Solar Rover, Part 2: The Install

As discussed in Part 1, we decided to do our own solar install rather than paying someone else to do it. Apart from saving a good chunk of money, this gave us a much better understanding of how the system works, which hopefully means it’ll be easier for us to troubleshoot in the future if we run into problems. It was by far the most involved DIY project we’ve done, but I’m happy (and relieved) to report it was a success!

Given the large amount of work involved in the project, I broke our solar install into a few different parts:

  1. Route the solar wires from Rover’s roof down to a storage compartment near the battery bank.
  2. Mount the solar panels on the roof and connect them to the aforementioned roof wires.
  3. Install the battery monitor and solar remote panel in the kitchen and route the wires to the storage compartment.
  4. Mount the solar controller, breaker, and switch in the compartment we ran the roof wire to.
  5. Connect the solar controller and battery monitor to the existing battery bank.

Unlike some of our other DIY blog posts, this one will be a bit more “high level”, showing what we did in general but not necessarily detailing every single step. Since every RV is different, our steps probably won’t work for everyone, and would make this article extraordinarily long! Hopefully the overview will provide enough detail to help other DIYers get started on their own installs.

Part of "The Plan"

Part of “The Plan”

1. Route Wires From Roof

Even though this turned out to be one of the less time-consuming steps, it was the one that gave us the most anxiety. Drilling a hole in Rover’s roof was one of those “measure 15 times, cut once” moments. Since our refrigerator is in a floor-to-ceiling cabinet with access to a wire run along the side of the RV, we decided to try to drop a wire down from the roof next to the refrigerator.

Fortunately we had photos and videos from our visit to watch Rover being built which turned out to be immensely helpful. We were able to figure out that even though we didn’t have a propane refrigerator, Tiffin still installed a vent duct (see blue arrow in photo below) in the insulation above the refrigerator for one—they just didn’t cut through the roof or install a roof vent:

Rover's roof construction

Rover’s roof construction

By drilling through the roof in the right spot, we avoided hitting any wires or metal plating, and didn’t have to drill through a few inches of styrofoam insulation. It was a bit nerve-racking, but our hole was as close to perfectly placed as we could have hoped for:

After a nerve-racking drilling session, we confirmed that our hole was in the right spot!

After a nerve-racking drilling session, we confirmed that our hole was in the right spot!

After drilling through the roof fiberglass with a 1-inch hole saw, we were in the four-inch tall (or so) unused propane vent. Since the vent was unused, we also had to drill through the interior ceiling of the RV, directly above the refrigerator. Fortunately a long 3/4-inch spade drill bit was able to reach the ceiling and complete the cut. The last part was tricky: pushing the dual #4 solar cable through the roof hole and then the ceiling hole, and finally getting it to bend the right direction around the top of the refrigerator.

Wire successfully routed through the roof and ceiling.

Wire successfully routed through the roof and ceiling.

After several frustrating failed attempts, the wire finally went the right direction! It was then a simple matter of grabbing it from the refrigerator access panel on the side of the RV. In the photo below, the solar wire is right next to the back of the refrigerator:

Grabbing the solar wire via the refrigerator access panel outside the RV.

Grabbing the solar wire via the refrigerator access panel outside the RV.

From the refrigerator access panel we could push the wire into the wire chase that runs the length of the RV behind various cabinets and drawers. We removed all our kitchen drawers and fed the wires along the inside wall of the RV behind the kitchen cabinets:

Routing the wires behind the kitchen cabinets.

Routing the wires behind the kitchen cabinets.

The last step was to drill a hole up from the storage compartment next to our battery bank into the kitchen floor behind the cabinets. Again, measure many times, cut once!

Routing the solar wires through a new hole into a storage compartment.

Routing the solar wires through a new hole into a storage compartment.

After pushing the solar wire through the new hole in the kitchen floor, we finally had it where we needed it—in the storage compartment where the solar controller would be mounted. Whew!

From the roof to the storage compartment.

From the roof to the storage compartment.

We had one last step to complete before calling it a day. Back on the roof, we fed the rest of the solar wire through our holes to the storage compartment, saving just a bit to connect to the solar combiner box. Each solar panel will connect into the combiner box, and the big solar wires we just ran will carry the current down to the solar controller. We followed AMSolar’s video tutorial on installing the combiner box and it went pretty smoothly. With lots of Dicor lap sealant around the box and inside the hole we drilled, we should have a nice water-tight seal.

Combiner box mounted on roof and wires attached.

Combiner box mounted on roof and wires attached.

2. Mount and Connect Solar Panels

Mounting and connecting the solar panels was one of the more straightforward but time consuming parts of the project. Since this part is pretty much the same for everyone (unlike the wire routing described above), AMSolar has it documented perfectly on paper and in video tutorials.

As shipped, the panels are just mounted in rectangular aluminum frames. To mount them on the roof it’s first necessary to install mount adapters (via bolts and nuts) and feet (via plastic knobs). It’s very simple and AMSolar’s Installing the Rocker Foot Mounts to a Solar Panel video walks through the step-by-step process.

Installing the mount adapters.

Installing the mount adapters.

Next comes connecting the short output wires from the panel to the long rooftop wire supplied by AMSolar. The required cutting, stripping, and crimping are all explained in the Installing the Output Cable to a Solar Panel video, as well as the final step of using a heat gun to seal the heat-shrink glue connectors to the wires.

Connecting the panel's output wires to our rooftop wires.

Connecting the panel’s output wires to our rooftop wires.

Our first attempt at this failed as our small wire crimper just wasn’t up to the task. After crimping, we gave a good tug to ensure the connection was solid—but it wasn’t. We crimped enough to make the yellow connector unsalvageable, but not enough to hold the wire securely. We had to cut the connector off, make a Home Depot run to buy new heat-shrink connectors, and borrow a heavy duty crimper from a friend (thanks Warren!) for the rest of our work. With that lesson learned, the rest went very smoothly.

The next step was mounting the panel to the roof. Rather than using screws (we didn’t really want another 24 holes in our roof) we used the 3M VHB tape AMSolar has built-into the panel feet. The tape creates an extraordinarily strong bond which should last forever. This time we followed the Sticking the Panel to the Roof video, paying special attention to the roof preparation steps. We thoroughly cleaned the mounting locations on the roof with alcohol, and since it was a cool day, warmed the roof surface briefly with the heat gun before sticking the first panel down.

First panel mounted to the roof.

First panel mounted to the roof.

We used the provided sticky pads and cable ties to secure the rooftop wire in several places along its route to the combiner box, again cleaning the roof and adding some heat before sticking the pads. After routing the cable for the first panel we realized just in time that we hadn’t left enough slack near the panel to allow us to tilt the panel up! We’d purchased tilt bars to let us point the panels towards the sun, so it was lucky we caught this oversight before cutting the wire and connecting it to the combiner box! We fed a little bit of extra wire back to the panel and learned another lesson!

Rooftop solar cable secured in place.

Rooftop solar cable secured in place.

With the wire now in the right place we cut the other end to the right length and connected it to the combiner box, following the Installing the Roof C Box video (wiring the panels start at around the 7-minute mark):

First panel connected to the combiner box.

First panel connected to the combiner box.

We mounted a second panel to the roof, but called it a day before wiring it into the combiner box. In fact, with one panel completely finished, we moved on to the other parts of the installation instead of continuing with more panels. I wanted to get everything set up and tested with one panel first, then add each additional panel one at a time to ensure they were all working and wired correctly.

Two panels mounted, one panel wired.

Two panels mounted, one panel wired.

3. Install Remote Monitor

The BlueSky IPN ProRemote serves two functions. It allows for remote monitoring and configuration of the solar controller, and it is a high accuracy battery monitor. Rover came with a very basic battery monitor that reports the surface voltage of the batteries, which can then be compared to a chart (e.g. 12.2 volts means the batteries are about 60% charged) but that’s considered a very unreliable method of determining capacity. The new monitor measures all energy going into and out of the battery to report exactly how much remains. For example, if a 400 amp-hour battery bank has had 200 amps drawn out (say, by the refrigerator and lights) and 100 amps put in (by the solar panels), it can report that the battery is 75% charged.

Our first step was to pick a location for the monitor. Following the example of others, we placed it with our other controls on the wall adjacent to the refrigerator:

Cutting a hole in the kitchen for the remote monitor and wires.

Cutting a hole in the kitchen for the remote monitor and wires.

The monitor requires two wires: one goes to the solar controller to allow communication and configuration, and the other goes to the battery bank for the battery monitor function. We taped the wires together and dropped them into the space between the wall and refrigerator. Moving outside, we were able to grab the wires through the refrigerator access panel and route them behind the kitchen cabinets and down into the storage compartment in the same way we routed the roof solar wire. After that it was a simple matter of mounting the remote panel:

Remote monitor panel installed.

Remote monitor panel installed.

4. Mounting the Solar Controller

The BlueSky SB3024iL MPPT controller is the brain of the system. It takes the energy coming from the panels and modifies the voltage and amperage to charge the batteries. Our goal was to install it close to the batteries, so we chose the first storage compartment behind our entry stairs. The four batteries are located under the first inside step:

The solar controller will be installed right next to the existing batteries.

The solar controller will be installed right next to the existing batteries.

The center of the compartment wall already had a pre-wire setup for an outdoor TV (which we don’t have) so we first had to move those outlets and wires up much higher on the wall to make room for the solar gear. Then I cut out outlines of the new components to figure out where to install them in the compartment (I like planning things visually).

Deciding how to arrange the components.

Deciding how to arrange the components.

Once the equipment was mounted it was time to hook up the wires, with another piece of specialized and borrowed equipment—a hammer lug crimper tool. This, along with a heavy metal mallet, crimps the lug connector to the end of the wire. Since I had never done this before I was glad to have help!

Installing lug ring connectors on the cables.

Installing lug ring connectors on the cables.

Our first attempt turned out pretty good (photo below), and for the rest we stripped a bit less insulation to make it perfect. All the connections then got heat-shrink insulation around them for a tidy and water-tight seal.

First two lugs attached.

First two lugs attached.

With everything wired up in the compartment (photo below), all that is left is to arrange the wires and secure them to the wall with some fasteners to keep everything nice and neat.

Cables attached but not yet secured.

Cables attached but not yet secured.

5. Connecting to the Batteries

The last step, and one that made me a bit nervous, was connecting everything to our battery bank. The battery monitor requires installation of a shunt, a small metal block with two connectors. All the electricity runs through the shunt, and with a battery monitor cable on each end of it, it can tell how much energy is flowing through. Fitting the shunt in our battery compartment was a very tight fit, but we made it work.

Many new wires to the batteries!

Many new wires to the batteries!

With everything wired up we turned on the system and saw 3.6 amps of power coming in from our one connected solar panel! All that was left was to install the rest of the panels.

Finishing the Panel Installs

Over the next few days we worked more on the panel installs, getting better and faster with each successive panel. When we were done, we had all six wired into the combiner box:

20151116-IMG_5146

All six panels wired into the combiner box.

We closed up the box and finished securing the wires from the six panels. One panel would be mounted right over the combiner box, providing an additional layer of weather protection.

20151116-IMG_5149

The finished combiner box and secured panel wires.

We had all six panels securely mounted to the roof, and started running our final tests. In the afternoon in mid-November in Northern Virginia we saw about 16 amps of power coming into the batteries from the panels. Very cool to see, but not exactly amazing.

20151116-IMG_5153

Six panels mounted and connected.

Ah, but once we tilted the panels towards the sun, we saw double the power: a full 32 amps, and sometimes a little more, coming in! Since our controller can handle 40 amps maximum, this was more like what we expected, especially given the sun’s low angle in the sky. In the summer when the sun is more overhead we should see even more power.

20151116-IMG_5155

Tilting the panels toward the sun doubled their power output.

Besides being able to see how much power we’re generating from the sun (32.3 amps in the photo below), the remote/battery monitor has also been really helpful in figuring out what’s using up our power. With everything in the RV turned off (or so we thought), we were still using over 10 amps of power! Most of it appears to be due to devices that appear to be turned off but are really in “standby” mode, like our TVs, Xbox, or printer. By turning off the circuit breakers to those devices we got our “all off” usage down to 0.4 amps. Being aware of how much power we’re using will go a long way to making it through the night (and day) just on solar power.

20151116-IMG_5159

The remote controller/battery monitor tells us how much power we’re generating and how much we’re consuming.

With the project finally wrapped up, after a month of (on-and-off) work, it was time for a little celebration and relaxation! Well, as soon as Kathie un-tilts all the panels back to flat/travel mode that is!

20151116-IMG_5162

Finally finished. Kathie says “hooray”!

Michael Fischer

After a high-tech career spanning software development and systems administration to leading hundreds of engineers across cities and continents, I'm now slowing things down a bit. Traveling full-time in an RV with my awesome wife Kathie and our two big dogs Max and Opie, I'm now pursuing smaller personal software projects while seeing North America up close.

24 Comments

  1. Kevin Hughes   •  

    I really enjoyed reading about this project! Nice job!. My only concern is with the panel attachment. I hope the adhesive does not weaken over time. I am thinking about higher wind speeds while the panels are angled up.

    • Mike   •     Author

      I was a little skeptical at first, but AMSolar has been doing nothing but RV Solar for years with these taped feet. They say they’ve had zero problems with panels coming loose. The 3M web site (for the VHB tape) says: “Once materials are joined with 3M™ VHB™ Tape a virtually indestructible “weld” is created.”

  2. Bruce   •  

    Ordering a Tiffin 32SA and plan to do lots of boondocking and state/national parks without power hookups, so you have put together a system that is pretty much what I had in mind. Why did you go with 6-100w panels instead of 4-160w ?

    Really nice explanation of your install…thanks for sharing.

    • Mike   •     Author

      Bruce, the four 160W panels would have been less work (and more watts) but due to their larger size the front pair would be at high risk of shadows from the front air conditioner. The 100W panels fit well up there and don’t overlap the A/C area at all. I think Tiffin now offers a solar pre-wire package… do you know what size wire they install? -Mike

      • Bruce   •  

        That’s what I figured with the larger panels…I’d still like to figure out a way to make that work, though. We’re planning to order with the solar pre-wire done but it’s anyone’s guess as to the size of wire they use…I get a different answer every time I ask that question. I have yet to contact the factory, but I bet the wire is smaller than what is really needed. If it’s too small, I’ll have to wire the panels in series, I guess, to get the voltage up and the amps down.

  3. Anne P   •  

    Thanks, Mike. I’m not quite at the point of installing roof panels, but have bookmarked your very clear explanation and pictures for future reference.

  4. Laura   •  

    Congratulations on finishing this daunting project and thank you so much for the detailed instructions. I expect we’ll eventually be following your lead and these instructions will be so valuable. Please keep us updated on how it all works out! Happy travels!

    • Mike   •     Author

      Well done! I agree the best part of doing something like this yourself is how much you learn in the process. I’m no expert, but I feel that I’m a lot more solar and RV electrical savvy now compared to when I started on this… -Mike

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  6. Bernie Gilles   •  

    Awesome play by play, I really enjoyed it and learned a lot! Thanks!

  7. Glenn Hubbers   •  

    Nice write-up, thanks!

    We installed the GoPower Extreme package on our 5th wheel trailer and began our journey only 1 month ago, so we are still learning about the limitations. What I’m finding is that I have a significant depletion of power overnight, to the point where I have little to no usable power in the morning till we get charged up by about 10 am. We end up having to boil water for coffee on the propane stove, which was NOT what we bought this system for!

    I’m not sure of the problem. Perhaps I’ve got a lot of phantom power losses to look into? Perhaps my three deep-cycle marine batteries are not enough? Perhaps if I added the tilting brackets I’d get more power earlier in the day?

    Just wondering what your experience is in terms of how much capacity you still have when the sun comes up, and any suggestions you might have for me to investigate the issues.

    • Mike   •     Author

      Glenn,

      Hopefully you installed a battery monitor with your system. If not, you should add one (like the TriMetric) right away! Using the battery monitor I saw that even with everything turned off I was still drawing around 16 amps constantly. Overnight that adds up! One at a time I turned off circuit breakers (e.g. for the TVs/Entertainment, for the GFI outlets, for the regular outlets, etc.) and watched the amps tick downward. The entertainment circuit was the worst… even with things turned off, they still had a significant “standby” load (two TVs, Xbox, AppleTV, WiFi Router, etc.). Once those circuits were off I was drawing around 3 amps. I also tested things like our fantastic fans, our furnace fans, etc. to see how much power each one draws. You should only expect to get around 5 hours of solar power per day during the winter, which means you’re using up your batteries the other 19 hours, so the lower you can make that background draw the better. If you can’t measure it (e.g. no battery monitor) you are flying blind. Hope this helps! -Mike

      • Glenn Hubbers   •  

        Thanks Mike, great recommendation and I’ll look into that.

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  9. Ed Bickford   •  

    Very nice job! Have you found it was worth the cost? I plan to do the same later this year after I have our new home built. I went to the RV Supershow in Tampa this past weekend and was fortunate to meet the National Sales manager for Tiffin who knows the product very well. We are sure we will buy either the 36LA or the new 36UA which they debuted at the show. I had a lot of questions for him including what was included in the Solar Prep and the wire size. It comes with #4 wire which is run from a box on the roof to the cabinet on the far left above the drivers seat. From there the wire runs down to the battery compartment.This was in the 36LA. If you want larger wire and custom order you can request it. He did tell me that #4 is adequate with the batteries they have and adding additional batteries could add significant weight. When you were routing the wire next to the refrigerator did you notice what was behind the panel under the refrigerator? I’m assuming it’s part of the propane system, just wish that refrigerator was closer to the floor for those of us that are vertically challenged.

    • Mike   •     Author

      Not bad… #4 is what we ran for our 600 W of panels in parallel (12 V). Under the refrigerator is the propane furnace, but we didn’t have to remove that panel. We had to get a step stool to reach the top of the fridge! So far we’re enjoying the solar, but it’ll take a while to decide if it’s worth the cost. The big slide on the 36UA looks interesting, we’ll be keeping an eye on it as it’s the first time Tiffin has ever done a full wall slide… -Mike

  10. Ed Bickford   •  

    I think we have decided on the UA as it has bunks which we will use for extra clothes and junk that we are struggling to get rid of. Grandkids may use them too. Would be interesting to know your normal usage TV, Computer etc. and how long you can boondock with the solar. I’m thinking of starting with a setup like yours until I see how it works for us. With the tax credit iI think the payback will be a year or less.

    • Mike   •     Author

      Our laptops are on pretty much all day, but use very little power. We often don’t watch any TV, but if we do it’s 1-2 hours per evening. We’ve been boondocking for over a week now, and we’ve found that we need about 30-60 minutes of generator first thing in the morning to give some bulk charge to the batteries, then the solar takes over for the rest of the day. By sunset we’re usually at 100% battery, by the time we go to bed we’re around 85%, and when we wake up we’re around 70%. Rinse, repeat.

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  12. Ed Bickford   •  

    Thanks for the info, that would definitely work for us. I guess the only way it would make sense to add more panels would be to add more battery. Hard to do unless you want to give up some storage space.

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  14. Joe Martinez   •  

    Just found your blog Mike after we made a decision to purchase our 31SA and I started to look for mods the community has done. You site has been tremendously helpful in our planning.

    We pick up our coach next week and I intend to document my mod and solar work as well so as to pay it forward. Thanks for the inspiration.

    • Mike   •     Author

      Congrats on the coach, I’m sure you are counting down the hours until you pick it up! Once you do the solar install I’d love to hear about it. The more different setups we can document, the better it’ll be for other folks (or me in the future ;-).

      -Mike

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