This installation was completed in December of 2021.  The owners of this motorhome were referred to me by a friend.  The owners want to be able to travel more in the motorhome and boondock without having to run the onboard generator regularly.  The motorhome has a residential refrigerator and a factory installed Magnum 2012 inverter with an ME-RC50 remote panel.  The OEM installation did not include a battery monitor with the other Magnum components.  After speaking with the owners, they decided to add solar, lithium batteries and a battery monitor to their existing equipment.  They went with Victron components for the new equipment.  I ordered the necessary parts and then once the owners were available, we scheduled the installation.  During the installation process, I discovered Tiffin installed 10 AWG solar wire from the roof to the OEM battery compartment.  Unfortunately there was no continuity between the wire ends on the roof and the wire ends in the battery compartment.  I never could figure out why there was no continuity between the wire ends because it was impossible to trace the complete wire run without doing some major disassembly of the coach.  The 10 AWG wire was not sufficient to handle the amount of solar being installed anyway, so I ran new 6 AWG wire from the roof to the solar controller.  I was able to follow some vent pipes from the roof down to the wet bay and then run through the bays to the new solar controller location with the wire.  It took some doing to get the wires fished through, but ultimately it all worked out.  I built new battery interconnect cables for the Battle Born batteries out of 4/0 cable.  The existing interconnect cables for the original 6 volt lead acid batteries were made of 2/0, but the cabling to supply power to the system from the batteries was 4/0.  The installation too two days to complete and the owners were very happy with the final result.