A year ago we purchased a Renogy 100 watt suitcase. From talking to other suitcase users the wires will be too short to reach sunlight. We have three 15' 10 gauge Zamp cables with SAE plugs. Renogy provided us the proper SAE adapters for our portable.
I thought I'd never use 45' of cable until two months ago in Chiricahua National Monument. We were there for 7 days in cold weather. The furnace blower is our biggest user, and despite 220 amps (110 useable) we would have killed the batteries without 45' of cable.
When running 45' of 10g cable you want the controller inside the camper, as close to the batteries as possible. 18 volts can get by on a smaller wire than 12 volts.
We installed a Victron 110/20 controller with an SAE port on the outside of the camper leading to the controller. Between the batteries and controller I installed a
20 amp fuse that can also double as a disconnect.
Enjoy,
Perry