Solar 1.0
We always knew we that we wanted to add solar, go off-grid and simply be more self-sufficient. Bubbles was pre-wired for solar which meant that the wiring for a solar charge controller, battery monitor and external, portable panels was already in place. In theory, all we had to do was purchase our kit and plug it in. With an upcoming trek to Alaska, land of the midnight sun, we rationalized that we could live with our two recently installed 76Ah 12V AGM batteries and go to town on solar.
After much research and deliberation, we decided that we were going to use a Victron MPPT Smart Solar charge controller. The smart portion of the controller is the ability to be managed using a phone app over Bluetooth as well as network with other Victron devices. They are also very programmable, and being a techno-weenie, this appealed to me!
Our next key decision point was the type of solar panels. It made sense to have portable, external panels that could be moved around to follow the sun or work in shaded areas. We didn’t want to give up space in the back of the truck to traditional portable kits and opted for two SunPower based flexible panels. SunPower makes one of the most efficient solar cells on the market, and WindyNation had them in stock. These were affixed to plastic corrugated board providing strength and rigidity. So little was added to the the panels that we could store them in their original box.
Our next decision was with regards to the roof panels and we decided that rigid panels made the most sense. We shopped around, long and hard, and decided upon Renogy Eclipse 100W panels as these were the best value for money and performance. We estimated that we could fit a total of seven rigid panels on the roof (three on starboard and four on port) but by the time we ordered, only five were available for purchase in their US inventory, so we went with five. We figured that could later add the other panels. We had briefly considered setting up the panels in a 24V configuration but the simplicity of going 12V as well as having and odd number of panels kept us in 12V land.
We were in Texas long enough to order and receive the charge controller, flexible panels and a run of solar extension cords. We hooked everything up to the batteries and were good to go. We used our camp chairs as stands for the panels. This setup would do until we landed in Oregon and had time to tackle the real work on top of Bubbles.
DIY Solar Abridged Version
Here is the abridged version of what we used for our solar install.
- Victron 150/70 MPPT SmartSolar Charge Controller – the brains of the operation
- Victron SmartBattery Sense – sends the brains accurate voltage and temperature information
- WindyNation 100W SunPower Flexible Solar Panel – two
- 20′ 10AWG solar extension cable with MC4 connectors – to go from charge controller to solar panel(s)
- Solar MC4 Branch / Y-connector – to connect both flexible panels to extension cord
- BlueSea On/Off Switch – disconnects solar panels from the charge controller
- 80A DC Circuit Breaker – disconnects the charge controller from the 12V system/battery
- Renogy 100W Eclipse Monocrystalline Solar Panel – five
- AMSolar 35mm Rocker Feet – one set of four per panel and one extra set for the leading edge
- Sikaflex 221 – one 10oz tube to seal all the feet and zip tie pads
- Renogy 10 amp inline MC4 fuse – one per panel
- Ancor Marine 10AWG Duplex Wire 100′ – extra was used for solar extension cords for the portable panels
- Zip tie pads – one 100 pack
- Zip ties – one 100 pack
- VHB 4950 tape – 1 in by 5 yards
- 6 AWG wire red & black – 15′ of each for all the interconnects
- Renogy MC4 Connectors – 4 packs of five pairs
- Renogy MC4 Tool – useful for fully cinching down MC4 connectors, one set
- Bullet/SAE extension cords – cut in half to make SAE to MC4 adapters, four of these
- Ground bar kit – two, one for combining the positive solar wires and one for the negative/ground
- Combiner box – one in which both the bus bars will be mounted.
- Small wood board – for mounting charge controller and other electrical components inside locker
- Assorted heat-shrink tubing – for sealing connections
- Red and black electrical tape – for sealing connections and changing the color of SAE MC4 adapters
Solar 1.1 – Part 1
Planning and preparation were the most time consuming parts of our installation. Electrically, this was very straightforward. The solar panels get combined and feed into the on/off switch which feeds the PV inputs on the charge controller. The battery outputs of the charge controller feed into the circuit breaker and from there into the bus bars. The Smart Battery Sense is wired directly to one of the batteries and is affixed to the top case using the double-sided, thermal tape.
Once we had all parts on hand, we used the Renogy solar panel boxes to approximate the placement and fit of the panels. If the box fits, then the panel will fit. Next we had to prepare the roof for the panels. We used AM Solar 35mm rocker feet which, following our no holes policy, would be glued to the roof using the supplied 3M VHB tape. VHB tape requires a clean surface so we took Nemo and Bubbles to the spa. We then dispatched our lightest crew member onto the roof for additional cleaning starting with water, then cleaning spray and finally with rubbing alcohol. VHB tape has a very specific temperature and humidity range for full adhesion so we waited until the weather forecast was favorable.
As we were using AM Solar feet with Renogy panels, we had to drill new holes in the Renogy frames. Keeping the feet matched with each panel ensure that we would have consistent movement. We placed the assembled panel and feet on the roof and set each location. The front two panels had an extra set of feet on the front edge. As these bear the brunt of the wind shear, it is recommended to have an extra pair of feet on these. Once we were happy with the position, one person would lift the panel up and another would clean the roof one more time with rubbing alcohol. Then we would remove the backing and press the foot to the roof. This process was repeated, leaving the panel in place, for each foot on each panel. VHB tape achieves 50% adhesion after 20 minutes, 90% after 24 hours and 100% after 72 hours. By the time we had completed setting all of the panels, it was time to back around and remove the panels. and put them away.
Next, we used the Skiflex 221 to seal around the base of the feet. This protects the VHB tape from water incursion. Sikaflex is like a really sticky meringue and even looks like it. It gets a little messy but who is going to be looking that closely on the roof anyway?
Solar 1.1 – Part 2
While the feet cured, it was time to tackle the electrical stuff. As we had already been using the charge controller with the flexible panels, not much testing had to be done. With limited locker space we decided that it would be best to mount all of our solar stuff to a wood board and then attach the board to the interior divider of the locker. We found nice piece of craft plywood and mapped out the locations of the components e.g., charge controller, combiner box, on/off switch and circuit breaker. It was then a matter of mounting the components and then cutting 6 AWG wire to fit. Before going any further, the circuit breaker was tripped, and the switch turned to the off position.
We weren’t that familiar with the Zamp bullet/SAE connectors so we used the factory wired solar port as a reference to determine the positive and negative connections. Before making any connection we always double-checked polarity with our multi-meter just in case anything was miswired at the factory or by us.
With five roof and an the flexible panels, we needed at least six SAE to MC4 adapters. As commercial ones cost around $25 each, we decided to make our own using some SAE extension cords, cut in half and then attaching MC4 connectors. We used tape to reverse the colors of the wires on half of these to the polarity. The final cost ended up around $6 per adapter and we have an couple of extras.
Running new wires from the battery box solar port inside was as easy as advertised. The new 8 AWG from the front cap had the positive an negative labeled. The solar pre-wire run was color coded and labeled as well.
I needed assistance with a smaller family member to mount the solar board to the inside of the locker. Then it got really interesting as I climbed inside. In hindsight, removing propane tanks would have made accessing the locker much easier. This was the most finicky part as I connected the three solar panel runs into the combiner box and circuit breaker to the bus bars.
Solar 1.1 – Part 3
Once the feet had set for 72 hours, it was time to reassemble the roof. We placed the panels in their designated locations and attached the wingnuts. Out of an abundance of caution, we installed an inline 10amp fuse on each panel. Sending our lightest team member back on the roof, we laid out the bulk marine 10AWG duplex wire and mapped the paths to be as efficient as possible.
To secure the wires from moving, we used UV resistant zip ties attached to zip tie mounts/pads. As these would be load bearing, we replaced the pads’ tape with VHB tape. These too were sealed with Sikaflex 221. Once we had the wire lengths approximated, it was a matter of stripping the ends with wire cutters and attaching the MC4 connectors. About MC4 connectors, they can be crimped, carefully, with needle nose pliers or the wire cutters. A proper crimping tool can make the process easier and faster. MC4 connectors are also designed to be tightened only once. Removing them, such as if you accidentally reverse polarity usually damages internal components beyond reuse. Double-check your work before securing the connectors. I have gotten pretty adapt at hand tightening the connectors but the proper tool makes a difference and provide piece of mind that the connectors are secure.
Once everything was wired, we reset the circuit breaker to supply power the charge controller. Once online, we turned the solar panel disconnect switch to the on position and confirmed that the panels were delivering a charge. We then went inside and disabled the battery charger/converter ensuring that the only power being delivered to the 12V system was from the solar and batteries. We also plugged in our external panels to check but as the batteries were already full and there was ample sun, not much power was actually used the system. Eventually, the next few drive days confirmed everything was working as planned. We started with charge controller’s default settings but later switched to AM Solar’s suggested charging settings.
For the tilt bars, we purchased aluminum flat bars, cut them down to 1 foot lengths and drilled 1/4″ holes on either end. The AM Solar wingnut still attaches to the end closest to the panels and we added additional bolts and wing nuts to secure the tilt arm to the feet.
Solar 1.1 Reviewed
We have been very happy with the performance of our system. The back to back to back rainy days in Alaska demonstrated the shortcomings of our limited battery bank – nothing a future change to Lithium can’t solve!
The Renogy and SunPower panels performed really well. We didn’t tilt the panels as much as we expected, but that seemed to be more of a function of how often we moved. The only drawback to the lightweight flexible panels was their light weight! We were often in windy areas so the panels and camp chairs would be blown over. A rigid suitcase setup would not have had that issue and could even be left out overnight provided it was secured from theft. Our Victron charge controller provided enough information to calculate our daily power consumption and the Smart Battery Sense’s thermometer capability was an nice way to lazily check the outside temperature. It has to be also said that our addition of USB and 12V sockets as well as finding a 12V power supply for our HP laptops was a significant efficiency improvement over using the inverter.
At present, the only thing we would change, as far as the solar goes, would be to add that 6th panel for an even 600 watts on the roof.
Solar 2.0
After two summers in Alaska and Canada with many nights off grid, we can happily and confidently say that adding solar to our setup was worth every penny and effort.
If we had to do it over at this time, there are only a few small changes we would make.
WindyNation no longer sells SunPower flexible panels. Our panels still work but some of the connectors are suffering from unboxing, boxing and being blown over. We contacted WindyNation and they have said that repairing these should be easy. If we had to replace them at this time, we would go with Renogy Eclipse Lightweight Suitcase panels. These fold in half saving even more space and are designed for portability.
As we initially wanted to fully load our system with 1000 watts of panels (seven roof panels and three ground), we chose a Victron 150/70 controller. After two years of actual usage, a slightly smaller Victron 150/60 would have been sufficient and supports up to 860 watts of solar panels in a 12V configuration – ample for a 6 roof and 2 portable setup.
We still haven’t gotten around to adding the 6th roof panel. Currently our batteries need more help but that is a different story.
If you’re interested in doing a solar install yourself, we’ve cataloged all the bits and pieces in product links online on kit.co/AllThePlaces2Go/airstream-diy-solar
If you would like more detail or something explained, please don’t hesitate to contact us.
Stay tuned for more!
Article By Sean
