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Sunday, January 25, 2015

My Prius Power Center/Generator

The sign here at DuPuis free camping site says no generators.  

i have a secret!

My Prius has a generator.  In fact all Prius have a generator. The Prius engine has a number of functions.

1. Generate Electricity for the high voltage batteries.
2. Power the drivetrain in conjunction with the electric motor.
3. Provide heat to the passenger compartment.

It's number 1 that is the generator.  The Prius engine/generator maintains the the voltage batteries.  The high voltage to the high voltage batteries that starts the engine not the "car 12 volt" battery.  The 12 volt battery gets its power from the high voltage battery.

Leaving the Prius "On" in Prius language is "Ready Mode".  In this mode the Prius will supply power from the high voltage battery to the 12 volt battery. Note: accessory mode will not do this.  In Ready Mode with the heat on the Prius engine will also deliver heat. With the heater off the engine will only run for supplying power & will not maintain engine heat, so the Prius runs to maintain the electricity.

I know this is a lot of technical detail you may not want but it's important for this next point.

Since the engine will only run to maintain power you can tap into it and in my case running my Engel Fridge and charging my iPhone and IPad the engine only runs for 2 minutes every 45 min to an hour.

You can tap into the Prius for power two ways.  One is into the high voltage to run a DC to DC inverter for about 2000 watts or as I did tap into the 12 volts for up to 900 watts.

My choice was to build a power center over the Prius battery as shown in the picture above. 

The house switch connects to the 12 volt battery below (yes Prius battery is in the rear).  I then put in a volt meter with dual USB power and a cigarette lighter plug for high power 12 volt items like my water heater.

This water heater may draw more power than the Prius supplied power outlet will supply and I risk blowing fuses.

On the right of my panel is my 120 volts that I get from a 400 watt pure sign wave inverter.  I didn't go to the 900 watts because of size and didn't need to want to max out what I could get from the Prius or damage the 12 volt battery.

The black box to the right of the inverter is a 100 amp circuit breaker that I leave disconnected unless I am using it as the inverter will draw power if just on and nothing plugged in.

I also went with oversized cables to prevent losses.

The volt meter tells me the status of the Prius battery as you can use the 12 volt power withou being in ready mode but do not want to get down below 12.5 volts before turning on the Prius in Ready Mode.  The make auto disconnects but I didn't add it and will see how my trip goes.

I left the Pruis in Ready Mode until I went to bed and since I got up this am.  I monitor the temperature in the Engel fridge remotely.  I will cover this in another post.

Oh, I got the inverter and water heater from Amazon.



  1. It's number 1 that is the generator. The Prius engine/generator maintains the the voltage batteries. The high voltage to the high voltage batteries ...

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