Start by reading the documentation that came with the rig.
Does it have an inverter? If so, was it turned on? An inverter is only as good as the size of the battery bank that it feeds off of. Typically off the dealer lot you will get 2 group 24 batteries. Just barely better than useless.
Going down the road the TV really does not put very much back into the trailer battery bank because of light wiring & distance causing VD. Solar does not put much back unless obviously under sun & exposed for long periods of time.
The new domestic type fridges are much better at power consumption than they used to be but if you don't have or don't have turned on what they need, all you have is a big cooler during the time you are on the road.