I’m wondering if an 80 amp alternator is enough to run 800 watts RMS without issues. Anyone here running a similar setup? Would love to hear your thoughts or experiences.
It should be fine. I’m running a little more power than that on a stock alternator, and I haven’t had any problems.
Remember the basic formula: Amps x Volts = Watts.
Galen said:
Remember the basic formula: Amps x Volts = Watts.
More people should keep this in mind. It helps a lot when planning setups.
If you do a Big 3 wiring upgrade, you should be good to go.
Just avoid cranking it all the way at competitions, and you’ll be fine. I’ve run 2100 watts on a 90 amp alternator without major problems. It only drained the battery when I had it maxed out for a long time. Playing music doesn’t draw as much as people think—it’s not a constant load.
From what I’ve read, the math goes something like this: alternator output x 13.7 volts = total wattage your car can produce. Then you subtract what the car itself uses. Keep in mind that alternators don’t produce their full power at idle, only at higher RPMs. This is what I’ve learned while working on my own system. Someone correct me if I’m wrong.
It depends on whether you’re driving or idling. I had a 94 F-150 with an 85 amp alternator, and it couldn’t keep up while idling. I upgraded to 130 amps, and now it’s fine. My setup isn’t huge—Pioneer components, a 10-inch sub, and a 5-channel amp—but the battery would drain at idle before the upgrade.
You should be fine. Music doesn’t pull a constant load—it comes in waves with the beat. The battery stores power, and the alternator recharges it. Doing a Big 3 upgrade helps a lot, even with a stock alternator and battery. Most cars have thin factory ground wires, and upgrading those can make everything run smoother. Highly recommend it!
800 watts ÷ 13.8 volts = about 58 amps. You’re in the clear.