Hi All,
Just finish charging my 2700 GP batt and i realise one of the batt is hot to the point that it's impossible to handle, i have to leave it on the table before i can touch it without burning my fingers. Is it normal for rechargables to heat up so badly when charging?
Only one of the batt seem to be specialy hot and takes longer to cool than the other three.
I have also a set of four GP 2700mAh that I bought together with a GP charger. I read later that the high capacity batteries need a new type of charger too, one that charges each battery individually, not by pair or all the four at the same time. The one I have is a bit slow, 3-5 hours but that supposed to be better than the fast chargers. During charging these batteries get very very hot, so hot that I can not hold them for more than a few seconds after a while the charger started to work. That is normal. Those batteries have internal thermal protection so that is OK, just give them a few minutes to cool off after charge before you put them into your gear.
I actually had the same problem with one battery as you describe, and in fact even worse, one battery always flashed red (charging error) when I tried to charge it the second time, i.e. after the first use. Of course, I marked the battery as scaglietti says, I tried it in all positions, mixing with all the other three. No help, still red. I checked the battery with a volt meter and noticed reverse polarity, which I thought was strange since I only used it together with the other three in my flash. So I charged the three OK ones and when those were ready I tried the failed one by itself again, thinking to give a last chance before I returned to the seller. It charged without a problem. The battery is clearly marked but I can not see any more problems with it. Since then it has been charged at least 20-30 times without a problem.
To the best of my knowledge, the polarity can not be reversed if used normally, my flash works fine and as I said, I did not abuseed or short circuited the battery nor did I inserted reversed into the charger or the flash. So, why did it happen? :dunno: I guess it has something to do with manufacturing. I always use my flash batteries until the flash stops working since that happens without any noticable warning signs. I also have two sets of 2500mAh Sanyo batteries, and these gets also very hot every time. In fact, I feel a bit uncomfortable to charge them while the family is sleeping, so I try to do it during the day. Maybe I am just too cautious.