2008 Prius electrical modifications

1400 watts isn't far from the maximum output of the car's DC/DC converter, total—and some of that still has to run the car.

You'll likely get away with it as long as those are peak power ratings of your added equipment, and it won't be playing anywhere near peak output as a constant thing.

You might want to pick up an extra LED and resistor and wire them to the IDH signal from the DC/DC converter; that's the signal it asserts to say "I can't keep up this output; shed load!" (In the stock setup, it is only used to shed the ~ 700 watt electric heaters in cold weather.)

-Chap

 

a friend had 1 jl audio 12" in a properly tuned box in his suburban. he might have had a 400w amp. anyway, that single 12 made way more bass than you could ever need in a car. you might want to go a little smaller than a 2 12 sub, cause the prius is kinda flimsy and will vibrate so much it will sound bad. someone did it a few years back, and the hatch rattled really loud. it sounded terrible.

 

I have similar plans once I find a place to put my 1kW amp. Now I am running the fronts (stock) and a sub from a 4 channel amp (at about 300Wrms).

The stock battery is quite small. It only has to run the computers on start up. Once that is taken care of, the DC-DC inverter takes over.
When I had to replace my stock 33Ah (or something) battery, I replaced it with a 55Ah deep cycle (not planning on deep cycling, but for the reasonably light use it gets in the Prius, it may last a decade AND be big enough to let the car sit for a month*...). Now I have some more faith it will be able to keep up with my intended upgrades.

As with a normal alternator, all energy must ultimately come from petrol. And I don't know how the DC-DC converter handles going beyond the maximum current it is designed for. But imho a bigger battery will help out with peaks better than a small one. So as long as you keep using your common sense, I think you'll be fine.



* there are stories about people finding their stock battery dead after a month on the airport parkinglot. Mine was fine after 9 weeks of holiday (I did charge it before driving again, but it was still at over 12.5V iirc)