roned2b wrote:
IM sorry I should have mentioned I just bought the trailer last Dec from camping world and got a new battery with it
RV / marine batteries come in different sizes. Group 24, Group 27, and group 31. The larger battery will last a little longer than the smaller version.
How long your's will run the furnace, depends on how much you run it, and the size of battery.
Check your owners manual or have your truck checked, to see if it is wired to charge the trailer battery, while going down the road. Some trucks are not wired for that, some need to have a relay installed, and some are ready to go.