[mhs4771]

As long as you're connected to shore power the converter will supply 12 V, but you won't be able to run jacks or slides.
If you're planning on pulling the batteries for a while, make sure you insulate the charge cable coming from the converter to the batteries, because if it touches the chassis for even a split second you'll blow it's fuses.
I did that last summer when I replaced my four batteries, wanted to take my old batteries so I wouldn't have to pay the core charge then return to get it back.