I’ve installed my massive solar array. I have 10 flexible panels at 100 watts each for a total of 1000 watts. I purchased them here. They changed their website and you must request a catalog now. Why do I have a huge solar array? Because I’m doing an all electric van conversion and I will be able to run an air conditioner for a few hours per day.
Since I knew they would overhang slightly, I was originally going to put them on a roof rack. That option proved to be too expensive. So instead I decided to mount them with VHB tape directly on the roof. I was skeptical of using tape to mount solar panels at first. Then I watched this video and did a little more research.
I purchased 5 yards of a model specifically for painted metal and plastic adhesion from amazon. I can say first hand that this tape is as strong as they say when it is used on metal and plastic. 3M makes a few other versions for different surfaces. Amazon Link: 3M 4941 VHB Double-Sided Acrylic Foam Tape, 45 mil, 0.5″ x 5 Yards (Dark Grey)
I had to lay out the panels on the floor and decide where the wires would go, and where the tape would go. I overlapped the panels at the edges to save room.
Substrate preparation is the key to good adhesion. I followed the steps in the video below, but I added some of my own. After the alcohol, I used a heat gun on the van with the low setting. Just enough to evaporate any water content left over from the alcohol. Adding heat also helps the bond form. Then I put a weight on the tape for a few minutes.
Over the VHB tape, I applied painters tape to prevent the wax paper from coming off while I worked on the roof.
For each panel, I had a wire orientation plan.
After placing the wires where I wanted them. I prepared the back of the panels for the VHB tape. The only difference was that I used sand paper to score the back instead of the scrubber.
I pressed down firmly in each tape location for about two minutes. Then I put a shoebox with water bottles on top to maintain constant downward force for about 5-10 minutes. The towel was to avoid scratching the panels. I had to learn that the hard way with the first panel. By the 10th panel, I felt like a pro.
I’m not going to discuss the circuit diagrams here. I’ll have a whole blog post about wiring the entire van. I just want to show what I physically did with the four leads going into the van. I basically cut off the MC4 connector and butt spliced with a water proof shrink wrap splicer. I picked them up at home depot along with the wire.
Drilled a hole behind the fan for wire entry. Then inserted a grommet that I could fit four wires through.
Poked a hole in the reflectix.
This is called a cable feed gland. It’s designed for a single larger wire, but I used it for four #12 wires. It was still able to seal around the wires tight enough to prevent leaks. To mount it, I used some leftover VHB tape. Amazon link: Instapark® IN-SW Surface-mountable Single Cable Feed-thru Gland with Adjustable Grommet & Blanking Plug, Color White
I used dicor to seal it. I had some leftover from the fan installation. When using it to create a seal at a 90 degree angle, I had to place it a little higher than where I wanted it to be because it well lower over time until it cures. It made a great seal and I haven’t had any leaks. Amazon Link: Dicor EPDM Rubber Roof Lap Sealant, 10.3 oz, White 501LSW-1
When it is tightened, it squeezes the wires with rubber to create a water tight seal.
So the solar panels hang over a little bit. Does it take away from the stealth? I can’t decide. I wish the sprinter roof didn’t taper in so much.
There were some sacrifices I made to fit 1000 watts on my roof:
- I can’t access the wires or their connections underneath the panels.
- If I need to replace a panel, it will be hard to get the VHB tape off.
With that being said, I’m happy about the following;
- It is somewhat stealth
- I have hella power
- It doesn’t add much weight
I’m still on schedule to leave at the end of the month. I have finished the kitchen, but I haven’t written that post yet. I just sat down for a minute between working in the garage to type this one out. My plan has changed slightly. When I leave, I think I’ll just take a short trip to NJ and back for about 2-3 days. This will allow me to work out any kinks in the van when I get back to the garage. I have the garage for another 30 days, but I definitely won’t stay in PA that long. I just need about a week to tie up some logistical loose ends and say goodbye to some friends before I leave permanently. Today I’m finishing the ceiling and the next two days I will build the closet structure.
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Here’s a shot of the van from far away with the solar panels on top. I think it still looks pretty stealthy.
I’ve been getting some feedback from the sprinter-source.com forum about VHB tape and sprinters. Apparently, the tape works great, but the paint bond on the sprinter fails sometimes. I will keep an eye on the solar panels. If I see the paint start to come up, I will use rivets to keep the panels in place. If it fails, It won’t be at all 40 pieces of tape at once. Rather, I think it’ll be gradual with couple spots failing first. So I’m not too worried about the whole solar array flying off while driving.
UPDATE 12/19/2016: I’ve replaced these panels. See the post about the new solar panels.
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