What the heck happened to my batteries?

I have some Lenmar 2000mah AA NiMh batts that have been put away for probably 4-5 months. They were fully charged before then. Yesterday I put them in the charger, expecting them to be dead, but the charger said they were done after just a few minutes.

Then I put them in an incan flashlight that draws about 800ma. They lasted maybe a half hour before the light went out. I tested them with my DMM, voltage was about 1.25, but when I shorted them they were only good for about 180ma. Put them back in the charger, again the charger said they were finished way too soon.

Anyway...why would they be doing this? I can understand one or two going bad, but all four dying at exactly the same time? They aren't very old either. I'm not too concerned about saving these batts, I'd just like to prevent whatever happened in the future. Leaving them sit for a few months isn't THAT bad is it?

The full charge before storage may have contributed to their earlier than normal demise, but they shouldn't have died that quickly. IMO Lenmar cells are junk, at least the various 2000-2300's I had. Over half of them died similar deaths within a 6 month timeframe, so I just gave up on all of them and pitched 'em. I may have to do the same with the 2000's that came with my BC-900, they're losing significant capacity already.

Chris

Yeah, they weren't very good cells...I tested their capacity a while ago and they were only around 1700mah, and the voltage curve wasn't flat at all. Why would charging them up before storage be bad for them? I thought it would be better since they would spend less time at zero charge.

Sounds to me like they need to be cycled just like when they were new. That would account for the short charging and run times. It happens when rechargeables are stored for a 'long' time.

Not sure if you guys remember my thread about having brand new 1800/2000mAh PowerEx AA still in wrappers and in plastic cases, some of which leaked. Even after forming, cycling. etc., none of the 1800mAh made it but only two 2000mAh were chucked! Thirteen cells in all!

I've read several times and on MAHA's site, that cycling will bring them back to life! Yeah, sure!

Are the cells warm or hot when they're done charging ?
If it is still cold/ a littlle warm, then it is false peak. Just keep charging them as long as they're not too hot to touch.