New subscriber here.
I have a set of Sony AA size NiMH's that are the original batteries which came with the charger. Upon charging for a couple hours, they are almost too hot to hold in my hand.
Normal? Safe? Advice?
Second question: Is there any reason to fear using other brands of NiMH's in the same charger?
In my opinion, charging batteries so fast that they get that hot cannot be optimal for the life of the batteries.
I would be worried about charging any batteries in that charger.
I like the Maha MH-C401FS 100 containing 4 independent chargers with a fast charge/slow charge switch. I always use the slow charge. The cells get just a little above body temperature at the end of the charge cycle.
Not normal or safe.
if they can be held tightly without causing blisters that's fairly normal
no.
Bye. Jasen
Fast (one hour) charger using temperature rising and negative voltage slope coming from heating to detect end of fast charge and going to low charging current. Temperature rising begun around 80% charge state.
Using temperature rising was standard methode to charging NiCd-packs in many proffesional equipment and using simple thermostate or PTS-resistor inside pack to cut down charging - batteries was pretty heat in this case, and negative delta voltage detect is later invent from 1980 or so.. days modern fast charger using both metodes.
Hot batteries (~ 50 degree C) is normal for fast charger even to days NiMh-charging, but don't use NiMH batteries in NiCd-charger - NiMh have lot lower negative voltage slope compare to NiCd-batterier and NiMH in NiCd fast charger mode, ends fast charging more or less to late for NiMh and wears out very fast in this case...
/TE
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