Anything electric will decrease MPG, that being said, when the car is on the +12 battery has the output of the ECU 14 volts riding on the battery terminals. I just went out and checked on my Gen II, power off battery was 11.88 with the interior lights on, that's normal for my car, when I power the car up, the battery terminal jumped to 14 volts, which is how the Prius keeps that little battery charged! As to the question of the mpg hit, you are gonna have to figure that out yourself. But I would not beat myself up over it. You will go deaf before you really take a big mileage hit! Adding a capacitor is a waste of money in this car. If you run enough junk that you need a 1 0r 2 farad capacitor to handle the transient audio peaks the amp needs the voltage stability for, you are gonna blow the ECU. With the small space inside the car, mega watts are not needed. A simple kiloton works just fine! PS, OP, nice clean install. That is a huge box, you may loose more MPG from hauling extra weight than from power draw! Thanks for the pics, always a nice touch!
For everyones information, the battery is wired to the 12Volt and i have my amp set so low (it is low power anyways) that it has no noticable effect on consumption at all. I do notice that if sit without the engine running and play music the 12volt begins to take energy from the hybrid battery after about 15 minutes, so i try to avoid that as much as possible. I have no need for a capacitator with my setup.
Hey guys, I installed a 12 inch sub and amp to my prius c and for some reason I can't turn the sound up to loud, the entire audio shuts off until i restart the car. Everything is stock except the amp and sub... everything is wired right, If I keep sound under 25 it stays on but is nowhere near where I want the sound level... any help? I haven't lost any mpg and I am plugged into the right battery.
I had an old book shelf stereo that would do that when I had too many speakers attached. The stereo couldn't push out enough amps.
I bet that sounds great, but I hate the idea of giving up any of the already small trunk space. I was at an audio store the other day looking at subs that go under the passenger seat, and they have to stick out about 2 inches into the rear passenger's foot space, which, again, is minimal to begin with. Sigh, this is not a fun car to mod.