Todd:
Do you know what brand/model battery charger/converter is installed in your trailer?
My battery system takes about 2 days to fully charge the battery system with a Progressive 9260 (60 amp maximum charge) microprocessor controlled 3 charging stages ( plus 1 daily 15 minute battery desulphation stage ) premium charger/converter between my 40 mile moves every 3 weeks as a fulltimer. The battery system gets its heaviest workouts lifting the 5th wheel pin off my truck hitch, and putting out my 4 hydraulic slide rooms every move when arriving. Similar battery demands a couple of hours previous in hitching up and getting ready to move in departure. I ALWAYS HOOK UP THE AC POWER TO THE TRAILER FIRST THING AFTER TRAILER POSITIONING AND LEVELLING WHEN ARRIVING AT A NEW RV SITE TO GET THE CHARGER/CONVERTER'S 60 AMPS ASSISTING THE BATTERY SYSTEM IN SETUP AMPERAGE DEMANDS. Likewise, I always disconnect shorepower LAST before pulling out from a RV space to give the battery system some high amperage bulk mode recharge time after the demands of slides in and lowering/raising the pin to hitch to the truck.
The charging wiring from the truck will not provide very much battery charging current, due to the small gauge standard wiring in the truck. My truck has a 25 amp fuse under the hood on this circuit, and you can never tell driving down the road if this fuse has blown, and there is NO charging to the trailer battery. This small charging circuit is mainly there to attempt to keep the trailer battery somewhat charged, so that in the event of a catastrophic trailer disconnect, the emergency disconnect lanyard switch will be pulled and activated, and the trailer electric brakes will be automatically applied. I modified my truck/trailer charging circuit with an automatic resetting circuit breaker in the charging circuit at the umbilical connector on the trailer. I chose a circuit breaker rated LOWER in amps than the fuse in my truck, so that the truck charging fuse should never unknowingly blow.
