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Building a Rugged Overland Solar Off-Grid Power System

Building a Rugged Overland Solar Off-Grid Power System

Using technology to our advantage on the road is part of what makes RV travel fun and pleasant. We love having all the comforts of home, including power, no matter how far off the beaten path we decide to go. When it comes to overland adventures, reliability is king. Of course, we’re talking about electrical reliability. Having a system failure in the middle of nowhere can really put a damper on things. That’s why we built a robust overland solar electrical system for our off-grid truck camper adventures.

Join us as we take a closer look at it! 

What Goes Into an Off-Grid Power System? Overland RV Solar Power System With 12V Air Conditioning

Off-Grid Overland Solar Power

We have built lots of off-grid electrical systems over the years. We first started with a smaller system on our fifth wheel, which was powered by a Tesla battery. Then, we upgraded to a much larger system powered by Battle Born Batteries.

Through the iterations, we have figured out what works and what doesn’t. We believe our new truck camper build is robust and will provide all the power we need for our overland adventures. 

overland truck camper with solar panels on roof
Solar panels on our overland truck camper.

Each system we build is designed to fit the needs of what it’s powering. For our fifth wheel, the system is massive as it’s our primary home and runs a lot of power-hungry appliances and computers. In our truck camper, our power needs will be a bit lighter but still substantial. We’ll need reliable electricity for our computers, internet, and things like lights and our 12V air conditioner.  

We designed this system to be well-rounded. It can operate mostly on solar, but also backup to generator power as needed. Plus, we can charge the batteries while driving. In the following sections, we will break down each part of this solar build, why we selected the components, and detail what their purposes are.

The Schematic

For those who would like to follow along with the actual schematic of our build, I have provided it below. This schematic showcases all the new equipment that we installed but omits any existing wiring or wiring that was removed. Omitted sections include shore power connections, the generator, truck electrical connections, and the entire camper electrical AC and DC distribution systems. 

overland solar electric system schematic PNG
Here is a PNG image of the schematic. Depending on your device, this image may be scaled and too small to see. Download the PDF above for full resolution.

If you are also looking to see where you can find each of the products we used, here is a kit with links to each one for quick reference.

The Batteries – Battle Born Game Changer 3.0 

Lithium batteries are the backbone of all off-grid power systems, and our overland solar system is no different. Lithium lasts longer, has no off-gassing, is lighter, and can be deeply discharged. Compared to any lead battery type this is the clear choice for this build. 

Why Battle Born? 

Battle Born Batteries has been a partner of ours for a few years. We decided to use them again because we have always been highly satisfied with their products. To be clear, we would not have partnered with them again if we did not believe they built some of the best batteries available.

Don't Waste Your Money On Batteries - The Shocking Truth I Discovered When Testing RV Batteries

In our 4 years of using Battle Born Batteries, we have never had a problem and have not seen any noticeable performance degradation. We have installed other brands in the past on prior builds but had problems here and there. This time, we’re sticking with what we know works!  

540 Amp Hours 

We are trying out a new form factor of battery in this build called the GC3 or Game Changer 3.0. This battery uses the same type of cylindrical cells and BMS (Battery Management System) as Battle Born’s other batteries. The GC3, however, is a larger size and much different shape. The size and shape allowed us to easily install two of them in our camper, giving us ample energy storage in a small space.

Additionally, the batteries are in parallel to retain 12V in the RV. And the GC3 has screw holes and mounting brackets to secure the batteries down.  

Game Changer 3.0 Batteries
Two Game Changer 3.0 batteries were installed in parallel with a battery disconnect switch.

Distribution – Victron Lynx

Another new thing we are doing with this build is using the Victron Lynx shunt and distributor. This system replaces the battery monitors (BMV series) we have used in the past and busbars (typically Blue Sea Systems). We have been very impressed with how the Lynx works and how it makes wiring so much easier. 

Wiring was made to the Lynx with 4/0 cable, and we put a battery disconnect switch inline on the negative side. The Lynx shunt also includes a built-in fuse holder in which we installed a 500A ANL. The shunt communicates all power flow information to give us an accurate battery state of charge and real-time power usage.   

Victron Lynx Shunt and Distributor
The Victron Lynx system makes electrical wiring so much easier.

On the distributor side, four outputs are included, each having a MEGA fuse on the positive line. These fuses are monitored and have lights that indicate a blown fuse. If a fuse does blow, the Victron Lynx will communicate it to our system.        

Inverter/Charger – Victron Multiplus 3kVA 

The inverter we used in the system is a Victron 3kVA Multiplus. We have used this inverter in three previous builds and have had no problems with it.  

Inverters are an important component of all RV electrical systems. Learn why here: What Does an Inverter Do in an RV?

Victron Multiplus 3kVA
The Victron Multiplus is our go-to inverter.

The Multiplus offers great programmability and functionality and plenty of power for a rig this size. This unit also acts as a battery charger when shore power is connected or the generator is running. At 120A charging capacity, the inverter will take four hours to recharge the batteries from dead to full. 

Overland Solar Panels

To charge the batteries every day, we installed 495 watts of solar on the roof. Once again, we used Battle Born’s solar panels. They are rebranded Merlin solar panels and are some of the most rugged semi-flexible panels available. Overland solar systems need to be reliable, rugged, and lightweight, and these panels fit the bill.

These panels can also be secured without drilling holes in the roof, and they offer extreme weight savings, which makes sense for this truck camper build-out. To learn more about these panels, check out our article on flexible solar panels

semi-flexible solar panels
Battle Born’s semi-flexible solar panels are a rugged and reliable option for overland vehicles.

Controlling the Charge – Victron MPPT

For this system, we did something a bit different with the charge controllers. Because this is a smaller system, we decided to optimize the solar yield by installing one Victron MPPT charge controller for each panel. This enables each solar panel to operate as efficiently as possible, despite what the other panels are doing.  

Using “panel level optimizers” is a tactic for many shade-prone installations on homes. Research is being conducted on further improvement of panels with string-level optimization. Unfortunately, this technology is not available yet but could be great for smaller systems.  

Victron MPPT Solar Charge Controllers
Our three charge controllers – one for each solar panel on the roof.

Overland Truck Charging – DC-DC

An additional means of charging the batteries is using the truck while it’s running. Overland solar and off-grid power systems almost always have multiple means of power production. This increases reliability and allows the system to meet a variety of operational conditions and power demands.

To accomplish truck charging, we ran 6-gauge cables from the truck’s batteries to a 30 amp 12V DC-12V DC converter installed in the truck camper. From here, it connects to the distribution bus. 

The DC-DC charger modulates the power from the truck and limits the charge to 30A. This is critical to prevent overloading an alternator when connecting to lithium batteries. This is because they can charge at a much higher rate due to low internal resistance.  

30 amp 12V DC-12V DC converter
30 amp 12V DC-12V DC converter

The DC-DC charger also prevents the batteries from connecting to the vehicle when it’s not running. It is a programable unit, so we could set the input voltage high enough that it only operates when the truck is running.  

Electrical System Computer – Victron Cerbo GX

The last component in our system is the brains of the operation, the Victron Cerbo GX. This unit takes all the data from each of our other Victron components and aggregates it.

We then connected a display to this unit that shows us the operation of the whole power system. From this display, we can also make some programming changes and turn the inverter on and off.  

Victron Cerbo GX
Victron Cerbo GX
Solar system display
Solar System Display

12V RTX Air Conditioner 

While not part of the electrical system we installed the new Dometic RTX2000 12V air conditioner during the electrical build. We’ve been researching and writing about 12V air conditioners for a while, and now we are trying one out!

Curious to learn more about these battery-powered air conditioners? Read this: Is There Such a Thing as a 12V RV Air Conditioner?

First impressions have been great. The unit looks good on the roof and does what it’s supposed to do. This Dometic unit has no problem keeping the rig cool, but best of all, it draws very little power. In fact, it draws so little power that we’ve mostly run it on solar from the 495 watts on the roof. 

Dometic RTX2000 12V Air Conditioner
The Dometic RTX2000 looks great on our truck camper’s roof.

This unit does not require the inverter to run and has variable compressors and fans, so it operates relatively quietly.  

The air conditioner was not a direct fit in the existing vent hole and required a little cutting. The shroud it came with also did not work, so we needed to make a custom interior shroud. This unit was originally designed for semi-truck cabs, hence the weird size. It allowed drivers to have air conditioning while parked without running their engines.

For an overland solar-powered vehicle, having air conditioning is a luxury. But if it’s possible with a unit like this, why not! So far we have loved this 12V air conditioner but will be writing an update on it once we have some more time to test it out properly. 

Adventure Awaits

Overall this solar system turned out exactly as we wanted—midsized to meet most of our power needs without going too crazy. So far, it has primarily been used to run the air conditioner and our power tools while we complete the truck camper renovation. But soon, it will be powering a cross-country adventure!  

What Goes Into an Off-Grid Power System? Overland RV Solar Power System With 12V Air Conditioning

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Peter Rosado

Sunday 20th of February 2022

Thanks for all your content. I've rewatched this video a few times. I am trying to wrap my head around the concepts. Love the work you both have done. If I may, a silly question. I am hoping to do something like this in our Class C RV. When you implement these systems does the old school converter/charger have a function anymore? It does not seem so. If I understood correctly (I hope I did) on the AC side you go from the inverter straight to the "breaker panel" on the rig. Is it safe to presume the same applies for the 12v side of the house going to the 12v fuse panel? And the converter goes "away". Hope my question made sense. I have a progressive dynamics 4600 and from my vantage it seems it will be no longer needed. Many blessings in your travels

Mortons on the Move

Monday 14th of March 2022

Glad you are enjoying our content! Most of the time I just disable the charger but leave it in place. Many times it has its own breaker that you can just turn off. Its not bad to leave it in place as a backup in case the inverter ever dies. They do not charge lithium as well as the inverter charger but it will work. Ours is still in place, just disabled.

Dan

Saturday 13th of November 2021

Great post, thanks! Could you explain the VE direct cable connections from your 3 MPPTs to the Cerbo GX. There are only 3 connections on the Cerbo GX and with the Monitor also connected by VE direct cable…….?

Mortons on the Move

Monday 7th of March 2022

The Monitor is actually an HDMI out on the Cerbo and has a USB plug so they are all free. You can also convert the USB to VE direct if needed.

Mike D

Wednesday 27th of October 2021

What are you using for switching your accessories on and off ? I want to do a variation of your setup.

Mortons on the Move

Monday 7th of March 2022

Which accessories are you referring to? In the camper just standard switches, the truck has a set of Aux switches from the factory so we are just using those.

K Cruz

Tuesday 31st of August 2021

What do you rate this system at? 6,480 watts?

Mortons on the Move

Saturday 4th of September 2021

Depends on what you are rating. It's a 30 amp camper so the max wattage would be 3600watts. Under inverter, that's 2400 in this rig.

Perry Kosek

Monday 30th of August 2021

Hi Tom, (sorry Cait) I’ve grown to respect your electrical knowledge and component selection skills. I am a retired electrical engineer who has not been able to turn that mindset off. I suspect you will be no different. So here is my “engineering question” concerning the widely known heat dissipation problem with flexible solar panels. How has Merlin tackled this? I know they have added a tremendous amount of electrical cell connections and maybe thermal shut down. Is that it? I’m concerned about the additional expense of these panels and their longevity. BTW- Victron’s 30A dc-dc charger ? Keep up the great work! Perry

Mortons on the Move

Saturday 4th of September 2021

No thermal shutdown and they still have performance decline in extreme heat. As for longevity its those additional electrical connections with extra flex in them that allow expansion / contraction without breaking. We wrote an article all about flexible panels here https://mortonsonthemove.com/flexible-solar-panel-performance/

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