Grand Design Reflection 303RLS
System Schematic

Basic Parts List
- 6 -Battle Born 100 amp hour batteries
- Victron Multiplus-II 12/3000/120-50 2 X 120V hybrid inverter charger
- Victron Cerbo GX
- Victron GX Touch 50 Display
- Victron BMV-712 with Display & Bluetooth built in
- Victron MPPT 150/100 Smart Solar charge controller with built in Bluetooth
- Victron VE.Bus Smart Dongle – allows Bluetooth connectivity to Multiplus
- Various Victron VE.Direct and RJ-45 Cables
- Victron Lynx Distributor
- Various Victron Mega Fuses for Lynx Distributor
- 17 Feet 4 AWG Welding Cable - Red
- 14 Feet 4 AWG Welding Cable - Black
- 5 Feet 2/0 Welding Cable - Black
- 4 - REC Twinpeak 2S Mono 72 Series 365 Watt Solar Panels
- 24 - Aluminum Solar Panel Mounting Z Brackets w/ Stainless Steele Hardware
- 2 - Micro Air Easy Starts
- 2 - Mopeka Bluetooth LPG Sensors
- 3 - Ruuvi Bluetooth Temperature Sensors
- Blue Sea 3000 Battery Switch HD On/Off
- Midnite Solar Baby Box
- Various Breakers for Midnite Solar Baby Box
- 13 Feet of 4/0 Welding Cable - Red
- 14 Feet of 4/0 Welding Cable – Black
- 10 Feet of Portable Cord Soow 6/4 6 AWG 4 conductor
- Red Dual Wall Shrink Tubing
- Black Dual Wall Shrink Tubing
- Various 4/0 Tinned Copper Lugs
- Various 4 AWG Tinned Copper Lugs
- Various 2/0 Tinned Copper Lugs
- MC4 Male/Female Solar Panel Cable Connectors
- MC4 "Y" Solar Panel Cable Connectors
- 30 Feet 10 AWG USE-2 Black cable
- 30 Feet 10 AWG USE-2 Black cable
- Miscellaneous parts, sealants, breakers, and connectors
Installation Notes
This installation was completed in July of 2023. The owner of this 5th wheel contacted me regarding upgrading the OEM solar installed by Grand Design. The owner had already replaced the OEM battery with two Battle Born BB10012 batteries and a Victron BMV-712.
We discussed what additional equipment he wanted and I presented a plan, to which he agreed. We set a date for the installation and I ordered all the parts. The customer brought the rig to me for the installation appointment and I completed the installation. This was the third installation I completed on this particular floor plan, so I had a good idea how it would go. All of the equipment was installed behind the rear wall of the basement storage area and under a cabinet in the main living area. The cabinet backed up to the dead space behind the basement wall and the rear of the cabinet opened up into that space. The customer did lose the bottom drawer in that cabinet as a result of the installation, but I was able to cut down the full drawer into a shallow tip out container. This allowed for some remaining storage in that area. The customer also gained additional space in the generator compartment because the batteries were removed from that area as part of the installation.
I was able to fit all six batteries on the floor under the interior cabinet. Actually three of them went on the floor and the other three were installed on a shelf I added over the water heater that was hidden under that cabinet. The inverter and Lynx distributor were installed behind the cabinet in the dead space between it and the basement wall. The only equipment visible to the user without opening a door or removing a wall were the main battery cut off switch and the MPPT solar controller I added. The cut off switch was installed on the ceiling of the basement storage area and is easily accessible from the passenger side basement door opening. The MPPT solar controller and solar breakers were installed on the rear basement wall just inside the passenger side basement door. I also mounted the display for the BMV-712 next to the solar controller so the owner could check battery information while outside the RV without the use of a wireless device.
The 5th wheel had 10 AWG wire pre run from the roof, which was used to connect the REC solar panels to the system. The panels were run in series parallel to utilize the smaller gauge wire. I also installed Micro-Air Easy Starts on both air conditioners as part of this installation. Once the Easy Starts were installed and programmed, the inverter was easily capable of running either air conditioner with no issues.
Finally, I installed Mopeka Bluetooth LPG tank sensors on both propane tanks and three Ruuvi Bluetooth temperature sensors in the rig. The temperature sensors were installed in the refrigerator, the inverter area and outside under the pin box. All of the Bluetooth sensors integrate into the Cerbo GX and display their information there and through the VRM portal. This is a very nice and robust system and is capable of powering the entire trailer with no issues.