I am always surprised and amazed at how much energy you can get out of today's batteries and not just the bigger one's like the forklift had but, for example, even that lowly little 9V battery that we use in our smoke alarms and transistor radios.
Several years ago, I was evaluating a new device in an industrial environment. To test the device, 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 along a spare battery. I just stuck the replacement spare battery in my pocket and carried on with my testing.
The morning wore on and I was busy taking data. My hand brushed the coveralls where the pocket was and, to my surprise, it felt warm. In fact, it felt darn right warm! I reached in my pocket and yanked out the spare battery ... and burned my fingers! I threw the battery down on the grating and wondered what the heck had caused that!
Looking at the terminals on the battery, I noticed two discolored spots on the the brass. I also emptied out my pocket and found a 'warm' quarter. Ah, ha, said I to myself - the quarter must have worked it's way across the battery terminals, causing a short which caused 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 and I always, when disposing of ANY battery, wrap it in tape so the chances of it shorting to something else are pretty much non-existant.
The amount of power that a vehicle battery can deliver for a short period of time is quite remarkable. Even the small 7amp-hour batteries can deliver a hundred amps for as much as 30 seconds. The larger starting-duty batteries can deliver over a thousand amps for a while.
Because of this ability to deliver so much current it is mandatory that proper precautions be taken to avoid short circuits of the battery wiring. If the installer of the battery cable had done the job correctly, or even if they had added an extra layer of protection, the disaster would have been avoided.
This provides all of us with a reminder about safety requirements in battery wiring designs.
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