This installation was completed in July of 2021.  The owners of this 5th wheel contacted me after I completed an installation for friends of theirs.  We discussed what they wanted and I presented a plan, to which they agreed.  We set an installation appointment and got all the parts ordered.  The installation took place over a three day weekend.  I had never seen the 5th wheel until the owner showed up for the installation.  I took some time at the beginning of the installation to plan mounting locations for all the equipment.  The owner already had his Lion batteries mounted in a box in the front compartment.  I decided I could fit all the other components on the walls behind and to the right of the existing battery box.  This was all dead space due to the existing battery box and resulted in no loss of storage space for the owner.  The owner decided to start with two lithium batteries (because he already had them), but we discussed the possibility of adding additional batteries and solar later and came up with a plan for the upgrades if/when the need arose.  All the equipment went in without any issues.  The 5th wheel had no pre-run solar wire from the roof.  There were also no floor to ceiling cabinets or closets anywhere in the 5th wheel to hide a new wire run from the roof.  Ultimately I located a wire chase in a wall separating the main living area from the bathroom.  There was an upper cabinet on this wall that did not go all the way to the ceiling and stopped one third of the way down the wall because there was a couch below it.  This cabinet housed the main control switch panel for the slides, etc.  I was able to drill through the roof of the trailer between the ceiling and the upper cabinet and then enter the wire chase in the wall above the cabinet.  I ran 10 AWG wire to connect the REC solar panels to the system.  Only about one foot of the wire was visible in the trailer above the upper cabinet.  Because it was up high and the cabinet extended out from the wall, it was very difficult to see this small bit of wire from inside the trailer.  Once everything was hooked up and the desired circuits were moved from the main panel to the sub panel, I discovered some issues with the factory 120 volt wiring.  Grand Design combined the 120 volt receptacle for the RV refrigerator and a small outdoor residential refrigerator.  The RV refrigerator was not supposed to be powered by the inverter, but the small outdoor residential refrigerator was.  In order to accomplish this, I had to isolate the small outdoor residential refrigerator from the RV refrigerator circuit.  Luckily there was another receptacle near the outdoor refrigerator that was powered by the inverter.  I was able to run some new wire from this receptacle to the outdoor refrigerator receptacle to allow the outdoor refrigerator to work from the inverter.