Batteries are 12 volts, or thereabouts. When the alternator is charging, they basically overvoltage to about 13.5 volts which charges them.
Your experience reminds me of something that happened to my Dad. He said that he got his wedding ring (there is no better conductor than gold) between a starter battery cable and the block. The ring got hot instantly, and he managed to get his finger out of the ring. I suppose that had he been unable to get his finger out, he would no longer have it. Safety first. Here that Deezel?
Glad you've healed from your burns,
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in