On the Metro 23 (AKA San Antonio Sewer Pipe) the ships batteries are in little dog boxes in the wing root area. On overnights in freezing OATs the ships batts are barely able to start an engine. If they're in need of service (NiCad) you often do not get a successful start. It needs careful management of the capacity available - minimal lights, fuel pump for the 1st engine on to build up line pressure, then off and wind the prop a few revolutions by hand to free up the gearbox oil.