car inverter is the way to go... might also want to get yourself a cpu battery backup.. if you only run your filters off it it they last a pretty long time and theres no down time..
If your batteries run out you could also setup a drip system with some 5 gal jugs of water and some air tubing. If you set this up full time you would only need to empty water. 5 days with this setup you might need one water change.
Oh ya I wouldn't feed more than once in the 5 days if at all
yes kinda. they convert dc to ac. but i run 400watt and 800 watt inverters, a little too big for the cig lighter circuit in the car. run mine off the battery. and now i got my 12volt generator to run em.