car battery max sustained load?

[CTho9305]

How much current can you usually draw from a car battery for a sustained period of time (couple hours)? I would imagine they are designed for a very high current drain just for a couple seconds when you start the car...

 

It depends on the type of battery,a standard automotive battery will not sustain a constant current draw too long.
A deep cycle marine battery will supply a much longer current reserve than a standard battery.

This will explain it in more detail