More direct solar energy falls on the Earth in one hour than the entire human race consumes in a year. Here’s how we’re using RV solar panels to capture this unlimited power source to energize our travels.
Table of contents
- Using Solar Power on RVs
- RV Electrical System Upgrade
- The Batteries
- The RV Solar Panels
- Inverter, Charge Controllers, and the Brains
- Cost of the System?
- Why do we need such a large RV Solar System?
- Charging an Electric Car with Solar Power
- What’s Next?
Using Solar Power on RVs
Many homeowners and RVers like us have been using solar power for years. Solar photovoltaic arrays allow you to take all that free energy that falls on your roof every day and turn it into usable electricity and we have been primarily living off this free energy for over two years.
We dove into RV solar energy with a cost effective power system to see how we liked it, and we have fallen in love with its silent generation that enables us to easily live wherever we want as we are the power plant.
We decided to take our solar electric to the next level.
We’re going to be squeezing out as much power as we can get off this 33 foot RV with the latest technology and try some things with an off-grid system we never thought possible. Join us as we build our Ultimate Off-Grid RV Solar System!
WATCH THE VIDEO:
RV Electrical System Upgrade
With Tom being an electrical engineer and a do-it-yourselfer, he designed and built the whole system himself – so we had no labor costs for both system installs.
For this build we are completely replacing the whole previous system with upgraded technology.
RV solar systems may seem complex, but if you break it down off-grid solar systems consist only of a few major components. In this article, we will be covering an overview of the components, and you can check out the full schematic below and join our newsletter to get notified about future posts about the new system.
If the schematic seems complicated, don’t worry. We are going to break things down to their basic components.
At the heart of every solar system is the battery which stores the energy for nighttime and cloudy day use. (Every RV solar system is essentially an RV solar battery charger.) We installed a much larger battery bank, 8 Battle Born 12V 100Ah GC2 Lithium-ion batteries.
Our first RV solar system was built with a Tesla Model S car battery at its heart. This worked very well but was a complex build as Tom had to design the whole battery management system himself to make sure the battery was safe.
Tesla modules are a lithium NCA chemistry and pack a lot of energy into very little weight, but have the drawback that if anything gets out of spec with the battery they are prone to catch fire.
While we had built a safe system and never had problems, it was much easier to install Battle Born Batteries for the upgrade. These batteries have all the protections built in so they can be hooked up like normal batteries. We also already had 5 batteries from our previous project, the Go North Expedition and this was a perfect opportunity to use them.
The Tesla module is on the right and Battle Born on the left, a few cells of what are in the Battle Born battery sit in front of it.
One of the biggest benefits of lithium batteries is that they can be installed anywhere in any direction. For this build we decided to install them upside down. Years ago we had removed the black tank from our RV and installed a composting toilet. When we did that we were thinking that we might use the space where the black tank was for batteries in the future, so that’s exactly what we decided to do.
We built custom brackets to hang the batteries upside down where the black tank used to be and wired them all up with the terminals facing down.
We wired them in a 24-Volt configuration because with the amount of solar we would be installing we needed a higher voltage system to handle the current. With larger systems we always recommend building at least a 24-volt setup and possibly even 48-volt.
Batteries all wired up upside down and ready to be connected to equipment
The RV Solar Panels
The solar panels generate the power from the sunlight that is used to charge the batteries. In this build we are going to use the latest tech mobile application solar panels to more than double our power production from our first build.
When we were starting to think about a solar upgrade we found out about Battle Born Batteries latest solar product offerings and were happy to hop on board to try them out.
*Battle Born Solar Panels are currently only available through their Bundle Packages.
We decided to install their 230 watt panels that come in two shapes and sizes, the BBS230A and BBS230B panels.
We installed 10 panels on the roof of the RV, and because of the cool peel-and-stick design, we also decided to install 2 more panels on the front cap of the RV!
The panels on the front cap won’t perform as well as the roof solar most of the year, but come wintertime is where they really start pulling their weight. As a full-time RVer, we use our RV year round and solar always struggles in the low sun angles and short days of winter. Continue reading to find out how they have performed!
All 10 Panels on the rooftop, the 4 BBS230A are on the left and the 6 BBS230B are on the right.
Two additional BBS230A panels installed on the front cap of the fifth wheel.
What makes these RV Solar Panels special?
These panels are unique because they are high-efficiency mono-crystalline cells in a flexible stick down package.
Let’s break this down:
HIGH-EFFICIENCY. These panels are 19% efficient vs. our previous panels’ 14% efficiency, meaning we get more power out of the same space! This is especially great when you’re working with limited space – like an rv roof.
FLEXIBLE PANELS. In the past we have been leary of flexible panels because they tend to have short lives due to thermochemical stresses internal to the panels, but these panels have solved that.
The Battle Born Solar Panels utilize a special grid structure instead of bus bars that allows for considerable movement without breaking. This structure also puts so many points of contact on the solar cell that if it cracks there is minimal power loss.
electing RV solar panels can be tricky depending on your needs, but we found that these panels checked a lot of boxes for our RV solar system.
First, these are very lightweight RV solar panels. This is huge because weight is such a limiting factor in many RV solar builds.
Second, the ease of installation and no holes to be drilled in the RV’s roof eliminating leak points.
Third, durability. These panels are also military grade and should take the beating that many RV solar panels take because of branches, and vibrations of just going down the road.
Now these panels do have their drawbacks as well, the biggest of which is heat dissipation. Hot solar panels preform worse, and being stuck to the roof with no airflow these can get very hot. They can also dissipate that heat into the RV making your living space hotter.
The second biggest drawback is the cost as these panels are more expensive than a similar glass solar panel alternative or even some other flexible competitors. As with any system, the drawbacks must be weighed against the positives for your situation.
As we test the system more, we will elaborate on the pros and cons of these panels, but so far we have been loving their look and their performance!
We wired all the panels in a series parallel configuration and utilized a special combiner box on the roof that allowed us to wire them in three separate circuits. From here the wires ran down to the electronics.
Inverter, Charge Controllers, and the Brains
Solar panels cannot be connected to the batteries directly and need a special charge controller installed between them and the batteries.
This is because the panels power output will differ from what the RV batteries require for charging and this device converts it to the appropriate level and optimizes solar panel efficiency.
With our Ultimate RV Solar install having so much solar power, we needed to use three separate charge controllers to handle the load and to make the system more efficient.
We installed 3 Victron Smart Solar MPPT 100|50 charge controllers.
Partial shading and different lighting conditions on some panels and not others – like we have on the front cap panel set – can negatively impact the performance of other panels on the same charge controller, but keeping them on their own controller prevents this making the system more efficient.
Connected to the battery are the RVs loads and typically an Inverter to convert the DC battery power to typical residential AC power.
Our past install utilized a Victron 3000VA inverter and for this build we upsized it to a 5000Va Unit. (VA stands for Volt Amps and is a unit of power used for alternating current, similar to watts) This larger inverter can provide a lot of power to be able to run multiple large appliances at once including the air conditioner and really helps to make it feel like we are hooked up to the grid all the time. We can run the microwave and instant pot and at the same time, no problem!
After installing the inverter there were only a handful of components left to install. First the DC-DC converter that changes the 24 volts of this battery bank to 12 volts that the RV’s DC appliances and lights use. Our first install was a 24 volt system so this was not a change for us and we were able to re-use the same Victron Orion converter we had used before.
We have been using the Victron Orion 40 AMP converter and we re-used it for this system Lastly, we installed components that would monitor the system and allow us make changes to its performance remotely. A battery monitor is essential in an ultimate off-grid system as it gives an accurate reading of the state of charge of the batteries
We used the Victron BMV712 battery monitor. The BMV712 is a 2-part meter that includes a shunt installed on the negative lead of the power system and this internal display unit installed in the RV. For our Ultimate System we also installed a computer called the Octo GX that is designed to communicate with the inverter, charge controllers, and battery monitor to wirelessly communicate the systems data with an online portal.
This allows us to see how the system is functioning on a phone or computer as it shows solar energy, battery state of charge, AC and DC power and how it is flowing.
It also sends this data to the Victron VRM Portal that allows us to log into the system remotely and see its performance real time. Here we are able to easily make programming changes to the system – we will be sharing what we utilized this for in an upcoming articles and videos.
The Octo GX unit we are using as the brains of the system, it has no display but connects wirelessly to a phone or computer Below you will find a summary of the changes we made. Note the weights of the system components as this was a huge factor for us. We only had about 150lbs additional weight we would allow for this system and when all was said and done we came out only around 110 lbs heavier overall which we are thrilled with since we increased capacity 3X on both RV solar panels and batteries!
Click here to see the list of system components:
We have been operating this system since June 2020 and things have been working great.
We have traveled with this system over 3000 miles and all the connections to the batteries and electronics are still tight and all the panels are staying well adhered so were very happy about that!
With the larger inverter we have been able to run multiple large loads, like cooking appliances, hair dryers and even the air conditioner we have run a bit on sunny days, without worrying about overloading it.
It really feels like we are living with the RV hooked up to shore power all the time. We are also loving having the system connected online so we can monitor its performance.
Data Data Data! This is the dashboard for the Victron VRM portal that the Octo GX sends data to and can be accessed online. We will be sharing lots more about the performance of the system in the future. Overall, we are seeing daily power output in full sun between 1600 and 1800 Watts but have seen peaks upwards of 2300 Watts.
A lot of that power loss we believe is due to heat on the panels and will elaborate of this in a future post.
Front Panel Performance in Summer & Winter
What about those front solar panels?
While at first glance they may seem impractical, there is a method to our madness. You see, as full-time RVers, we chase 70 degrees and stay in our RV year-round. In the wintertime, the sun’s angle is much lower in the sky. The steep angle of the front camp, while a disadvantage in the summertime, is an advantage in the winter.
Let’s look at some numbers:
|Front Panels||200W/460W = 43.5%||340W/460W = 73.9%||+30.4%|
|Roof Panels||1500W/2300W = 65.2%||1020W/2300W = 44.3%||-20.9%|
|Total System||1700W/2760W = 61.6%||1360W/2760W = 49.3%||-12.6%|
In both instances, the nose of the RV was pointed directly south. One was in Michigan (summer) and one was in Arizona (winter).
Based on the data above, we see a few interesting things happening.
First, the winter peak performance of the front panels increased 30%!
Second, the roof panel performance decreases by 20%.
Third, the performance percentage of the front panels in winter exceeds the peak performance of the roof panels in summer. This is because while we have more direct and powerful sunlight in summer, the temperatures are higher – the panels can get upwards of 160 degrees F! This decreases the overall performance of the panels in summer.
More data and analyses coming soon!
The best thing about the panels, however, is the weight and how that enabled us to put so much power on this RV’s roof. Before finding these panels, we didn’t want to use flexible lightweight RV solar panels but now we are confident they will last. We have been able to max out the generation capacity off this 32 foot RV’s roof, hence why this is our Ultimate RV Off-Grid Solar install.
Cost of the System?
So a huge question we get asked is: what did it cost? Considering we did all the work ourselves the components for this system would come in around $17,000 retail.
This may seem like a lot to spend on a power system in an RV, but there are a lot of factors to consider in the investment so why might you do this.
For us, this is our home and we have no plans to leave the RV. So to have the amazing benefits that come along with not having to worry about power anywhere we go is huge for us. Solar power has changed our mobile lifestyle for the better and we couldn’t imagine not having it now.
We also have property that does not have power pulled to it. To get the utility to pull power from the road would cost more than $20,000 – so that right there makes it worth it! We can have power on our off-grid spot and take it with us, too!
Why do we need such a large RV Solar System?
Well, we hate running our generator. We love the silence and ease of this system, and we love not worrying about having enough power or battery capacity.
That said, this system is oversized for our average daily power need, but this really helps with multiple cloudy days in a row or the shoulder and winter seasons when we don’t get as much sun.
The system is also large enough that on very hot summer days we can run the air conditioner on solar power to break the heat – a huge plus!
The trick is that when we don’t have a big electrical load and the batteries get fully charged that the power goes unused…unless we find something else to store it in.
Charging an Electric Car with Solar Power
We decided to dump the excess solar energy into a plug-in hybrid/electric car. Read all about how we did it here.
If you’re interested in the specific details of this particular installation, watch out on our YouTube channel for the next video in the series where we dive deep into what an install like this takes.
Also, join our newsletter below to learn when we post more about this system, as we are not done playing and fully testing it out yet! We’ve got lots more data and performance specs to share.