If you have a 12v. Checkout how many watts it can handle. If it says 120w and you get a 100w heater for a back to try and stay a float. Then I say give it your best shot. There is ones you can connect to a car battery that are 400w-1000w I think at Homedepot. You just need to keep your car running and use it like a generator. I think that's the whole idea of it.That is also my dilemma: "How to power my heaters in a weather emergency" (or any emergency for that matter) that causes an extended power outage. I've got a 120 gallon tank, with two 300 watt heaters. In an ice storm or blizzard, the tank is going to eventually get too cold, and corals and fish won't be able to survive. I have an Ecotech battery backup for my MP40s, but of course, I can't use that for the heaters.
So if I have a 12V outlet in my car, are you guys saying that I can simply run an extention chord from the car into my apartment and power those two heaters ? (Unfortunately, a generator is not an option for me, as I live in an apartment).