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Old 10-10-2018, 11:04 PM   #1
Senior Member
Brand: Thor Motor Coach
Model: Four Winds
State: Ontario
Posts: 263
THOR #9081
Solar and Inverter Installed on a Four Winds 31E.

I have been meaning to document this for awhile and finally got around to it. Here is my install.
During the winter, I frequent the beautiful Southwest of the USA. I do quite a bit of boon docking there. Last summer I installed Solar , an Inverter , and a battery monitor. Last winter I added a third 100 amp/hour battery. This is my second solar and inverter install on a RV.

For the solar panel to controller, I used the 10 gauge cable which the RV came pre-wired with from the factory. The cable from the roof entry point, terminated under the rearmost dinette seat with a enough to route it through the existing cable entry into the the compartment below the dinette. In the front most part of the compartment, is where I mounted the inverter, 15 amp auto transfer switch, solar controller, and battery shunt. This compartment is next to the entry door where the batteries are under the step. I drilled holes in the rear and battery side of the compartment then used PG11 waterproof cable glands to pass all wires into and out of the compartment. Upon completion I then sprayed with foam, for further waterproofing. From the main AC Panel, I rerouted the general receptacle circuit to the auto transfer switch in the compartment. From the auto transfer switch output, I routed romex back to the first general circuit receptacle. The second input of the transfer switch is the Inverters output. Connections to the transfer switch are done in metallic junction boxes on the roof of the compartment. I installed the battery shunt behind the solar controller. The shunt and solar controller monitor cables along with an inverter on/off cable were then routed back into the RV, under the shower, behind the bathroom sink, into the wall behind the medicine cabinet then into the wall behind the control panel for the RV. I then mounted a single pole switch along with the solar controller and battery monitors in the control panel.

I purchased residential solar panels thus went with an MPPT solar controller. I purchased a 8 ft piece of 2X2 angle aluminum. Cut it to make mounting brackets for the panels, and then used the left over to mount the controller. I used -20 Blind well nuts and all stainless steel hardware to mount the panel brackets on the roof, and used screws when the bracket was over the satellite backer EGS(electro-galvanized sheet metal). After drilling the inch hole for the well nut applied self leveling dicor around the hole, then inserted the well nut and bolted the bracket to the roof. I applied dicor after, all around the bracket edges. The well nuts hold the large 65 X 40 inch panels very well. The brackets also allow for air flow under the panels. I have no plans to climb on the roof or position the RV to tilt the panels, thus did not use any tilting mechanism.
Although not needed when you combine only 2 panels in parallel I used 15 amp in line fuse holders and fuses in the wiring from the panels, as a means of disconnect on the roof and future addition of a panel if needed. According to the schematics from Thor , I added up the factory pre-wire runs and it was 33.5 feet. This would mean a 4.5 % voltage drop over the run. It has not been an issue as the controller normally sees over 30 volts. Had I hooked the panels in series, then the voltage drop would be in the 1% range.
The inverter, solar controller, and battery monitor I chose were Victron Energy products. Victron is the equipment you would find in high end yachts, which are similar to our RVs *smile*. The 15 amp transfer switch is Xantrex. The inverter model I chose is no longer available. It is the predecessor to the current model that comes with a VE Direct port. As I had no intentions to monitor the inverter over blue tooth, I choose the older model, at a better price and it also came hardwired with the battery cables. These items I purchased on line from Bay Marine Supply in San Diego. From them I also ordered custom crimped and finished battery marine cables with specified lugs and shrink tubing to the color, gauges and length I required. This is a business that I highly recommend, a very easy straightforward transaction. The Solar panels I sourced locally and paid 85 cents a watt.

I attached the electrical and solar documentation . Hope this helps others.
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Attached Files
File Type: pdf SOLAR1.pdf (54.1 KB, 52 views)
File Type: pdf ELECTRICAL1.pdf (48.5 KB, 49 views)

2018 Four Winds 31Y
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Old 10-10-2018, 11:10 PM   #2
I Think We're Lost!
Bob Denman's Avatar
Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 16,805
THOR #8860


Good Sam Member 843599689
Current coach: Tiffin Wayfarer 24 BW
"History shows again and again; how Nature points out the folly of Man!"
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Old 10-11-2018, 09:39 PM   #3
Senior Member
Long & Winding road's Avatar
Brand: Thor Motor Coach
Model: 2017 Axis 25.4
State: Arkansas
Posts: 2,603
THOR #12231
Thats a nice setup. Thanks for sharing. Solar is on my list for next year.
2017 Axis / 25.4: Big Foot Levelers, Aims 1200 Watt inverter, Ceramic Window Tint, Full River AGM 6V batteries, Front Hellwig Sway bar / Rear Track Arm, Safe T Plus Steering Stabilizer, PD 4655 converter, Hard Wired Surge Guard, WEboost + WiFi Ranger, LED Headlights/Driving lights, TPMS, Surge tank, Tornado flush, Viair Compressor
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