Most modern RVs come with a standardized outside propane quick-connect, although for some reason, outside appliance companies have been slow to adopt this. Most portable propane appliances come with a single regulator/valve/orifice assembly that screws onto a small propane bottle. This is not usable with the RV propane port, since the RV propane is already low-pressure, and the second regulator on the appliance leads to poor performance.
I recently bought a CharBroil "Grill 2 Go" and wanted to convert it to RV propane. Some of the ideas here are usable for other grills, such as the Weber Q grills.
My Charbroil Grill 2 Go came with a regulator/valve/orifice that had a threaded-on orifice that served as the attachment to the grill. I was able to unscrew the end piece that contained the orifice.
I bought a conversion kit intended for an Olympian grill that had an M12 x 1.5 threaded fitting. Of course, if your appliance has one of those, that's all you need. I actually have an old no-name grill that has this same fitting.
Olympian Kit:
Olympian Valve:
I adapted the Olympian grill fitting to my needs by removing the M12 fitting and attaching a 3/8" pipe fitting using JB weld. I could then use standard plumbing parts to attach the CharBroil fittings. Since the CharBroil fitting included the orifice, I had to remove the Olympian orifice.
Attach New Fitting:
New Assembly:
Ready to Go:
Of course, using JB Weld might seem to be a little unconventional, but I considered these facts: (1) JB weld is rated up to 600 degrees F, far above what this fitting will experience. In fact, the inside temperature of the grill can only get to about 500 F. (2) It is not affected by hydrocarbons. (3) I recently bought a camp stove and noticed that the regulator plumbing was assembled with epoxy rather than solder.