Back in the day caps are used to lessen the load of the starting of an electric motor. Most electric motors start much faster than a gas or diesel engine. Thats what makes it hard for me to wrap my head around and say with any reliability one can safely and a frequent bases use a set of caps to start a car.
Typically caps dry out or have a dead short from the dielectric material breaking down and no longer hold a charge. Not sure if load plays a big of role or not as when caps die, the load is just greater on the power supply. Of course in this case with a car, the cap IS THE POWER SUPPLY.
