I've done this with my 2.2 with a 750w inverter to power a few lights, radio, computer & modem, and cell phone chargers. I want to power a fuel oil fired water heater- I haven't figured it's draw, but I do know I need a true sine inverter, not the cheaper modified sine.

I'm going to buy a large true sine inverter, use jumper cables to connect another battery in parallel with the big diesel battery, use a volt meter to keep track of things as needed, and use it intermittently during the next power outage.

This is not meant as a 24 hour use whole house back up system, just as a way to keep the family a bit happier while "roughing it".

I will probably buy a deep cycle battery for the next gas vehicle that needs replacement, then use that deep cycle as the second battery in parallel with the battery in the 2.2.

Now, will we need to replace the stock alternator with a larger one?? Or just run the 2.2 at high idle maybe 2000rpm?

I will be experimenting. Chas, please post what you do as well.