Lynne Jayzee
If your batteries are not holding a charge when your RV is parked and power is shut off to unit, then it might suggest new batteries. Do you have a generator?If you are parked with no shore power and are allowed to start your generator it should charge up the batteries,if they are any good, but slower than if you drove the vehicle and had the alternator from the truck charging the batteries while you are on the road. I am not sure how long it would take to charge the batteries if your vehicle was stationary with the engine running. I can charge my depleted single house battery in about an hour via the generator although some argue that is not possible. Where i live it is mild in winter so I just leave the battery in the vehicle, make sure power is shut off to RV and attach a small solar panel which trickle charges it. If in a cold climate better to remove the battery(ies) and keep in the garage or basement,preferably plugged into a trickle charger. With any luck you may be ok on the trip but if you have NO generator then you might have to run the engine enough to charge up the batteries.As for the engine ie truck battery it should be started occasionally in winter if you are leaving it in the vehicle. A battery can ``freeze`` up in very cold weather if left too long unused. Water levels in house batteries need to be checked too as a low cell can cause battery failure. Hope this helps a little.