I was evaluating a new device in an industrial environment. To test it, I had a shop-made electronic test device which used a simple little alkaline 9V battery (size 522) for power. Because I didn't want to have to terminate my testing if the battery in the test device ran low, I carried a spare battery in my pocket.
The morning wore on, and I was busy taking data. My hand brushed the pocket that held the battery, and, to my surprise, it was hot! I reached in my pocket and yanked out the spare battery -- it burned my fingers! I threw the battery down on the grating and wondered what the heck had caused all that heat.
Looking at the terminals on the battery, I noticed two discolored spots on the brass. I also emptied my pocket and found a very warm quarter. Ah, ha, said I to myself -- the quarter must have worked its way across the battery terminals, causing a short which caused the internal heating of the battery. I gingerly picked up the now somewhat-cool battery, placed the quarter across the terminals, and the battery very rapidly started to heat up again.
Lesson learned: Even small batteries have the potential to heat up considerably when abused. I never carried a spare battery in a pocket with anything else metallic in it again. Now when I dispose of any battery, I always wrap it in tape so the chances of it shorting to something else are pretty much nonexistent.
This entry was submitted by Bob Groh and edited by Rob Spiegel.
Bob Groh worked for more than 40 years as an electronics design engineer, mainly in radio and communications design, with a few excursions into management, and even one stint working for an A&E firm.
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