Power inverter

What are you going to use it for?

I have been using AIMS Power with no problems at all, ain't cheap but it works well.

 

On the off chance that you might know what gage of wire is it? At 18 feet 4/0 maxes out at about 150A or ~1800w, and you will likely see a fare bit of voltage drop. Anything smaller is a potential fire hazard. When picking a wire gage best practice is to calculate wire length round trip.
Don’t forget when picking an inverter that they are not 100% efficient, you shouldn’t plug more than 1600w into it.

I would highly suggest finding a way to get the inverter closer to the battery box. Or double up on the number of wires going to it. My 2000w is ten feet away from the battery’s and I went with 2/0. It’s a bit overkill but it isn’t much of a price difference.
Oh, and be ware of truck stop kits, they like to over estimate the wire gage and the last one I looked at had copper coated aluminum which shouldn’t be trusted to the same amperage. Get you wire from an electrical supply store or a battery shop.

 

Be sure that your engine is running as well when inverter is on...It shortens the life of some electronics in said truck/car ect..