Connect the negative side (black -) of the inverter input to ground (bare metal!!) and run a cable from the positive terminal of the battery to the positive (red +) side of the inverter input. Put a fuse carrier as close to the battery with a suitablt rated fuse. The inverter should have a current rating on it. Get a fuse thats the same or lower. Rough calculation watts/volts = amps. So if its a 300w inverter, 300/12 = 25 A..
Thinking about it, the inverter should have its own fuse, but its better to be safe than sorry, especially when your running the live through your car!!
Id get somebody in to do it if your not sure.....
[Edited by lagerlout1 on 04 September 2004 at 5:51pm]
[Edited by lagerlout1 on 04 September 2004 at 5:52pm]