whether there was much variation between cells. Did you keep the actual figures on each cell by chance? I would consider this info arguably even more important than the average figures though perhaps negated a little by the varying usage applications they've had.

It certainly seems that Eneloops are getting some good history behind them (nearly 6 years now), though I've only had mine for about two.

Cheers

 

[Bolster]

Not to be picky here but what would be interesting to know (even despite the small sample size) is not just the average capacity but whether there was much variation between cells.

Excellent point, why didn't I think of that?

Standard deviation for:
2006 Eneloops ....................... 89 mAh
2007 Eneloops (sample size of 2 too small)
2010 Eneloops ....................... 19 mAh
2011 Eneloops ....................... 16 mAh

So, from 2006, my best is cranking out 1972 mAh, and my worst, 1645. (1500 is my unofficial "toss" number.) Sadly, I have no idea how these two cells were treated differently. Perhaps one had regular exercise and the other has been sitting. I've only recently come to the gospel of labeling cells and doing bi-annual maintenance. And I'm still not at the level of zealotry I'm recording which cells get assigned to what duties. But certainly there must be someone here who has that depth of interest.

For the record, if I drop my worst two cells from 2006, the SD = 45.

 

[apagogeas]

Is this the first evidence that eneloops do suffer after all? Probably a tortured cell, after "only" 6 years managed the worst 1645... That makes me think a 10 year useful life is easily achievable, especially considering the other cell don't show any signs of degradation. Now I try to think of any other battery I have used that long in the past and I can't think of any. Eneloops must be declared the king battery of the decade for sure!

 

[czAtlantis]

I just bought new packages of eneloops. First package was manufactured 01/2012 and second one 12/2010 (old stock :mecry. Let's say the second one was 01/2011.
Initial capacities from Maha at 500mA discharge
01/2012: 1275, 1276, 1277, 1271mAh.
12/2010: 1379, 1376, 1376, 1375mAh.
Assuming they were manufactured the same way and charged to the same level they have ~100mAh difference...this pretty good for one year storage.

 

[Wrend]

Standard capacity test would be closer to 400mA. If they've been sitting for long enough their internal resistance/impedance probably has gone up a bit. Cycling them a few times or doing the break in on them after discharging should help with that.

When I get mine, I actually do a 100mA discharge first, then the break in at 1900mAh to measure their capacity potential.

Even being older stock, they'll likely have a similarly long and useful life when compared to newer stock.

Oh, and it looks like you swapped the dates by mistake.

 

[czAtlantis]

Yeah, I swapped them, sorry
After break-in those older ones have standard capacity around 1980mAh so everything looks OK

 

[Bolster]

I actually do a 100mA discharge first,

You're a patient man! Why so slow? Does it help?

 

[Wrend]

I have 2 C9000s to help with the workload, but these days I have enough extra sets charged and ready to use. I only buy more now if I get down to only one extra set. I'm never really waiting for anything to charge any more, or whatnot.

I discharge at a slower rate before the break in because it might be a little easier on cells with higher internal resistance and more importantly that it likely helps to cycle the cells more, discharging them deeper than they would be at a faster rate, helping to refresh their performance potentials perhaps just a little more.

 

[mousewizard]

3 weeks? try 3 months. I plan to do discharge>break-in>discharge>break-in on each set to bring them to full capacity. 4days/setx25 =100days now I can cut that in half if I can get my hands on another c9000 :naughty:

That's why I have 11 of them...

 

[apagogeas]

With a bit of planning ahead, one MC-9000 is enough for all the tasks. I have about 20AA and a few more AAA, half are drained in about 2-3 weeks usage. The rest are in remotes which can easily wait months to be charged. I make a habit to estimate how much time needed for a battery to be completely drained and I schedule a recharge at half of that time, so e.g. if my wireless mouse eats up the batteries in 1 month, these batteries will be charged around every 2 weeks, so not to run out of power if a delay occurs. Any regular charging is usually performed at the weekend, the rest of the days are reserved for lengthy tasks such as break-ins or testing. There are times my maha works for a full week. Now if I have needs to charge an application more often than 2 days, I have always a set of spare LSD to keep going. I don't know what would be the case if I had 40-50AA but I think one charger wouldn't be enough really! 11 maha chargers??? That needs a dedicated desk to put them on! Can you post a photo of these together??

 

[Bolster]

IIRC, Mouse is set up to run a battery reconditioning business.

 

[mousewizard]

I don't know what would be the case if I had 40-50AA but I think one charger wouldn't be enough really! 11 maha chargers??? That needs a dedicated desk to put them on! Can you post a photo of these together??

Sure. I had to unpack everything and set up a demo display because I'm done with my Solstice charging cycle. I top off my LSD batteries on each Solstice and top off the hi-cap batteries every 90 days. Between those times the gear is stored in faraday cages. But I understand the need to see. I'm a newbie to the forum and might be full of shite.

Anyhoo... here's the setup in its full glory. In reality I only run 8 chargers at a time and three are kept as backups. All are run off DC from my solar rig, hence the DC distribution bus and customized power cables. I only put one battery in each charger because that's about what I had lying around on the bench. The rest are in storage. No; you can't see my storage.

 

[czAtlantis]

Wow, why you need so many chargers anyway?

Btw - have you tried if those Maha chargers charge exactly the same at different input voltages? I mean if results (reported capacity from same cell) at 11V and 14V are identical.
And also if results are affected by number of cells in charger - I mean if you charge/discharge one single cell in charger and when the charger is charging/discharging full 4 cells.
Thanks

 

[mousewizard]

I'm a survivalist. One of my post-collapse businesses will be bartering and charging AA/AAA batteries. So I have a stockpile of AAs and AAAs that need to be consistently refreshed. Post-collapse I'll need those chargers because part of the business model is people bringing me batteries to charge or to trade and I need to be able to cover all the bases as well as satisfy a non-trivial demand level. So I have solar panels and big batteries and inverters and hobby chargers and of course these.

No, I haven't done the "different input voltages" test. My system puts out 13.2 volts for a very long time so I'm not too worried there. When I was doing my research into these chargers, I found that others have confirmed the manufacturer's claim: Each cell is individually managed by the microprocessor, so one cell or four cells doesn't matter.

 

[Wrend]

...No; you can't see my storage.

Makes me curious. Might be kind of interesting. But fair enough.

 

[vikaden]

Just got some new Eneloops and a C9000, wanted to post my discharge and break-in results. Only have the first 4 done so far, they were discharged at 100mA and then a break-in was done.

Date BIM
01/12 2012
01/12 1999
01/12 1978
01/12 1986
01/12 1987
01/12 1985
01/12 1965
01/12 1978
01/12 2015
01/12 2019
01/12 2011
01/12 2008

 

[tickled]

I recently cracked open a package of re-branded first gen Eneloops. Package is marked 2008, purchased in September or October of 2009.

After one R&A cycle on the C9000, I had capacities of around 1770mAH for one pair and closer to 1810mAH for the other two and I think impedance check of (?) of 1.6 to 1.65.

Charge rate 1000mAH, discharge rate 500mAH. I'm running another cycle right now!

 

[wshyang]

I'm a survivalist. One of my post-collapse businesses will be bartering and charging AA/AAA batteries. So I have a stockpile of AAs and AAAs that need to be consistently refreshed. Post-collapse I'll need those chargers because part of the business model is people bringing me batteries to charge or to trade and I need to be able to cover all the bases as well as satisfy a non-trivial demand level. So I have solar panels and big batteries and inverters and hobby chargers and of course these.

I'm really trying to work out if you are serious or if this is a troll post, lol.