a question

Yep most of what CharlesinGA said about setting Parking brake and Eng running.

Since we have auto levelers , we park I set the parking brake , leave the eng running.
While my DW hits the button to get the MH leveled I get the power-cord, sewer connections out of the storage and get them hooked up , by that time she's ready to run the slides out.

Once those are out , I follow up by turning the eng off, she has the windshield cover sitting on the drivers seat for me. I slip it over the door corner,shut that door , windshield , other door corner , shut the door.
She now has the electric awing out , I lay out the mat and set up the lawn chairs and small fold up table.

All this in about 8 minutes.

Mine has two batteries, which can move the slides OK when fully charged. Winnebago recommends, for my unit, running the engine while moving the slides, but I don't usually do that. However, I do plug in first, so I get some boost for that, maybe not as much as I would get from the engine alternator.

If you will soon be driving or plugging in there is very little drain on the battery.
My trailer slide draws about 10 amps for 20 seconds.

If in doubt about the battery(s), run the generator.

My Winnebago View has the slide powered off the CHASSIS battery, and requires the parking brake be SET for the slide to operate. My manual recommends the engine be operating during slide operation (for higher voltage) but it is not absolutely necessary. Later Views have the slide on the HOUSE batteries, but I think the parking brake still has to be SET.

Charles

You don't need to be plugged in. But it is easier on the battery if you are.

When I had a class c with slides, I would usually run the slides in or out with the engine running. Dick

Provided battery is fully charged slide out(s) will operate Open/Close but not for very many times.

RVs are self contained......battery provides power for all 'necessary' items----for a while