caravan wiring

Most likely

Check out the lights. If you have 240v and 12v globes then yes it iss etup to run off the car's 12v supply. Trace where the heavy black and red wires go to in the van and you should be able to setup a battery for the van.

Peter

The anderson plug with the heavy wires could be to power the 12v on the 3way fridge

The anderson is "usually" wired to run the fridge when driving and in some cases to charge the battery whilst driving also. Strange to have no battery, no doubt you have checked the obvious places, front boot, under lounge seat, under bed, very unusual for a modern van with 12volt lighting to not have one. There must be a power supply for the 12 volt what brand is the van and charger? Could help to know.

Hi Twinkles
Is it a brand new caravan or is it a used new one to you
I would look at the manual that came with the van
Older caravans were sold with only a 240 volt system and the 12 vol just fed the Fridge
Some of the older had to system with the lights they had a 12 v and a 240 v globes in the light fitting
Terry

Thanks everyone. Will explore a bit further