HHmmm - I discovered all about electrical cable sizing and voltage/amp loading trying to start a glow plug engine as a kid. Having unscrewed the cylinder head and connecting a battery I couldn't see a glow. Therefore a bigger battery was required.
Took out my Dad's car battery and wired up the leads. All of a sudden the plastic coating on the wire leads went up in smoke....poof.
That lesson taught me a lot when it came to designing and rewiring the AC/DC circuits on my yacht some thirty years later.
.......I still have plans to build a pulse jet engine...now that would be fun - at a distance.