Solar Power Set-Up In The Desert

 If you think you have read that very same headline before on this blog, you are absolutely right. I have consciously chosen the same headline.

Link to the page from 2012:

https://american-traveler.blogspot.com/2012/12/solar-power-setup-in-desert.html

This time though, the solar project has a different dimension.

Our rig has a residential fridge, meaning it needs 120V all the time. So in order "to feed that thing", and keep us with power for other gadgets, we need a certain amount of battery capacity and power generating capacity.

So far, we have used our small 2000W inverter generator. Combined with a smart-charger, I had to set the charger on either 20amps or 40 amps to keep our batteries charged up and the on-board inverter running.

But we don't like generators running. So obviously, quiet solar power would be the answer.

Checking our the available space on our roof, I came up with a plan to order 12 100W panels, 6 on either side of the rig. Bigger panels were available, but I couldn't find space for them on the roof. These panels, brand new, were $717 plus tax only. The first 100W panel we ever bought back in 2002 was $500!!! So prices have come down a lot.

The ordered panels have arrived and we picked them up at the host station.

I have spent hours upon hours of planning how to mount these panels on the roof. Watching youTube videos has helped. The problem was that we don't have a plan of the steel-truss layout of this rig. That makes using screws into the roof difficult. And the roof has no plywood of substantial thickness, all it shows is 1/8" of something called luaun, which is a very, very thin sort of plywood.

The skin of the roof is alluminum and most of the rest of the roof is foam insulation. So no good for putting screws into it.

In my search for a solution I watched a video where an RV-owner mounted solar panels without drilling any holes. What he used was a double-sided tape. 

It was strong enough to hold down the entire installation. Yet he reenforced it with 'Sikaflex', a combined adhesive and caulking. Though I was very sceptical I found this idea very interesting. And maybe, just maybe on,e could get 2 or 3 screws into the steel trusses of the rig. I used a deep-scan stud-finder to locate some trusses and marked off the center line on the roof.

So what did this RV-guy put on the tape? He used strut-channel, which is used by electricians. Strut channel is commonly available at both Home Depot and Lowes, and probably at some other stores as well.

I went to Home Depot in El Centro. I bought 8 10ft strut channels, which was almost all the store had in stock. The actual mounting of the solar panels is gonna happen by mounting them on crossbar angle-irons. Strut channels come with strut-nuts and bolts. Home Depot did not have enough of them, but I will get the missing amount from Lowes soon.

Today was the day that I climbed up on the roof.

First, I had to make lines for where the strut channels were gonna be. The distance between the channels would be 2ft.

After I had thoroughly cleaned the surface of the roof, first with water, then with alcohol, it was time to get the double-sided tape. The roll was wrapped in plastic and had a paper attached to either side. I removed all of that, which turned out to be a big mistake. The tape I use is called ETERNA BOND. The name hints on eternity and I was about to learn about what that meant for this project.

So I unrolled the required length of 10ft for the strut channel. Both sides of the tape have a plastic strip on the sticky surfaces. Cautiously, I removed the plastic on on one side for 5-6inch only, then set the end of the tape into position. Now I peeled off more of the plastic and gradually put the tape down along the lines I had put on the roof. Once that was done I pressed down the take with my hands all along the length of it.

While I had been working with lining up the tape, the roll fell over on its side. When I wanted to grab it, I couldn't pull it of the roof. I finally had to use all my strength to pull it off. This, of course, was the result of removing the protective paper on the side of the roll. So I quickly put the paper back on. The stickyness of this product is simply astounding.

Then I took one of the strut channels and put one end down on the tape, first then I lowered the metal channel  onto the tape. Once it was sitting there I stepped on top of the channel pressing it fully down on the tape using my weight of 76kg.

Naturally, I now was curious how well this would hold up. So for a test I grabbed the channel at one end with both hands trying to pull the channel off the tape. My sceptic mind was taught a lesson. There was no way that I, or anybody else, would be able to pull the channel off the roof again. once it was glued to the tape, it would stay there for good.

If one takes into account that I am also gonna use SIKAFLEX along the channel to further improve the hold on the roof, it becomes clear that screws into the roof would not be needed. No screws also means no risk of potential leaks in the future.

Let me also say, that it is nearly impossible to cut the tape with a knife. Once the blade is touching the sticky part, it pulls the material behind like chewing gum.

I still need more parts for completing the project, but once we have further progress, I will put out more postings.

While all of this is under development, I have hooked up 3 panels, positioned on our trailer. They are connected in parallel and during day hours, they feed great power into the batteries. The use of our generator is now reduced to a few hours in the evening.

By-the-way, though solar power is great, it needs to get paired with enough battery capacity. 

We have 4 new Trojan deep-cycle batteries with a combined capacity of 900 amp-hours. 12 100W solar panels will be able to feed 60amp-hours over approx 6-7hours a day. Since our batteries will never be 100% discharged, the system with the coach inverter will be able to keep us with power 24hrs/day.

Want to follow this project? Check back in a few days!