Think of the alt as a plug in you're wall. Say you have a radio with batterries, and you are listening to it out side. that would be like you listening to you're system with the car turned off.
When you go inside, you would plug you're radio in to the wall for a constant supply of power. The plug is like the alternator.
basicly...thed alternator is a genorator...when the motor spins, it spins a belt wich spins a magnet inside the alternator wich is surroundewd by wire and sum how that make an electricle current wich goes 2 the battery lkol
The battery only runs the system when the engine's off or after your alternator takes a dump or just can't keep up with current demands and system voltage drops below that of the battery.
well sub, none of your posts were inaccurate, but a couple others were. taylor's analogy is great, and fishy is right on. when the engine is running, the alternator runs all of the electrical equipment and charges the battery. the battery is only used to start the engine and to run the electrical equipment when the engine is not on. however, when the alternator cant handle the load, the battery kicks in to take up the slack. that's why it is important to have an alternator that can handle the amount of current your car and system needs. if your electical needs are more than the alternator can handle, not only will the alt be working at 100%+, your battery will have to kick in to help it. obviously when it does it is not getting recharged, which is why the battery may be dead the next morning. in addition, if you have your alternator working at 100%+ all the time, it will eventually die, just like anything pushed to full capacity for a long period of time will. i relate it to my golden retriever. she has such strong instincts (like a machine) that she will fetch until she drops dead of a heart attack or drowns, so i have to pace her. your alternator will work until it dies or you can give it a rest - turn your system down and run it (the alt) at 80% or get an alt that will handle your system at full blast while running at 80% and it will last much longer. that's my way of thinking of it. hope it helps.
lol, i was being sarcastic lol, but right now im currently just running like 600 watts rms from an amp until i get like 3000 lol nad im waiting on a cap to come to my house, so i was wondering, what would a batcat or whatever it is called do