Use TC without battery installed

On shore power the converter will supply the 12V DC System......so depends on year/make/model of converter. Some need the trailer battery as a 'load'.
And need to make sure battery cables are taped/isolated as they will be hot

While connected to truck via 7 pin.............NO
TC running lights/brake lights/turn signals will work as they are fed from truck
BUT TC 12V DC System is supplied by TC battery. 7 pin has a 'charge' line from truck to maintain TC battery. No Battery NO 12V DC in TC

What Old Biscuit said, except the charge line (if equipped) will run the 12v stuff so long as the current demand is somewhat low since the charge wire is usually light gauge. I've turned my battery disconnect switch off and still had power in the camper via the charge line. It's how I proved it was working. Appliances using a little DC power should be ok, but my Happijac jacks say to not run them with a low battery so I'd say no to running them from a converter. Charge line would be far too weak for those.

On running the jacks, IT DEPENDS.

Jacks take a lot of current, and the converter may not be able to supply enough to run the jacks. I've read a lot of posts over the years from people whose jacks won't work, "even though they're plugged into shore power." The cure was often a fully charged and connected battery.

The 12VDC Distribution panel gets its 12VDC from both the Battery and the On-Board Converter/charger unit if it is plugged into shore power or generator.

I always have my batteries on-line when on shore power. They make a great buffer for the converter circuits and will smooth thing out. Also gives you more capacity for the higher current demands like the jacks or the slide-outs...

Of course in our use of TRAILERS the battery is required by DOT to have while towing the trailers to activate the ELECTRIC BRAKEs on the trailer in the event the trailer becomes disconnected from the tow truck. This would not be a requirement for the Truck Camper.

My camping world revolves around camping off the power grid in OFF-ROAD mode so my batteries are the most important items I have...

Roy Ken

The jacks won't be able to lift the camper. They might run, but they won't load.

I don'r remember where I read it (or heard it), but I think there's either a sticker, or something in the manual, that says not to plug in to shore power without a battery in it.

I'll try to look over my camper today to verify. I don;t want to spread bad info...

Over the years technology change and converters come with different configurations.
Older converters would supply 12V AC (!) for lights and only small amperage DC for radio and battery charging.
New converters with controlled voltage are parallel to battery and will supply rated DC power to everything.
On my 2004 model the converter is too small to operate jacks, but they will operate on 30 amp pickup plug.

I'm not really understanding why not to use a battery. Almost everything in the camper is 12V. Of course, you could always use battery powered flashlights and not use the furnace.

I personally wouldn't try it since there could be unintended consequences.

pcoplin wrote:
I don'r remember where I read it (or heard it), but I think there's either a sticker, or something in the manual, that says not to plug in to shore power without a battery in it.

I'll try to look over my camper today to verify. I don;t want to spread bad info...

Depends on your converter. Some of them need the battery to regulate the output voltage of the converter.

An example is my TC. It's never had an onboard battery. There's no place to put one. The converter has no such restriction.

The charge line should run everything just fine except the jacks. You will need a battery to raise the camper on the jacks. The converter alone won't do it. I doubt the converter and truck would do it either.
Why not install a battery? You can get a group 24 for $75 or less.