Can a Gen 4 prius run out of its hybrid battery in ignition on mode

Yes, that is exactly the mode described on the Toyota Japan site.
トヨタ アクア | 特長 | トヨタ自動車WEBサイト

According to the description, you enter this "emergency power supply mode" by following those steps.

1. Foot off the brake and push the power switch twice to enter ON mode.
2. Make sure "READY" is not indicated, and push the AC100V switch 3 times. *Do not allow more than 1 second in between the 3 pushes.
3. Confirm the display on MID that the "Emergency Power Supply Mode" has been enabled.
4. Plug in an electric appliance to the onboard outlet. If the ground is needed, plug the gound wire into the "Earth" plug.

 

interesting - but in Australia, we're all 240volt. Not sure if an inverter could be used?

 

If Toyota were to offer this inverter down under (or in Europe) it would produce 240v.

JeffD

 

If the frequency matched up, a simple transformer could be used, though at a 1.5 kVA power rating, it would be a bit heavy.



The frequency used in the US is 60 Hz, but I think it's 50 Hz in Australia. That's harder to deal with; easiest to let Toyota equip the car for the right frequency and voltage.