Installing in car entertainment..any pointers?

this may not be the best place to look but there have been some on Prius Chat done such a thing. I found this thread for you to get started and wish you good luck.

Audio Upgrade with Amp and Powered Subwoofer Model 3 Tech Package NON-JBL | PriusChat

 

The low-voltage electrical system on the Prius differs from other modern cars mainly in that the auxiliary (12 volt) battery is charged by a DC-DC converter powered from the hybrid vehicle battery, not by an alternator connected to the engine.

I would still suggest being careful about how much electrical load you add. In their training course T623, Electrical Circuit Diagnosis, Toyota writes, “The circuits protected by a single fuse are designed so that normal current does not exceed 70% of the fuse’s rating.” I would suggest keeping the sum of existing and new loads on any circuit below this value, though without access to Toyota’s design information needed for a full electrical load analysis, there are, of course, no guarantees of trouble-free operation.

In some markets, Toyota sells the Prius with an optional sound system with a separate amplifier, for which there is a dedicated, 10-ampere AMP fuse, separate from the 15-ampere RADIO fuse for the head unit. See pages 3 and 4 of this wiring diagram:

http://www.toyota-tech.eu/td3ewd/EN/EM3211E.V.1_v1/ewd/contents/system/pdf/AS-SEP.pdf

Compare the version with a built-in amplifier:

http://www.toyota-tech.eu/td3ewd/EN/EM3211E.V.1_v1/ewd/contents/system/pdf/AS-BUI.pdf

(These diagrams are for European models; your car may differ.)

In the U.S., the separate amplifier is a six-channel JBL unit, installed under the driver’s seat. My car didn’t come with this, but interestingly, it does have the AMP fuse. I don’t know how much, if any, of the wiring for the separate amplifier is provided in cars that didn’t originally have it.

 

Be careful. Electrical watts consumed by an amplifier is totally different than the rated audio output in watts.
They should be related but marketing got in the way

 

That is easy to figure out how many Kw of power you want on amplifiers......
This is not impossible....how much are you thinking to dish out.....Anything is possible with .....it doesn't matter what type of is it

 

This water is way too deep for me, so I'm going to dry of and have a nice cup of hot tea. I wish you all the best in your quest for superior sound system.

 

For power consumed from a direct current system such as a car you can multiply the voltage (I would use 14) by the current consumed in amps.
14 volts X 2 amps = 28 watts.

 

For alternating current used in a home the calculation is much more complex.

 

Although the battery voltage is nominally 12V, I believe the inverter actually boosts it to 14.4V. Using 14 allows the for a little safety margin from 12V and is closer to the real world voltage.

 

You will need to invest on battery bank new wiring and capacitors......this cars don't like spikes in current draw for amplifier......
You will need more in this than what you are just thinking for one mentioned....so your budget is not adequately peaced together......
If you want to do it right ......

 

I wish i can help more.....
With your budget this is not good place to start with.....

 

I hope the frequency response of your amp isn't to high, you could pick up converter noise. The Prius is a rolling EMI generator.

 

Yes. The obvious one of sticking with the original fitting.