I have a problem where my XM radio shuts off when I start my car. I also have a Sirius radio, but that stays running when I start my car. The XM shutting off is kind of annoying since it doesn't turn back on by itself after the car is running.
I was thinking of putting in a capacitor to provide power to the XM unit to keep it live while starting the car. I was thinking that a diode between the car power and the capacitor would be needed to keep the cap from back-powering anything in the car.
Anyone ever try this before? Any guesses on if it would work? Any suggestions on how big of a capacitor would be needed? Is there any chance the leakage of a capacitor would run down my car battery if I let it sit for days at a time?
-john-