said by bemis:
I have a large marine battery and a 2000W inverter which I have used in the past to run a few times in the house.
If I needed to extend the run-time with that battery, would it be acceptable to connect the marine battery to my car battery via jumper cables while the engine is running at fast idle?
Just remember, the car is going to recharge slower then what you'd likely be using. A car's alternator may not be that powerful. Not accounting for any current the car needs to run, or inefficiencies of the inversion process, a 150amp alternator will only get you 15 amps of power at 120v. If you're using more than 15 amps, then you'll be recharging it for just as long as you use whatever is plugged into it. And that's with a 150amp alternator. Alternators 1/2 that size aren't uncommon, so you could be recharging two hours for every hour of use (not including inefficiencies).