Does age matter to NiMH?

[musicalfruit]

Just got an order from Battery Bob in and noticed the Eneloops were from April 2006. That seems kind of old. Perhaps that's why they are cheap?

Anyway, do NiMHs start aging the moment they are made like Li-Ions or do they age by usage?

Thanks.

 

[eebowler]

I do believe age matters. If you have a set of NiMH cells and not use them for a year, the normal 3-5 initial conditioning cycles isn't enough for them to reach full capacity. I once bought cells that were not performing as they should and the supplier actually admitted that they were probably stale due to the introduction of newer higher capacity cells.
Silverfox said that it can take up to 50 cycles for stale cells to reach full capacity again.

You're lucky that the cells you bought are Eneloop. I'd assume that since they have a slower self-discharge rate than typical NiMH cells, they should be in less 'stale' state and may still be at full capacity after a few cycles.

I'm not a pro though.

 

[Gazoo]

All of the ones I received from Battery Bob were manufactured in Aug. 2006.

Note as I understand it the batteries are not fully charged before they leave the factory.

I did a capacity test on four of the AAA's using my Maha C-9000 charger. The average capacity of the four was 600ma's. This was with a discharge current of 300ma's Not bad at all since they were made in Aug. 2006. Then I did a Refresh/Analyze using a discharge rate of 300ma's and a charge rate of 500ma's, and the average capacity of the batteries was 830ma.

Regarding AA's:

I tested the battery capacity of a set of AA eneloops that were dated Aug. 2006.

This was with a discharge rate of 500ma. The capacities were:

1479 ma
1486 ma
1479 ma
1488 ma

I let them rest for a few hours, then did a refresh analyze with a discharge current of 500ma and a charge current of 1000ma. After this the capacity of the batteries were:

2016 ma
2015 ma
1982 ma
2008 ma

I think you can conclude from my tests that age does not matter with these batteries.

 

[musicalfruit]

I think you can conclude from my tests that age does not matter with these batteries.

Thanks for the info. I guess a more advanced charger might have to be the next purchase. I'm currently using the Eneloop bundle charger.

Still, I think it's sort of weird that Battery Bob is selling batteries that are from April 2006. Did Bob make a really big purchase of Eneloops or did Sanyo overestimate demand and made so many that no new Eneloops are being made and places like Bob are just burning off excess inventory?

What's the newest Eneloop that anyone has gotten?

 

[cave dave]

Recent Circuit city purchase eneloops dated "Sept 06".
I looked at the dates of several of the packages in the store too, most recent I could find.

 

[VidPro]

my 2006 car was probably manufactured in 2004, i wouldnt worry about it
yes age matters depending on storage state temps and all that junk, but the first enloops i bought when they came out, work As Good As the ones that are newer, even after use.
so far it seems to be a very usefull battery

 

[BlackDecker]

Same here... the Eneloops I bought at Circuit City were from Sept '06. They seem to discharge and charge back up to 2000mah without any issues. CC is still running them for $19.99 for the 8AA pack.