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gareth magennis

"hr(bob) " wrote in message
...
On Dec 11, 11:29 am, powrwrap wrote:
My son noticed that the battery area of our TV remote was quite hot. I
immediately removed the batteries, both were almost too hot to hold
onto. Sorry, I didn't check to see if the batteries were installed
with the polarities correct. They had gotten so hot that the plastic
surrounding the negative terminal that connects to the PCB was
slightly melted and deformed.

A new set of batteries did not cause the remote to function.

I disassembled the remote and completely cleaned it. Scraped gunk out
of the holes in the remote casing with a small jewelers screwdriver
followed with a toothbrush and soapy water. Cleaned the flexible
plastic sheet that functions as the button pad with soapy water and
toothbrush. Completely dried everything with a hair dryer. Carefully
pulled on spring for neg. terminal, stretching it so it will retain a
battery, reassembled and put in fresh set of batteries. All is well.

What caused the batteries to get hot?

If the batteries were making poor contact with the negative spring,
that in itself could have caused localized heating right at the spring.

How so? The maximum current draw of the remote can't be very much at all,
so how can this max current through the dirty contact resistance cause so
much heat as to melt the plastic? Am I missing something?

If the remote is too hot to hold that can only be caused by pretty much
shorting out the batteries or the batteries shorting out each other.

Gareth.