A Trolley-Accumulator was used for the ground-starting of the R-R Merlin engines used on the majority of British aeroplanes during WWII.  It has a metal framed wooden box containing lead-acid cells providing either 12V or 24V, with a small petrol engine and generator on the top or one end to trickle-charge the cells between starts.  The cable connects to the battery socket on the aircraft.  MAPSL is currently restoring two of these for different clients.