Small Trailer Whole House Solar System
Roddy Slaughter
March 2022

My Grand Design Imagine XLS 22MLE came equipped with a 165 watt solar panel on the roof and a 25 amp MPPT charger controller, both Furrion products. I decided prior to buying my trailer that I would immediately install a Whole House inverter power system with the following requirements:
At least a 3000 watt inverter.
At least a 400 amp hour Lithium battery bank.
As much Solar on the roof as the square footage will allow.
Automatic 120V AC Transfer Switch.
Adaptive 4-stage Battery Charger.
Bluetooth monitoring of the Solar input and Battery Bank state of charge.
Installed in a climate controlled environment.
Air Conditioner Soft Start for very limited use while boondocking.

For this installation I needed to reconfigure, install components, and tie things together in five areas:

The service panel below the pantry in the kitchen.
The storage area under the bed for battery and inverter/charger installation.
The pass through compartment to install the Victron Charge Controller & DC Circuit Breakers.
The trailer tongue to remove the battery connections there and tie the new battery bank to the tongue.
Additional solar panels on the roof.

Power No Matter Where I Am


Inverter and Battery Bank Installation

Like most travel trailers, the dealer installed battery was a 100 amp hour deep cycle lead acid battery on the tongue of the trailer. I decided to install the batteries and the Inverter/Charger/Transfer Switch in the storage area under the bed. This satisfies the size issue, better climate control, and security of expensive equipment.

Pictured here are two 200 amp hour Ampere Time Lithium Batteries and a 3000 watt Sun Gold Power Pure Sine Wave Inverter / Adaptive 4-stage Battery Charger / Automatic 120V AC Transfer Switch. I used short 4/0 gauge wires from the inverter/charger to the battery bank via the Bus Bars. I used short 1/0 gauge wires for the parallel battery interconnects. In this photo the DC side of the inverter is on the right and the AC side is on the left. I used 1 inch packing foam below the inverter as a shock damper. The total weight of the pictured components is 155 pounds. Very Important: Be sure to subtract your installation weight total from your payload capacity as the majority of the under bed storage transitions to tongue weight.

Under Bed Storage Area [Enlarge] 3.8mb


Victron Smart Shunt

Not pictured and located behind the Battery Bank is the Victron Bluetooth 500 amp SmartShunt. The SmartShunt, used to accurately monitor the battery bank data and State of Charge, is centered on the Black Negative 4/0 Gauge connection between the Negative Bus Bar and the Battery Bank Negative outer edge.

Victron Smart Shunt


400 Amp ANL Fuse

The Spartan Power 400 Amp ANL Ceramic Fuse & Holder is centered on the Red Positive 4/0 Gauge connection between the Positive Bus Bar and the Battery Bank Positive outer edge.

Inverter and Battery Bank Installation

NOTE: This is a depiction of the DC electrical connections and does not display the actual connections to the bus bars.


DIY Battery Connection Bus Bars

I purchased a 12 inch x 2 inch x 1/8 inch piece of solid copper and cut it in half to build two 6 inch Bus Bars for my battery connections. There is a positive Bus Bar (left) and a Negative Bus Bar (right). The Inverter connections are 4/0 gauge wire and connect to the outside edges of the battery bank. The battery interconnections are 1/0 gauge wire. The connection to the 50 Amp Charge Controller is 6 gauge, and the connection to the tongue distribution area is 6 gauge. I connected the shunt Bluetooth power to the positive bus bar.

DIY Battery Connection Bus Bars [Enlarge] 1.8mb


The Service Panel

Drawers removed for easy access

My trailer has a 30 amp AC service panel with a 30 amp main breaker, four 15 amp breakers for various AC circuits, and one 20 amp circuit breaker for the 20 amp 15k BTU Dometic Brisk II air conditioner. The service panel is located below my pantry and a set of 3 drawers which were easily removed to access the wiring to the service panel, as well as the 4 inch underbelly access hole. First, I removed the service panel door; then the shroud around the service panel (4 screws); then I removed the service panel from the pantry (4 screws).

AC Breakers in the Service Panel


Removing the 30 amp Main AC Breaker

The task here is to remove the 30 amp main breaker and the 10 gauge shore power wire associated with the main breaker. Of course by this point you should have completely disconnected your trailer from shore power. The main breaker wire (Orange in my trailer) is a 10 gauge 3 conductor with the Hot Wire (Black) connected to the breaker, the Neutral Wire (White) connected to the Neutral Bus Bar, and the Ground Wire (not insulated) connected to the Ground Bus Bar. I disconnected the Hot from the breaker and the Neutral and Ground wires from their bus bars. I pulled the 30 amp breaker and set it aside for now. Next I removed the tension restraint where the 30 amp shore power line enters the back of the service panel and pulled the 10 gauge wire out of the service panel. The shore power connection is now removed from the service panel and I'm ready to insert my 10 gauge loop to and back from the inverter.

Removing the 30 amp Main AC Breaker

Removing the 30 amp Shore Power feed

Service Panel Schematic


Connecting the Service Panel to the Inverter

Now it's time to gain access to the underbelly to connect the service panel to the inverter installed in the under bed storage area. I removed 20+ screws to easily pull two equal length 10 gauge wires labeled on both ends of each. I ran heavily insulated 10 gauge wire from the 30 amp shore power AC to the inverter input. I used the same 10 gauge wire from the inverter output to the 30 amp breaker in the service panel. I did need to drill an access hole under the bed to install the new wiring. The floor below the pantry behind the service panel already has a 4 inch hole for wiring and pex.


Connecting the Service Panel to the Inverter

As described earlier, the inverter has an Adaptive 4-stage Battery Charger. One of our two 10 gauge wires will deliver the 30 amp shore power to the inverter so I'm charging the battery bank any time I'm plugged into shore power. On the service panel side I wire tied the new wire to the orange 10 gauge wire I removed from the 30 amp Main Breaker. This wire goes to the inverter input. Again, this wire is clearly marked so there is no confusion on the inverter side between input and output.


Connecting the Service Panel to the Inverter

The AC side of the inverter is depicted here. I'm using the hard wire AC Terminal labeled number 11. The wire extending the orange 30 amp shore power wire is connected to the Input Side (L)ine, (N)eutral, and Ground. To complete the loop back to the service panel, I connected the other wire run through the underbelly to the Output Side (L)ine (black wire), (N)eutral (white wire), and Ground. I returned to the service panel and connected the Inverter Output Side wire to the service panel 30 amp Main Breaker I removed earlier. Black wire on the Breaker, White wire on the Neutral Bus Bar, and the Ground wire on the Ground Bus Bar. I reinstalled the breaker and service panel.


Disabling the Service Panel Ingegrated Converter

My trailer's Service Panel has an Ingegrated Converter (charger) designed to charge the battery all the way forward on the tongue of the trailer. That battery no longer exist and I have a much nicer Adaptive 4-stage Battery Charger ingegrated into my new Inverter. I need to remove the original converter (charger) from the 12 volt system. The DC side of my service panel does have a single Reverse Battery Protection Fuse to protect the integrated converter from damage when someone accidentally reverses the polarity of their battery. If this fuse blows, the converter stops working. Lightbulb! I removed the fuse and the converter was disconnected. Apparently this fuse only serves to protect the converter as no other 12 volt load was affected and the rest of the 12 volt system works perfectly. So I have removed the fuse to disable the integrated converter without ripping it out or having to cut wires. NOTE: There are service panels out there with multiple Reverse Battery Protection Fuses so that would take a bit more testing and other considerations.


Re-Connect Power to the Tongue

I removed the dealer installed lead acid battery on the tongue and in this photo you can see the distribution point where that battery connected. I had a 50 foot segment of 6 gauge red/black wire and used it to re-connect the tongue to my new battery bank. There are a host of components that get power from this location. The wire pair I removed from this location connecting the original battery was quite a bit smaller so the 6 gauge wiring to the new battery bank is overkill but, if you have it, use it. From this location I ran my 6 gauge wire into the underbelly along side other wiring that entered the underbelly. From there I drilled an access hole into the floor of the pass through storage compartment. From there I drilled an access hole through the lower half of the rear wall where my wiring entered the under bed storage. I then crimped the four wire ends and made the connections to the battery bank bus bars. I decided not to remove the service panel integrated converter/charger wiring just in case I have an emergency and need to use the original converter/charger again. To the right is the 7 Gang Junction Box fed from the truck's 7 pin connector. That's just FYI, there is no need to open this junction box for this project.


Added Three Additional Roof Panels

I have added three BougeRV 180 watt panels to the existing Furrion 165 watt panel for a total of 705 watts. I have these wired in a series and parallel combination, two left side panels in series, two right side panels in series, and the two sides combined in parallel to be delivered down to the charge controller. These are 12+ volt panels which are now configured in two 24+ volt pairs. MPPT charge controllers specialize in resolving the 24+ volt panel pairs in a 12 volt system.

I DO NOT like the entry gland with the non-standard connectors and will be swapping that soon. This total gives me 705 watts on the roof feeding a 100 volt | 50 amp charge controller with a max load of 700 watts. In reality, 705 watts is only achievable in perfect optimal conditions. Obviously panels mounted flat on an RV roof will never be optimal unless you are on the equator and I will not be pulling this trailer down there. When I replace the entry gland I will have standard MC4 connections throughout. Don't forget to order plenty of Dicor Self-Leveling Lap Sealant to waterproof the panel mounting brackets.


Replace the Furrion Charge Controller with a Victron Bluetooth Unit

To satisfy one of my original requirements, I decided right away to replace the 25 Amp Furrion MPPT charge controller with a 50 Amp 100 Volt Victron MPPT charge controller with Bluetooth monitoring. The Victron charge controller displays the Solar Voltage and Current as well as barrery data. I set Victron Connect to replace the charge controller battery data with the more accurate battery data from the Victron Smart Shunt.

Victron Connect allows you to create a little network to share data between your Victron Bluetooth devices, in my case the Charge Controller and the Smart Shunt. The Smart Shunt provides a true Battery State of Charge and shares the battery data with the MPPT Charge Controller.


Install Battery Circuit Breaker and PV Circuit Breaker

I installed two DC Circuit Breakers on both sides of the charge controller. This is to both protect the charge controller as well as a quick and simple way to isolate the charge controller during maintenance and/or a reset for one reason or another.

With my 50 Amp charge controller I'm using a 60 Amp Circuit Breaker between the charge controller and the battery bank. (Green breaker as pictured). I installed a 2 Pole 1000V 50 Amp Breaker for Solar Panels (Blue breaker as pictured). I ran 6 Gauge Stranded Copper Wire from the 60 Amp breaker to the battery bank to handle the 50 Amp charge.

The jumper connections between the Breaker Box and the Charge Controller are 6 Gauge Stranded Copper Wire.

I installed these two breakers in a 5 way Circuit Breaker Distribution Box with a 35mm guide rail. The breakers are mini 2 Pole breakers making the 5 way box perfect.

DC Circuit Breakers


Retained the Factory Battery Disconnect

As previously discussed, I ran a connection from my new battery bank to the tongue distribution point exactly replacing the dealer installed tongue battery. One of many advantages here is that I retain full use of the factory installed battery disconnect switch. The one exception is the Victron charge controller which I wired directly to the new battery bank with the new DC breaker to isolate the charge controller. The 12 volt refrigerator is not wire through the battery disconnect as it has it's own 12 volt fuse at the service panel.

Factory Battery Disconnect



Victron Connect SmartShunt With AC Running



Victron Connect 100 | 50 MPPT Charge Controller


 

Products used in this Instillation are Available Here from Amazon

 

I'm not an electrician... this is an illustration of my instillation, NOT a Tutorial.

 

Copyright© Roddy Slaughter - 2022