running a fridge off an inverter setup?

The old style inverters didn't put out a very good sine wave. It was much closer to a square wave and motors don't like the DC component of square waves. Today's inverters are far superior with distortion being very often less than 5%.

What you are hearing is correct about intial surge of a refregerator starting up. The initial impedance of a refridgerator is highly capacitive which presents a very low impedance at startup. This produces a very high peak inrush current. Once that inrush is overcome, the impedance will go up and the current will drop accordingly.

A 3000 watt inverter of at least decent quality should be sufficient. That works out to around 26 amps which should handle the inrush of the fridge.

My concern would be running the fridge/inverter off of two deep cycle (group 27?) batteries. They won't last very long at that type of load. I would look at a crossover switch to move the fridge over to shore power once you've arrived at the site or home and only use the batteries while traveling. You could even use some 12vdc from your tow vehicle to run the inverter if you set it up correctly with an isolator.

Hope some of this helps,
Russ

I have done it. Honestly, by the time you do all the investment, et al. You are better off buying an LP fridge. Ive got a nice inverter and 2 massive marine batteries for sale!

Yes, use the power lead on the 7-pin trailer connector. You tow vehicle should already have a fuse on the power lead, if it was wired from the factory. However, it never hurts to add additional protection with seperate fuses/breakers at the batteries.

For the DC grounding. I didn't ground my lights, appliances, etc. to the trailer frame. In my opinion (and only my opinion), the trailer frame is not a good reliable ground return. I ran dual lead that I purchased at Home Depot that already has a protective sleave built onto it. That way all power & returns are dedicated and come back to a terminal strip that connects to the battery posts. The terminal strip also connects to the 7-pin trailer/tow connector. That way I am assured of proper current paths. I can take a picture of it if you like.

For AC, I do ground (the green wire) the trailer frame. That puts my trailer frame at earth potential as soon as I plug in. But the breaker panel and outlets are wired exactly the same way as a normal house outlet.

Russ

X2 on the LP fridge.

Be aware that the current draw on the AC side may only be 25 amps (peak) but on the DC side it will draw about 250 amps (peak). So size the primary wires accordingly and protect the wiring at the power source (fuse at battery, size fuse according to wire size).

Yea, I was going to suggest LP before Scottie and Paul beat me to it. RV's with inverters often have 2 deep cycle batteries. RV's with a fridge hooked to the inverter have 6 to 8 batteries. That should tell you everything you need to know.

EZ Freeze, Crystal Cold, etc. There are a bunch of propane refrigerators made for (and sometimes by) the Amish and people with remotely located homes or hunting cabins. Propane refrigerators have to be kept strictly level. RV fridges (Dometic, Norcold) could probably be rigged for a comp trailer, and would probably handle bouncing around during travel a little better.