Auxilliary Propane

I have had a "T" fitting from the beginning. It really comes in handy with an extended stay.

Most Class A owners go with a Stay-A-While from Mr. Heater... In the old days we went with Extend-a-stay from Marshall brass but it appears MB discontinued that line, Mr, Heater picked it up, appear to be identical

Features:
Propane in from Main tank or reserve (External luggable) tank or with extension hose rented big tank.

Propane out to Motor home regulator OR via a "Quick connect" fitting to a grill or other high pressure propane appliance.

Check valves prevent flow the wrong way through the device (so gas can not flow OUT of an inlet)

I installed a "Stay a While" tee that is intended for that purpose. It is made by Mr Heater and is available in many RV stores and on Amazon. It also has a hose that can be connected to a propane grill with a built in regulator. See HERE

Another brand - Extend a Stay by Marshall Gas Controls - was popular but they quit making it for a while. It appears to be on the market again at Amazon.

A very similar one is made by Sturgi HERE

One advantage of these over a home made one is some built in safety features such as check valves.

They install between the RV tank and regulator.

We did this when we were in a "seasonal site" last winter.

The local propane company brought out a 100 Gallon (not 100 pound, 100 gallon, really big 4 feet tall, a couple feet in diameter!) propane tank and hooked it up.

They unscrewed our hose from our propane tank, and hooked their high pressure hose to the input side of our regulator.

Again, a really big tank, with a full pressure hose going into the input of our propane regulator, done by the gas company that serviced that campground.

Only way if you will be in a cold area over winter.