Adding amplifier and subwoofer to Gen 1 Prius

What you want to do can certainly be done. The aftermarket head unit can be installed in the compartment below the stock unit (many gen 1's have a cd player installed there). Disadvantage is that the stock stereo stays there and is non functional. One could probably kludge the stock stereo to an aftermarket amp and ipod input.

As far as the amp install goes, there is a limited amount of current available from the inverter (I cannot quote how much off hand). Too big an amp could put too big a drain on the system. (I don't know how big is too big).

In simple terms, the prius has no alternator, the inverter provides the current to charge the 12 battery and run the accessories. So that current is available whether the gas engine is running or not.

Keep in mind is that a discharged 12v battery is the source of many gremlins with the gen 1 prius. If you load up the system with a big current draw you could be asking for a big pain in the @ss.

So I guess if I were going to do a project like this, I would:

1) Choose an efficient driver, a ported box will require less power.
2) Don't go overboard on amp power, use a very efficient modern design. (consider a Class T, can you get one to drive a sub?).
3)Do some research and see if we can get the fidelity and Ipod function elegantly with the stock radio. If not, I would do a digital media player in the slot, use the head unit amp to drive the 4 main speakers.
4) Use the best 12v battery you can fit, probably an Odyssey. Which will require some customer wiring, but nothing major.

If you decide to do it, snap some pix and tell us how it works out.

Eric

 

In the wiring diagram, one of the signal wires at the inverter is labeled IDH. If I remember right, one place this wire goes is the heater control, and while I haven't tested to confirm it, my theory is that this is the signal that tells the heater turn off the supplementary electric heat when there is too much other electrical load. If I'm right, you could also use this signal to tell when the amp is drawing too much.

Maybe you could arrange the signal to automatically mute it. Or, design some circuit that can send this signal to the heater when your amp is on so you're not fighting over the available watts. If you know you've already disabled heat and the inverter is still saying "IDH!" then you'd know it's your amp drawing too much.

You could power the amp from a capacitor bank, with a current-limiting circuit supplying the caps. (The 12V bus is fused at, I think, 100 or 120 amps at both the inverter and the battery ends, so you'd want to choose your current limit to avoid blowing fuses.) Maybe you could let the IDH signal select a lower value for your current limit.

Note since I haven't tested the exact function, voltage levels, etc. on the IDH line, somebody'd have to do that to figure it out.

-Chap

-Chap

 

Cool idea. I wish had the time to try it. Alas, I will have to wait to hear about it from another PriusChat enthusiast.

Eric