Sanyo Ni MH AA Hot out of the charger.

tsask

Flashlight Enthusiast
Joined
Oct 6, 2005
Messages
1,758
After charging my Sanyo model HR-3U NiMH AA cells, I noticed they were both HOT!:thinking:
The charger went from red to green in a few hours so I thought all was well. The cells were not in the charger that long after being fully charged.
I was using the charger that the 2500 mAh cells came with.
Are the cells OK to use now that they are charged?

Is it safe to charge again?:poof:

Thanks

This 'problem' is a result of me enjoying my new Nitecore PD 20.:popcorn: When my 'old' Fenix L2D was outshining the PD 20 I thought something could be wrong with the cells. When I switched them, the PD 20 came roaring back with a nice bright beam.
 

SilverFox

Silver Moderator,
Staff member
Joined
Jan 19, 2003
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Location
Bellingham WA
Hello Tsask,

Hot is a relative term. NiMh cells do warm up at the end of the charge, but if the charger misses the end of charge termination signal the cells will get hot. I think of hot in terms of a baked potato. If you have to toss it from hand to hand, it is hot.

It is better if the cell temperature stays well below hot, but you can get some very good performance from hot cells.

Heat gradually destroys the cells. They are OK to use and charge again, but will loose capacity and increase in internal resistance. The added internal resistance will cause them to heat up more during charging and this results in a downward spiral ending in "crap cells."

Tom
 

tsask

Flashlight Enthusiast
Joined
Oct 6, 2005
Messages
1,758
Thank you Silver Fox. The cells were not 'hot potato hot' but were hot to hold. I could hold them; but they were hot. I didn't want to hold them too long until I knew they would not explode.:poof:
 

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