Designing - The Panels

Now that I knew the size and power output of the cells I could actually start thinking about the panels and what arrangement I wanted the cells in. I decided against planning to use all 10 cells, one might get messed up during soldering and then I'd have to redesign the whole thing all over again. 8 cells seemed like a good balance between using as many cells as I could while still having the safety of 2 extra cells.

I considered putting all 8 cells into a single panel and having it strapped to the kayak, but really? That's kinda boring and I didn't really feel like going to all this effort just to have something as simple as that. So the idea got more complex, rarely a good thing in engineering projects but in this case, it was exactly what I wanted.

At this point, I was playing around with different layouts on a website called TinkerCAD, this is a really nice piece of software to use for some basic 3D modeling. It won't take you very far once things start to get complex, but for some basic stuff, it works really well.

Here's the panel in TinkerCAD. The solar cells are blue and the transparent bit on the right is the plexiglass cover. I went with a very simple panel design, the 4 cells in a row and a basic wooden casing to hold the whole thing.

Below you can see a colored cut through of the panel. There is a small lip for the plexiglass to sit on (pink) and an edge running around the entire panel to hold the plexiglass in place (orange).

Almost everything was designed to be cut out from 3mm (1/8') plywood.

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Designing - The Cells

A distinction I should make before going any further is the difference between solar cells and solar panels. When I am talking about the solar cells I am talking about the individual square parts inside of the panel. The panel being the housing for the cells, some sort of stiff material for the back and a sheet of glass over the front. The cells produce power and the panel houses and protects the fragile cells. The first step of designing the solar panels was to get the actual solar cells I'd be using since literally, everything was dependent on their size. I was able to find some panels for fairly cheap on eBay, so I officially began the project with the purchase of 10 A Grade 4.8W 19.6% 156mm Mono Silicon Cells. Here's what that means: A Grade - Panels are completely intact. B, C, or D Grade will have increasingly large chips missing from the cells. Read more here. 4.8W - This is the power output. 19.6% - This is the claimed efficiency of the cells. ...

Update - Drive System

Right, so my suspicions about the bond between the drive arm and drive arm were correct. When I tried to extend the panels using a pair of pliers the epoxy joints cracked and the axle broke loose. The panels did not extend at all. I've drilled a hole through the drive arm and axle, I epoxied a nail into the hole and it seems to be holding. I can now extend the panel with pliers. It takes quite a bit of force to do it. I kinda doubt a servo will be able to handle it.

Building - Arms Pt. 1

Building the arms was by far the most time-consuming task. If only I had a cnc.... The rim of wood around the bearing was needed but I didn't like the really thick arm, I drew this up in Fusion, printed out the drawing, and stuck it down with a glue stick. The slot in the middle was an idea to make the arms lighter and look cooler. I tried it with one arm and then ditched the idea, it really didn't work and was a lot of work. All cut-out, at this point I didn't have access to a scroll saw so this was all done with a regular handsaw and files. It's pretty rough but I cleaned it up as best I could. Already looking much better. The next step was mass production, I needed 20 arms total. For this, I bought a used Craftsman Scroll saw. It was very, very useful. All cut and drilled out. Removing the paper was annoying, I used the top edge of a file to scrape it off. Since I put it on with a glue stick it wasn't very difficult to scrap...

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