Originally Posted by OblivionLord
I've read up on how to calculate to see how much amperage your adding ontop of what the alternator can handle.
The nominal voltage of a car battery is 12V, reaching about 13.8V when charging (i.e., engine running). You take that number and divide it by the total RMS wattage your pumping. In my case my sub amp is 200 and my headunit is 20x4 = 80w. Thats 280w just for the audio being a 20amp draw added to the stock alternator that only does 65amps. This is constant as apposed to peek wattage which it will hit rarly. So my peeks are 50x4 (Hu) and 400w (sub) all being 43amp draw. This also doesn't include the other accessories that are all on at night such as the headlights and A/C since I'm in FL hehe.
If this is right then its meanning that at peek state its drawing more than 50% of my alternator amps just to keep in power which im sure is the cause of the dimming and the very low idle.
Your system is drawing nowhere near 50% of your alternator output. The amp does not put out rated RMS power continuously under normal conditions. That equation is just a rough estimate of how much your system could potentially draw, given certain conditions. You'd have to have your gains set up pretty high, be running at near max volume, and be running sine waves continuously to be near the 20A draw, much less the 43A. Most music will make your system use only a very small fraction of the amp draw from the RMS rating of the amp.
Upgrade your Magic 3 and check your grounds and you should be fine.