I had a used 2003 Prius in 2005 and my first modification was to put a 1.1 kW, modified sine wave inverter mounted behind the liner in the trunk where the 12V battery was located. I ran a line to the console between the front seats with a NEMA 5-15 outlet and light switch.
For light duty loads like a laptop, I could switch on the inverter in the cabin and see the power indicator glow. But for heavy loads like the house, I would back up to the rear kitchen door; lay the hinged inverter down in the slightly open trunk for cooling, and; use a heavy duty, multi-headed extension cord into the house to "camp out" at home.
The Prius catalytic converter ensured there were no poisonous exhaust gasses and near silent operation. The car would cycle the engine to maintain the traction battery charge which depending on house load, cycled 3-7 minutes. This was enough to run the gas heater or a single bedroom air conditioner. We also had lights to the bathroom, lights, and TV and burned about 2 gallons per day from the 10.5 gallon Prius gas tank.
In 2011, tornadoes tore out the North Alabama transmission lines and a 4 day and 6 hour power outage. But we were warm at home and on a separate, day long outage, had a cool bedroom to sleep. I didn't worry about the fridge as too many leftovers and it needed replacement with something more efficient.
My benchmarks showed that with the direct to 12V terminal posts, we could operate at the inverter limit, ~1 kWh. Testing with a three level space heater to verify overload handling of the inverter, the Prius DC-to-DC converter limited power to the battery. Over +70A, the Prius battery 13.5VDC would sag so the maximum usable power remained ~1 kWh.
In rush current had to be addressed and I always added the big loads, gas heater or window AC, first. The compressor and motor loads were significant transients. Then I added the smaller lights, TV, and laptop.
Bob Wilson
