Terry K wrote:
300 amps? How big is the motor he's cranking?

Or, he has a dirty battery terminal. My Crown Vic 302 showed me how
that works. After the dirty terminal gets warm, it's resistance starts
to go up, then it gets hot. Depending on how the terminal reacts,
strange things can happen in the course of a few seconds.

The terminal got worse until, if the car didn't start right away, it
quit trying and even the dash lights went out. An hour or two later,
it was ok. Got caught downtown after a short stop, called a cab for a
boost. Voltmeter was bouncing all over the place. Low idle speed,
engine quits.

Brownish crumbly snow around terminal connection. Clean terminals, no
more probs. The battery was a little low, but OK.

Terry K

The terminals are clean, I clean them every 6 monthes and I have had the
problem for about 5 years now.