Stop in for a cup of coffee

Took the truck in for a code read and all is ok. Check engine was for a low voltage for radio and ignition. I guess when we were waiting out one of the storms on the way and I played the radio with no engine it drained the power. WTH it must be a very sensitive system?? At least I know its nothing needing fixed.
Wow. That’s either a very heavy drawing radio or a weak weak system. Went to the local firework show last week, 4 hours with the radio going and the kids DVD player and our battery didn’t draw down like that