you have a converter / charger that should recharge the battery when connected to 110 vac power (shore or generator). to do so the battery disconnect switch must be set so that the batteries are connected. also, there may be a small resettable 12 vdc circuit breaker near the batteries that must not be tripped (open). do not expect to recharge the battery from the tow vehicle. at best the tow vehicle will supply a small trickle charge but it will not 'recharge' a battery.
2015 cardinal model 3825fl
2015 dodge ram 3500 dually