My favorite Video Guy trick is to revive lead acid "chocolate bars"... run a dead battery in serial in a high draw 12V circuit... ie... a car battery and starter.

I'm a battery nazi... I used to work on RC Cars... those motors are tuned to run out a perfectly charged and looked after pack in 3 mins, 30 seconds... nothing worse than running 2 mins, 50 seconds of a 3 minute race.

Bren R.