Hot batteries? Soshine charger.

[WadeF]

I saw some CPF'ers recommending the Soshine charger from DX:

http://www.dealextreme.com/details.dx/sku.6152

I bought a pair and have used them a few times. I noticed the batteries get fairly warm when they are done charging, sometimes warmer than other times. Today I put four AA NiMH's on (Energizers), they could be over 3 years old, and they got hot, and one was so hot it probably could have burned me, and almost did but I took my finger off it quick. Is that a sign of a bad battery, or a bad charger, or is this safe for a AA NiMH? These are the 2500mAh variety.

I had selected the refresh/conditioner mode, and the batteries then entered charging mode and it was early in the charging mode when I noticed how hot they were.

 

[Mr Happy]

That charger uses a relatively high charging current compared to many chargers, especially if you only charge two cells at a time.

The disadvantage of this is that if cells have developed a high internal resistance with age and use then they will tend to get hot when subjected to higher charging currents.

You might consider treating the Energizer cells as life expired and trying some new cells to see if they run cooler. They most likely will, especially if they are quality cells like Eneloops.

 

[WadeF]

That charger uses a relatively high charging current compared to many chargers, especially if you only charge two cells at a time.

The disadvantage of this is that if cells have developed a high internal resistance with age and use then they will tend to get hot when subjected to higher charging currents.

You might consider treating the Energizer cells as life expired and trying some new cells to see if they run cooler. They most likely will, especially if they are quality cells like Eneloops.

Thanks for the info, that sounds like what is happening. I have a bunch of these Energizer NiMH's from over the years, and some must be older and in worse shape than others.

Time for them to meet the trash and for me to pick up more Eneloops.

 

[smootik]

I would concur that it's batteries.
I have some old 2200mAh ones that I've tried to refresh with BC-900. With higher charging current (actually >500mA) they get very hot, same with other high-current chargers. Charging with lower current (100/200mA) doesn't heat them at all.

In any case the batteries do not hold their charge - they keep only around 300..800mAh. Investing in new batteries was better solution, especially if you decide for Eneloops. Ever since learning about those from CPF I am satisfied with their performance.