Reply #20: Yep this could have been done with any car...

[skids]

If he was feeding off the 12V rather than the HV cells, then
he could have used the same inverter on any car battery. The
Prius might have been a bit more of an efficient generator,
though, considering idling cars are extremely inefficient
whereas the Prius never "idles" it runs the engine at cruising
speed while it is parked, charges up the HV cells, and then
turns off the engine. So it probably used a whole lot less gas.

The 12V battery, which is smaller than most, is charged
by a downcoverter from the HV cells. I think there are invertor
kits for the HV cells but I'm not positive they aren't just cheapo
12V kits that just don't tell you they use the 12V. It's probably
not a huge efficiency penalty -- somewhere in the 20% range --
5-10% for the downcovert, 10-15 for the invertor stage since the
higher the input DC votage on those the more efficient they can
be.