Agreed Luddite, on these DC systems there are advantages to reducing the load, but in any vehicle electrical system the stator must be capable of putting out enough power to support items like the original lights otherwise driving at night would be off limits for a standard vehicle. Even if I had the lights and heated seats on it should still cope without discharging the battery.
However many years ago I borrowed my bosses new Ford Granada Exec, it was the end of the line and had everything on it. I was stuck in traffic near Brighton in rain and fog and had all the lights on, heated seat and windows and stereo, I decided to play with the electric seats, you can guess what happened next.
