Charging NiMh? AA
 

I am using some EMB AA 2200mah batteries. When I bought them I charged them up and they seemed to last for ever on the charge. Now , maybe 3 charges in the charge is not lasting even half the time the first charge did. I am using them for my transmitter . I am charging them the way I did the first time , at 2.2 amps. :confused:

Just cheap batteries?

What manufacture of battery charger you using?

Thunder AC680 Professional Dual-Power LiPo Balance Charger/Discharger w/ AC Adapter for 1-6 Lipo/ 1-15 Nimh + USB to PC Software

Where is your voltage delta set? Sounds like they are false peaking. Also I would set the charge current to something like .5 amps. Does your charger tell you how many mah it is putting back into the batteries?

Good charger. Sub-c & 2/3 sub batteries I'd trust the charger for charging. AAA & AA tend to over heat. Kills capacity on AA & AAA. Charging at 2.2amps will kill them. Like Paulina says set you amps to .5a. Let in take its time to charge maybe take a couple hours.. It'll produce less heat. Or just purchase AA & AAA charger.

Also if I remember right, AA & AAA batteries are not built with a vent like sub C batteries & like was mentioned above .5 amps for long life.I would not go much higher

Ok thanks. I might have ruined them. I did notice on the first charge the were hot. I will start to charge at .5 amps from now on.

Thanks for the tip. I charged at .5 amps and the batteries are lasting a good while now.

For my Spektrum radio and other general AA's, I use eneloop and use the Panasonic's current gen peak charger that can charge cells individually. AA's last me years.

I don't know the charge rate of the Panasonic, but probably 350-500mAh. Unless these cells are meant to be charged at a high rate (like the AAA's for MiniZ's), even 500mAh is kind of on the higher side. Battery should only be warm to the touch when charged.

I use AAA charger that does 80MAH, 800mah on AA. It takes longer but it doesn't cause excessive heat, which kills batteries. Use 2700mah from CTA used for photography. they're 4 yrs old and taking the charge with no problems.

Yep, my MiniZ AAA's charger does 1A... But these cells aren't your typical cheepo's though and would be overkill for powering transmitters. Better to use lower charge rate for 'normal' AA's and AAA's.

a-1 I think you killed these batterys . as in you over charged them at 2.2 amps killing capacity.. Time for some new batts and charge at 1/5 amp tops..