Ac question

I've run my AC unit a lot when using a 30 to 15 adapter and plugged into a 20A circuit. Air conditioning unit, refrigerator on AC, and the converter at the same time never caused a problem. The AC unit pulled about 7 amps running, ref was about 3 amps, converter varies but never that much.

I predict you will melt the 15 amp adapter if you try to run the AC. You have more power available (20) than the adapter is is designed for, you have a power consumer (RV) that can draw more than adapter is designed for. At a minimum, get an adapter and extension cord that meets or exceeds the 20 amp source.

But if you run just the fan you should be fine.

You can run the full A/C. and the converter. everything else off.

Yes you are fine to run the fan. I assume the water and fridge are on propane and the MW stays off. Converter draws very little after the batteries are charged.

Good comments. For a 50A rig I recommend a 10 ga extension which of course costs more. Also most home plugs are indeed 15A and one of many on a circuit meaning other house loads. Best to have a single dedicated 20A plug on a dedicated 20A CB.

While the above link to a AC clampon ammeter is very helpful I recommend to spend some more and get a clampon that measures both AC and DC current.

No problem running the fan and the converter. If you have a way to monitor voltage see if the Air conditioner will run. Stop the trial run if the voltage goes below 107

The length of the extension cord will make a difference, but a 12 awg HD cord should work. If only a tv in use, and as mentioned, converter not working hard, it should not be a problem to run fan only, on the AC.

You can buy a voltage indicator that simply plugs into wall receptacle to monitor available volts, or use a meter to test if you have one.

Keep in mind, if plugged into an outlet in garage, or house, is there more electric draw on same circuit, as well as the RV?

Jerry

As new as it is, I would bet you could run one A/C. The new ones use a lot less power and come with "soft starts" from the factory. This is a good item to have in your toolbox to track electric draw on lots of stuff, not just RV related. Check while everything is running and add up the values and compare with your power supply's capacity (pick the weakest link, in your case the 15 Amp adapter). You do need to have them clamped around a single conductor, though, not the whole cord. Building a real short extension cord with individual wires makes that easy.

https://www.amazon.com/Etekcity-Multimeter-MSR-C600-Auto-Ranging-Multimeters/dp/B00NWGZ4XC/ref=sr_1_2_sspa?dchild=1&keywords=amp+probe&qid=1592704516&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExUlU1TEVaVjBWQVYxJmVuY3J5cHRlZElkPUEwODk5MzI4MzRKNTNDUDc0RDQwNiZlbmNyeXB0ZWRBZElkPUEwMTI5NDUzV0lYMERDT0NEVUJKJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

It's a new 2020 trailer, batteries are brand new

You must consider the converter is running. How much would depend on condition of the battery,
You may even be able to run AC!