Almost all of our camping with the r-pod was off grid, meaning we did not have shore power, water or sewer connections. We wanted to be able to do the same with the Cougar, but it had a lot more energy requirements than the r-pod so I set out to figure out what it needed. I designed, purchased and installed the system below, almost all after we left our house. Buying large components through Amazon while on the road was challenging, as was installing them with limited tools and often less than ideal working conditions, but call it a labor of love, I got it done.
Our refrigerator is a 12 V DC compressor driven model. It draws an average of 60 W. The trailer came with a single 200 W solar panel. I paired this with the 100 Ah lithium battery from the r-pod to be able to hold the battery charge during the day so the battery could (just barely) power the fridge through the night. I knew from the start that upgrades were needed.
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| The original 200 W panel |
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| Original solar charge controller with a built in 15 A battery cable fuse. |
I added a second 200 W panel, upgraded the solar charge controller and added a battery monitor. This allowed me to actually charge the battery during the day instead of just keeping up with the fridge. This worked fine while we were just going out for the weekend (in the summer in So Cal) but it was clearly still not the final solution. The battery monitor would help me determine how much more battery/solar I needed.
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| The original panel on the right. The new panel on the left. |
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| More capable solar charge controller with breakers for the battery and panel cables. |
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| The original battery and battery monitor on the trailer tongue. |
Once we got on the road I was able to start collecting data about how much power we used on a daily basis. This ended up being about 4500 Wh if you don't include the two AC units or the electric heater. I also discovered that you only get between 25% and 50% of the panel output during peak sun hours. This meant that there was no way I could add enough solar panels to keep up with normal daily consumption. I would need somewhere between 9,000 W and 18,000 W to do so. Since we wanted to be able to camp off grid without affecting our usage that meant I needed more battery.
The next thing I looked at was how long we needed to last before we plugged in. By trial we discovered that we could last 5 before we had to refill the fresh water and 7 days before we had to dump the waste tanks. We settled on targeting 5 days of electric capacity with normal usage before we had to plug in.
The table below is an attempt to figure out how much energy we would use every day.
| Description | Power | hrs/day | Watt hrs / day | Off Grid Factor |
| Rear AC | 1600 | 4.0 | 6400.0 | 0 |
| Water Heater Electric | 1400 | 3.0 | 4200.0 | 0 |
| Heater | 1310 | 2.0 | 2620.0 | 0 |
| Front AC | 1600 | 1.0 | 1600.0 | 0 |
| Fridge | 60 | 24.0 | 1440.0 | 1 |
| Starlink | 60 | 24.0 | 1440.0 | 0.67 |
| Bathroom Fan | 29 | 24.0 | 696.0 | 1 |
| Synology | 24 | 24.0 | 576.0 | 0.67 |
| Microwave | 1000 | 0.3 | 300.0 | 0.25 |
| Keurig | 1000 | 0.3 | 300.0 | 1 |
| Furnace | 142 | 2.0 | 284.0 | 1 |
| TV/AppleTV | 35 | 4.5 | 157.5 | 0.75 |
| Lights | 122 | 0.8 | 91.5 | 1 |
| Water Heater Gas | 9 | 3.0 | 27.0 | 1 |
| Furrion Stereo | 10 | 2.0 | 20.0 | 1 |
| Chair Heater | 10 | 2.0 | 20.0 | 1 |
| Awning Light | 9 | 2.0 | 18.0 | 1 |
| Kitchen Fan | 13 | 0.5 | 6.5 | 1 |
| Water Pump | 45 | 0.1 | 4.5 | 0.75 |
| Kitchen Light | 3 | 0.5 | 1.5 | 1 |
| Awning | 38 | 0.002 | 0.1 | 1 |
| Tongue Jack | 96 | 0.0004 | 0.0 | 1 |
| Slideout | 72 | 0.0004 | 0.0 | 1 |
| Stabilizer jacks | 40 | 0.0004 | 0.0 | 1 |
| Chair Vibrate | 15 | 0.0 | 0.0 | 0 |
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| | | Off Grid Wh/day | 4,452 |
I concluded that three 280 Ah batteries could get me two days off grid and that 800 W of solar could extend it up to 5 days. If we needed more energy than that then I could connect the generator and charge the battery at up to 90 A. I would need to run the generator for 4 hrs per day to completely make up one days consumption. I didn't want to do this so I only use the generator for backup.
I did look at buying a bigger generator or buying a second small one and connecting them in parallel, but since the charger can only put out 120 A that was only buying me an additional 30 A.
Once I knew how much battery and solar I needed I could finalize my design. The hand drawn schematic below is my original design for the system. With this design I could start with one battery and attach up to three. If I decided I needed a fourth battery I would need to add bus bar capacity.
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| Original expandable electrical system design |
I selected a Victron inverter/charger. This is the heart of the system. The trailer was set up for an inverter to power some of the outlets. I wanted to be able to run everything and so was not able to take advantage of the prep work done by the manufacturer. The Victron passes through up to 50 A of shore power and automatically switches to inverter power is shore power drops off. It can assist if shore power voltage drops or if loads such as an AC exceed the capacity of the generator. There are also all of the gizmo wizardry that Victron does that makes the whole system easy to use.
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Final schematic of the electrical system.
The breaker panel and the tongue junction box (Jiggy Box)
were my tie in points to the rest of the electrical system. |
We decided to do the installation under the dinette at the rear of the trailer. I played with the layout a bit and came up with a plan.
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Component layout for placing the major components under the dinette.
Driver side is on the right, rear of the trailer is at the top, passenger side is on the left. |
I was finally comfortable enough with my plan to start ordering parts.
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| Shrink tube, battery switch, cable reducers, fuse holder bus bars and a DC breaker |
The "chaotic corner" at the driver side rear of the trailer. Shore power comes in here and the cable TV box is here. Many locations have a breaker for the shore power, but we had been to enough that did not that I added a breaker between the shore power outlet and the inverter/charger.
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| The chaotic corner and the driver side battery. |
At the top is the breaker for the DC loads in the trailer. Below that is the Cerbo GX which integrates the inverter/charger, solar charge controller and battery monitor. Below that on the floor is the battery monitor. The wall on the right has the back of the inverter/charger control panel.
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| Inside the chaotic corner |
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| The shore power breaker |
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The inverter/charger connections.
AC on the left, DC on the right, two data cable and a big ground cable. |
The control panel for the inverter/charger has a switch for On/Off /Charger Only and a know to set the maximum allowable shore power.
We leave the inverter/charger on all the time, mostly so we don't have to reset the clock on the microwave every time we move.
The input current limit is useful when we are connected to 30 A instead of 50 A and when I want to charge with the generator. I have a 2500 W inverter generator and the output voltage drops above 13 A.
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| Inverter/charger control panel |
The inverter/charger is located on the rear wall of the trailer. I raised it to be able to run cables under it.
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| Inverter/charger. The heart of the system. |
The picture below was taken before I added the third battery. There are two more 4/0 cables under the inverter/charger now.
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| Under the inverter/charger. |
The cable for the two batteries on the passenger side. I installed a raised floor over these to reclaim the storage area.
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| Battery cable for the passenger side batteries. |
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| Passenger side batteries |
The final step was to connect the new batteries at the rear of the trailer to the junction box at the front of the trailer that the battery originally connected two. This required running two 4/0 cables through the underbelly. I used 4/0 to keep the voltage drop to a minimum and had to reduce them to 4 gage wire to land them in the junction box.
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| No batteries on the tongue. |
The positive battery cable is the red one on the left. The negative battery cable is on the right. It loops under the junction box and the reducing block is visible.
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| The junction box on the tongue. |
The wiring for the solar panels is 10 gage so the maximum current I can put through is 30 A. This limited me to 5 panels maximum if they are all wired in parallel. This is also the maximum the roof can physically fit. I currently have capacity for one more panel (top right in the picture below). I like having room on the roof to walk so I will leave the fifth panel off unless it proves to be necessary.
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| 800 W of solar panels |
I used a 4 way splitter and secured the cables using Dicor sealant. Note the images below are taken from the opposite direction as the one above.
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| 4 way parallel splitter |
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| Cable for rear passenger panel |
The Cerbo GX integrates the inverter/charger, battery monitor and solar charge controller. This allows for an easy to read display of where your power is coming from and going to. This can be accessed locally through WiFi, either by connecting the Cerbo GX to an existing WiFi network or by using the build in WiFi server. The same date can be accessed over the internet using Victron's VRM, which remarkably is free. Both of these are accessible by a laptop computer or on a mobile device. You can also buy a stand alone screen that mounts in the trailer, but I didn't.
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| VRM dispay on a laptop |
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| Local network display on a laptop |
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| VRM display on an iPhone |
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| Local network display on an iPhone |
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