How big of an inverter do I need?

[cmptrkd]

I have an outdoor kitchen with a fridge. I'd like to be able to run the fridge while running down the road. Not for the occasional weekend trip, but for our longer family trips which usually take 2 days worth of travel.

I have a 300 watt inverter with 600 watt surge that I bought years ago. I thought I'd put the inverter in the cabinet and use it to power the fridge when driving and then once stopped for camping, plug the fridge into the electrical outlet. (currently I unplug the fridge after each camping trip as sometimes we don't use it). The label on the back of the fridge claims 1.5amps and the conversion table I used says it should require around 175 watts. I wired in a 12volt plug in the cabinet for the fridge that pulls off the furnace (directly beside the outdoor fridge cabinet). My initial thought was the furnace will only be on and running when parked and at this point, the fridge will be plugged into 120v. When traveling, the furnace will be off, and the inverter possibly turned on depending on the trip. Issue is, the inverter blows the 15amp fuse once a load is placed onto the inverter. I'm guessing one of two things, and trying to be logical. Either the 15amp fuse is too little, in which case I need to run a heavier wire from the panel to my inverter and I would use an empty spot as not to increase the wire to the furnace in case the furnace would ever fail, I don't want to risk a fire. OR the inverter is too small for that little fridge.

Any help pushing me one direction or the other would be greatly appreciated!

Thanks everyone.

[JLeising]

1.5 amps at 120 volts should be 180 watts. To supply 180 watts with 12 volts would require 15 amps at 100% inverter efficiency. Given a practical inverter efficiency, you will draw over 15 amps. In fact, to deliver 300 watts, your inverter would require over 25 amps - and double that at the 600 watt surge condition.
I would temporarily connect the inverter directly to the battery with fairly heavy wires and a large (50 amp?) fuse, then plug the fridge into the inverter using an extension cord as a test - see if the fridge runs okay that way before messing with permanent wiring. At 120 volts, the extension cord doesn't need to be heavy duty (only carrying 1.5 amps, per your spec above).

Good luck!