Grand Design Solitude ST310GK
System Schematic

Basic Parts List

Installation Notes

This installation was completed in October of 2023.  The owner of this 5th wheel learned of my services through a Grand Design owner’s forum and  contacted me regarding a possible installation.  After discussions about the owner’s needs and budget, we worked out a system design and set a date to move forward with the system installation.  The owner provided three Battle Born 100 amp hour batteries for the installation, but nothing else. 

This is the eighth time I have completed an installation on this particular Grand Design floorplan, so I was pretty familiar with the way I thought the installation would go.  I ran into one snag, in that the owner installed a whole house vacuum system and the vacuum module was in the way of where I would normally install the batteries.  I was able to make room for the batteries under the interior stairs behind the basement wall though, so I did not have to relocate the vacuum.  The installation took three days to complete.

Once I was done, the owner returned to pick up his rig and I spent some time with him going over all the equipment and the Victron Connect App to interact with the equipment.  I also went over the VRM portal and how that monitored and controlled the system.  We also set up a VRM widget on the owner’s phone to monitor the system.

As I was demonstrating the auto generator start functionality to the owner and explaining how the GSM-mini generator control module took the simple Cerbo Relay 1 NO/NC signal and converted it to a signal the Onan 5500 watt generator needed to start/stop, I realized I hadn’t combined the generator output to allow its full power to pass through on L1.  This is a specific issue to the Multiplus II 2×120.  When it senses the incoming power on L1 and L2 are the same phase, it ignores the L2 input and only passes through the L1 input.  The Onan 5500 generator has an L1 and L2 output, but they are in the same phase.  Thus only the L1 output will pass through the Multiplus.  By adding a jumper wire between the generator’s L1 and L2 outputs, the full generator output power can pass over either leg.  This allows the MP to pass all of the generator’s potential power through on L1.  I quickly added this jumper wire to correct the issue.

GD Solitude ST310GK