Solar System with Flexible Solar Panels in Escape RV
Many thanks Mark's share of his installation experience of 3pcs Lensun 80W Flexible Solar Panel on his Escape RV, the following is his installation details which also posted on https://www.escapeforum.org/forums
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https://www.lensunsolar.com/Flexible-solar-panel/Black-flexible-solar-panel
I completed my solar installation on my 2019 Escape 19 a couple weeks ago and had a chance to put it to use on a 6 day camping trip last week. I thought I would give an overview of my installation as some payback for all the good information I got from the forum. I also had great input from Jim Bennett, as well from my electronics wizard buddy who also helped me with the installation. Please note that this is the way I did it and not the only way, so if you prefer other installation equipment and methods better, go for it.
I chose to do my own solar installation specifically because I wanted to go with flush panels as:
• I am an aviation guy and I like the low profile aerodynamics of a flat panel over one stuck up in the wind,
• I like the fact that the panels are out of sight from the ground, which to me is more aesthetically pleasing, and
• the panels are less visible for theft and a lot more difficult to steal than ridged panels.
I ordered my trailer pre wired for solar, which greatly simplified the installation providing the MC4 connector on the roof and the wires running down to the driver’s side under seat area and from there to the battery. Note that I do not have an inverter.
The main components I used were purchased from Lensun.
1. 80W 12V Black Flexible Solar Panel. 37” x 21” Lensun panels. I chose this panel supplier as they had been already researched by Jim Bennett and used by many other forum members. These panels are the perfect size for the trailer as the 37” length just fits the raised center roof width without going over the edge radius. I was able to install 3 panels for a total of 240 Watts. Note that I chose the standard panels without the edge protection as I feel the existing edge will take the wind load and minor dirt and bug impacts. I did not want the additional thickness of the edge channel where I was going to bond.
2. 30A MPPT Solar Panel Regulator Charge Controller and LCD Display Remote Meter (MT-50) 12/24V. The website shows this controller as a Lensun product but it is actually an EPSOLAR unit. Many suppliers identify EPSOLAR components as their own. In fact, I found Renogy had better manuals on line for the monitor than what came with the component. I could have used a 20A controller but the 30A is only $10 more and will allow me to add external panels at a later date if I so choose. I ordered it with a remote monitor, which allows monitoring of the system without going under the dinette bench and is easier to use to program the controller with than the controls on the controller itself. It also makes it easier to enter the specific charge parameters for my batteries (factory 2 x 6 volt flooded) instead of the pre-set values. I did enter my own user values.
3. I also ordered the MC4 connectors from Lensun as it was easy and the cost was competitive. I did order breakers and a DIN mount, additional panel wire for the roof, and adhesive tape from other sources. I borrowed the MC4 crimping tool from Jim Bennett and my buddy 3D printed me some MC4 wrenches.
Panel Installation on Roof.
I installed one panel at the front, one in the middle, and one at the rear of the trailer (see photos).
Note that the highest structural loads on the panel do not come from wind on the leading edge, but from any lift from the airflow (Bernoulli's principle for you aviation/fluid dynamics guys). I considered using Eternabond or 3M VHB tape and feel that both are good options. Both have the strength and will seal the edges from water ingress. The Eternabond tape is likely safer if you are at all concerned about bonding preparations as I feel it is more forgiving if there are preparation issues. I decided to go with the VHB tape as I liked the look better (not that you can really see it from the ground) and have high confidence in its bonding capabilities from my experience using it in aviation design work. It is also used for bonding panels on cargo trailers, panel trucks and skyscrapers so I was not concerned about using it on these panels. I also believe it is easier to remove than Eternabond if you ever need to replace a panel and 3M provides instruction and sells the tools for removal. It does require careful surface preparation to prevent bond failure.
I chose 3M VHB Heavy Duty Mounting Tape 5952 Black, 3/4 in wide x .045” thick. This tape is good for high to medium energy surfaces (high being very glossy smooth). It also has good thickness to account for variations between the two surfaces. It is weatherproof. I chose ¾” width even though my calculations showed ½ was adequate, just for an additional margin of safety.
Panel Preparation:
• Clean the panel bond areas with IPA (Isopropyl Alcohol, not India Pale Ale).
• I ran tape around the entire perimeter which is overkill for strength but I wanted to seal out any moisture. I also put it over the redundant grommet holes at the corners, and sealed the grommets with calking to prevent water ingress.
• I also put three 6” strips equally spaced under the panel, longitudinally to the trailer. This was to prevent the panel from sagging inside the perimeter tape and prevent any chaffing (however unlikely) between the panel and the roof.
For the roof I did the following:
• washed the roof with soap and water and rinsed with clean water
• cleaned the area with IPA
• masked the perimeter of the panel profile with painters tape
• lightly scuffed the area next to the tape where the VHB will bond with maroon 3M Scotch-Brite to improve the bonding surface
• cleaned the area again with IPA
• peeled off all the surface film on the center strips and pealed a small length of the surface film on the perimeter tape and placed the panels in position. I did this rather than pealing it all off at once to give some forgiveness if I accidentally set the panel in the wrong position.
• pulled off the remaining film and pressed the panels in place
• using a hand roller pressed all tape contact areas down firmly
• removex the painters tape
3M data states: “After application, the bond strength will increase as the adhesive flows onto the surface. At room temperature, approximately 50% of the ultimate strength will be achieved after 20 minutes, 90% after 24 hours and 100% after 72 hours. Handling Strength is typically achieved immediately after application of pressure to the bonded components. In some cases, bond strength can be increased and ultimate bond strength can be achieved more quickly by exposure of the bond to elevated temperatures (e.g. 150°F (66°C) for 1 hour)”. 3M also has a graph that shows curing over several days at 10°C (50°F).
Being in Calgary in May I was concerned about bonding temperatures. The forecast for the day was for a high of 19°C (66°F) and lows of 3°C (37°F). I was a bit worried but in the end it was a very sunny day and the surface area of the black panels was measured to be around 125°F and the panels were at these temperatures for at least 4 hours.
I secured the cables with black tie wraps (zip ties) and the wrap mounts were also secured with VHB tape.
I did a 270 km (168 mi) trip this weekend with speeds up to 120 kph (75 mph) and we have had lots of rain since the installation and nothing has lifted or moved.
Controller and Monitor Installation:
I installed the controller on top of the black water tank under the driver’s side dinette seat where the pre wired cable ends installed at the factory terminated (see photo). I used circuit breakers on the positive wire entering the controller and exiting the controller to the battery, the same way Jim Bennett did. This was not only to provide circuit protection but also as shut off switches to isolate the controller, if required. I had to make a small mounting plate to fit the breakers in front of the controller and mounted them on a DIN strip.
I installed the monitor in the overhead bin bulkhead forward of the main door where it is easy to check by just poking your head in the door (see photos). To connect it there, I had to get a CAT4 cable longer than the one provided. You can use a cable up to 50 meters long. I had to drill a 2.5 inch hole to flush mount the monitor unit.
Circuit layout (see wiring diagram):
My wiring seems to be typical of most solar installations that I have seen with one exception. The controller has provisions to run the trailer load. I think this is common on many MPPT controllers but I have not seen it used (in my limited experience with other solar installations). I removed the main 12 volt jumper from the battery self-reset breaker to the 12 volt disconnect switch, and connected the 12 volt source wire from the controller to it. The system is now protected by the breakers I installed for the controller. Note that my trailer, which was completed in December 2019, has this switch under the bench and not on the front of it, and the switch has a large removable key.
The advantages of this are:
• The system uses power directly from the panels to power the load and uses the battery to top it up. This means you only draw down the battery when you are not providing enough from solar.
• This allows the monitor to also display the system load draw, along with the PV voltage/amperage output, and battery voltage and amperage in/out. It also displays if the battery is charging or being discharged.
• You can turn off the 12 volt load at the monitor without going to the 12 volt shut off switch under the dinette bench.
In conclusion, I am very happy with the installation. When camping last week we had one night that left surface ice in the dog’s water dish, so the furnace ran a fair bit (not a scientific measurement). The next day was a bit cloudy and the batteries were fully charged by mid-morning. I am very happy with the ease of monitoring the solar, battery, and trailer load. It will meet our current and foreseeable power requirements.
Here are other customers' questions to Mr. Mark about the heat issue of solar panels.
Hi Mark,
Your installations looks great. I am considering adding a panel or two to my 19. Some of the concerns I've read about with flexible panels is reliability and heat buildup. Some people suggest using a corrugated plastic board as a backer to help keep the heat away from the roof. Did you do that? Also are your panels removable in case they fail?
hi
I don't know how hot the panels get, but we measured mine at about 125 F in direct sun after installation. I could put my hand on them but it became uncomfortable quickly. I have put my hand on free standing panels on a hot day and it was not much different. Jim Bennetts have been on for over 3 years which included some months in the southern US and the Baha, Mexico and he has had no issues. Note that he installed with Eternabond tape, not VHB. To me the benefits of the low profile semi-flexible panels that I detailed in my original post are worth it.
I think that eventually the panels could/will lose efficiency or possibly fail. Everything does. A part of my choosing VHB tape, other than not wanting to drill holes, is that 3M gives instructions for removal of the tape. You use a garrote (thin wire like the high E string on a guitar) and cut through the tape core to remove the panel. 3M also sells a rotary tape remover to use in your drill (looks a bit like a rotary eraser) that takes the remaining adhesive off. I watched a video on line showing use of this tool to remove the VHB tape of of a car without damaging the paint.
I wanted my panels sealed so I did not get moisture under them. I did not want to put something under the panels to raise them, other than a few spaced out pieces of the VHB tape, as I felt it complicated the installation and made it harder to seal. The panels do have to curve to fit the roof, especially at the rear position. Corrugated plastic board would effect this. You maybe could do something like this with the Eternabond tape which is wide enough to go over the panels and a thien secondary layer, but to use the VHB you would be stacking bonded layers to attach the panels.
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