The Little Eneloop That Couldn't

[Bones]

I seem to have an AA sized Eneloop made in July of 2006 that doesn't think it can achieve its full capacity.

Unfortunately, other than casually matching them in pairs when they come off a break-in charge, I don't really track where my Eneloops are used.

Although unlikely, it's even possible that this one has never been through a capacity check before, and may have arrived with 'diminished' capacity.

Anyway, it's now been through three full break-in charges, each preceded by a .2C discharge, and three .5C charge/discharge cycles, all on a first edition MH-C9000, and it still evidences the following numbers following a .2C discharge to 1.0 volts.

[COLOR=LightBlue].[/COLOR]
mAh: 1686
Min:  281
Volts:  1.43

Each of its break-in charges was also conducted in a different slot on the charger, and the readings remained consistent. It has no external damage either.

As well, following the last break-in charge, I let it rest for a bit, then pumped in a full 2Ah charge. The voltage climbed to 1.54 volts over the next five minutes, and the charge then terminated as it should.

Insofar as I'm aware, all my other Eneloops of similiar vintage have maintained their capacity admirably well.

So, any thoughts on further treatment to help this little underachiever reach its full potential are welcomed.

Treatment tools at our disposal include an Energizer CHM39 170mA dumb charger, a Sanyo MQN05 slow charger, a Sanyo MQH03 quick charger, a MH-C9000 first edition (0FAB01), and an MH-C9000 last edition (0H0FA).

 

[Mr Happy]

You have apparently done everything you can to restore it. It seems you have that rare item, an out-of-spec eneloop. They are not often found, but I suppose the occasional one must turn up from time to time.

 

[Bones]

You have apparently done everything you can to restore it. It seems you have that rare item, an out-of-spec eneloop. They are not often found, but I suppose the occasional one must turn up from time to time.

Thanks Mr Happy.

I guess I'll just have to be careful not to let him play too long with his higher capacity mates.

What's interesting is that if it had a typical capacity of 1700mAh stamped on its side, I would consider it a perfectly robust cell.

 

[Turbo DV8]

I guess I'll just have to be careful not to let him play too long with his higher capacity mates.

I would use it in something like my Oral-B electric toothbrush, which uses one AA. Don't let him play with bigger kids. They'll make fun of him.

 

[Hoggy]

I would use it in something like my Oral-B electric toothbrush, which uses one AA. Don't let him play with bigger kids. They'll make fun of him.

Or put it into a 1xAA flashlight!
Either way, you don't have to worry much about over-discharging it anymore.
Heck, you could even do some testing of it's LSD properties after being abused. That would definitely be more than interesting.

And don't worry, we won't call Tom's Battery Protective Services on ya.

 

[NiOOH]

You have apparently done everything you can to restore it. It seems you have that rare item, an out-of-spec eneloop. They are not often found, but I suppose the occasional one must turn up from time to time.

Fully agree. If you have a single cell app use it there, if not just recycle it. I just retired my very first set of Eneloops purchased in early December 2006. R&A cycle showed capacities around and slightly below 1600 mAh, so I decided that the time has come.

 

[Turbo DV8]

R&A cycle showed capacities around and slightly below 1600 mAh, so I decided that the time has come.

So sad. :mecry:R.I.P.

 

[NiOOH]

So sad. :mecry:R.I.P.

Yeah, sooner or a later every cell finds its way into the recycle bin doesn't it.

These cells have served me well for over two years and approximately 200 cycles, so...
Actually, the longest service life I have ever had from NiMH was from a couple of sets of Sanyo 1700 and 1600 mAh. These were the green sleeve Twicell cells. They lasted m for 5 years of use and somethimes abuse for over 400 cycles-amazing.