mockturtle wrote:
I guess what I was looking for was a radio that would work from its own rechargeable batteries without having to use coach batteries at all.
Not going to happen any longer. Even back then it required a dumb box full of batteries that you plugged your sat radio into. Simply get a XM roady and a car kit Connect the car kit to the 12VDC battery and connect it to your existing stereo system. Power draw is so small from a modern DC radio you could run for weeks without charging a typical 12VDC house battery.