Battery Pack Burnout

[scwhiteley1]

Hello!

I recently built a portable stereo that runs off a battery pack consisting of twelve AA size NiMH batteries (14.4V) It has worked like a dream, that is, until today.

The stereo worked this morning, then as of this afternoon, it did not. I opened it up to see what was causing the trouble, and it appears that something caused two of the batteries to overheat, hot enough to melt the ends of the plastic battery holder.

I tested all the batteries with a voltmeter, they all checked out except two, which registered a slight negative charge.

It probably is worth mentioning that I've been charging the pack as a whole unit, with a charger designed to charge a 14.4V battery pack.

So what do you suppose happened? Perhaps a short somewhere? possible, but unlikely. Is the charger or my charging method at fault? Who knows?

 

[audioguru2]

I have some bright chaser projects that run on two or four AA alkaline cells for months. The average current is a couple of mA and the peak current is 24mA. Some also have the connector ends of some battery holders discoloured and melted.

I have a flashlight that operates from AA alkaline cells and the connector ends of the battery holder is discoloured and melted.

Maybe the contact between the battery holder and the battery is not good because the Chinese springs are not strong enough and the small resistance with current through it creates the heat.