Hi Andy_CC,

All stereos will cut out once insufficient voltage is provided, although what that precise voltage is I don't know.

I guess the only thing I would say is that as long as your car battery is healthy (which should usually be the case while the car is running due to the charge from the alternator) then that point of insuffcient voltage should normally not be reached.  If the stereo is cutting out, this would most probably be an indication of a battery or wiring problem.

Don't know if this helps at all?