I was curious about if adding these would decrease my mpg since the car uses the battery and this would pull more power from the battery or are there two seperate batteries...one for the engine and one for the components?

 

Hi,

Before answering your question, I'd like to recommend getting the "Electrical Wiring Diagram" from Toyota. This will help explain where power should be tapped and systems. If it is less than 120 W., the cigarette lighter power would be an easy tap.

To decrease MPG, your amplifier and speakers would need to draw a significant amount of power. One HP ~= 750 watts and draw nearly 53 A. at 14 VDC. It is better not to add a load but your gas and choice.

There are two battery systems:
- 12 V. auxillary used for lights, radios and ordinary car electronics
- 200 V. (04-06) traction battery for MG1 and MG2 motive power

The 12 V. auxillary battery system is recharged by an inverter that takes the 200 V. traction battery and converts some of it to 12 V. (actually 13.75-14 VDC). In our 03 Prius, we can draw up to 1 kW of power from the 12 V. system to operate an emergency power UPS.

Bob Wilson

 

Simple answer is YES - a powerful audio upgrade will definitely be noticed in your MPG. Plus, I think the 12V system in the Prius is "wimpier" (technical term) than in most cars, and pulling too many amps from it might be disastrous.

All I added to my 2005 Prius was a Sirius Satellite receiver (which still uses the stock stereo system), and even that was good for about 0.5-1 mpg drop when on.

In my previous car (a Corolla), I had a killer amplifier (pulled up to 50 amps - hard wired right to the battery with 4 guage wire!) and a 12" sub in the trunk. I even noticed the MPG drop in that car! Not to mention, I trashed the alternator and replaced it with a suped-up, aftermarket one.

I would tread carefully on this one, and consult with some car-audio specialty shops, as they must already have some experience with Priuses.

 

The biggest risk are the 100 A. and 120 A. fusible links between the inverter in the engine compartment and the AUX battery (01-03 Prius). Definitely get the electrical schematic.

As for inverter power to the 12 V. system, we saw a sustained 65 A. @ 13.75 VDC into a resistive load. IF you are going to peak values above 1 kW, install a capacitor.

As for the skills of specialty audio shops, my one experience was not impressive. They blew a fuse and never found it even though I brought my manuals. Worse, most of my dash cover 'tangs' were broken off and it is now held on with two, plastic welded tabs. This by an installer whose mother has a 2001 Prius.

Bob Wilson

 

As with most things, let's say a GOOD car audio shop.

 

Bob,

Just a comment, a one hp electrical load will decrease highway mileage about 5% or approximately 2.5 MPG (your ICE load averages only about 20 hp at reasonable highway speeds to keep the car going against friction and wind resistance). I would notice even a tenth of that loss in MPG.

JeffD

 

I thought the JBL radio came with a subwoofer included with the 9 speaker sys.?

 

What's your point?

You can ALWAYS go bigger & better!

 

My point is if they put a sub in with the jbl sys, then Im sure theres a way to put something else in with out losing the mpg.?.

 

The JBL system does not include a sub. The odd speaker is the useless center speaker providing some midrange and muddying up the stereo sound.

My friend and I installed 2 rather large amps in his 05 Prius and run the cables straight to the battery (handy since it's in the back anyways). When the tunes are really cranked and the car is "on" there's a slight momentary dimming of the headlights when a deep note hits hard, I guess the DC-DC converter doesn't respond to spikes very well, a capacitor would smooth that out. No MPG difference noticed at all, and we don't expect you'll notice unless you did a very long-term scientific study. Obviously anything affects your mileage, but a good stereo is pretty insignificant compared to many other things people do with their cars.