Solar Panels continued -
Warning: I wrote in the last posting about drilling through the penthouse top. Don't know if this is a common problem with epoxied fiberglass but after drilling one of the holes I reached up underneath the top to pull off a stray fiber and it sliced into the tip of my finger like a razor blade. Not that bad of a wound, compared to some others on this project, but it did surprise me.
Next up was to figure out the electrical wiring. With the two panels the first question was to connect them in series or in parallel. In series the panel output voltage is doubled but in parallel the amps is doubled. According to the solar controller manual doubling the voltage would be outside it's recommended range while doubling the amps was not, so in parallel they shall be.
Now think how to route the wires.
The panels come with these MC4 connectors. If I cut these off it would void the warranty so I bought a pair of extra cables instead. Those I can cut up.
Found this out the hard way. To disconnect the connectors on the panel slide the shield out of the way then take two small screwdrivers and squeeze them on each side.
The connectors will pop apart.
There will be a bunch of cable slack underneath the panel that needs to be organized so it doesn't hang down. I'll be using nylon anchors and zip ties to keep the wires in place.
Didn't want to trust the foam tape that came with the anchors so scraped it off and replaced it with VHB tape.
Each of the two cables I bought had a male and female end. I cut and spliced them so that one wire had two male ends and a uncapped wire while the other had two female ends and one uncapped wire. These would be my two parallel cables. Used wire nuts where I joined the wires.
Then covered the wire nut with heat shrink.
This will be the wire route. Notice where the two wires cross between the panels. I'll come back to that.
So how to get the wires through the penthouse top? If I was to drill straight down through so that the hole is outside the canvas then the wires would extend upwards outside the edge of the solar panels. Don't much care for how that would look beside it would be more apt to leak. Have to think of something else. Time to bring out my most important tool. My thinking stool.
So I'm sitting there thinking, do a lot of that, and looking around the garage when I see this on a shelf. A nylon rod. Gives me an idea.
Cut off a section of the rod. Drill two holes in the rod. Each a little larger than the diameter of the electrical wire on the parallel cables.
Bisect the rod at a 45 degree angle.
Find a piece of scrap wood the same thickness as the roof. Knew that roof measurement I took earlier would come in handy. Hold the half rod tight against the plywood and use it as a drill guide.
Slide one of uncapped end wires through the half rod and plywood to see where it exits on the underside. The small tip of the half rod lies almost directly above where the wire exits.
Using that as a guide decide where is the best place to put the half rod on the roof. For this picture I have the van turned around from it's usual orientation so this is actually the drivers side.
Cover the bottom of the half rod with VHB tape and stick it to the penthouse roof. Use it as a guide to drill through the penthouse top. Really took my time with this since I was drilling at such a shallow angle
After using both holes in the half rod as drilling guides you can see that the two holes line right up with the bolt hole underneath the roof. Really glad I got that right. Epoxy treated these holes just like I did with the bolt holes.
continued.
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