[overlander63]

On for two months? Have you checked the battery (s) themselves? It is possible, though not likely, the converter has damaged the battery.
If you have a digital volt meter, turn it to dc volts, and check the voltage across the battery terminals. If it is 12.75 or above with the converter turned off, the battery is good.
Check for corrosion on the terminals while you are there, corrosion will keep the juice from getting to the battery to charge it.
Check the water in the battery wile you have it accessible, and top it off if the level is at or below the top of the plates. Only fill it to the bottom ring in each cell, you don't want to overfill and spill acid while charging.
Next, check the voltage coming in to the battery from the solar system (the one in your trailer) and the converter, after plugging in/turning back on. Voltage for the converter should be 13-13.5 volts.