rco8786 wrote:I signed up for these boards just to answer this thread..
A system will run off your alternator, not your battery, unless your car is turned off. So just turn your car on when you want to listen to music.
Not on first start. The battery immediately sends power to your amps when turning the key from "off" to "ignition" before it even sends power to the starter. If you are running Amplifiers that draw a lot of current and your battery does not have enough current to make the starter turn, then your car won't start, especially in the winter because slimline batteries do not have nearly as many cold cranking amps.
Science Experiment: Grab a multimeter and test the current going to the starter with your system unplugged and then with it all hooked up. You will see a difference.