Now we’ve bought a second solar panel, I’ve been working on a tilting frame for it, and I thought I’d share how I did it in case anyone else wants to get one.
I’d settled on a design like this
which you can buy from a few places on line for £35 or so. The idea was to have it so that I could have the panel secured flat for travelling or tiled to 40 degrees from horizontal to get the best radiation. Apparently 40 degrees is what you need for optimum average performance in the southern half of the UK.
I costed up the bits I would need to make my own, using aluminium for aluminiumwarehouse.co.uk which was the cheapest place I could find and I could have saved a bit, but factoring in the postage and the cost of the screws and knobs it didn’t save a whole lot, so I decided to buy the ones shown above and tweak them to my requirements. Here’s where it gets interesting.
The kit you get is pretty sturdy, but in my view it isn’t ideal for use if you want to be able to have the panels quickly adjustable from locked flat to tilted, especially if you want to be able to choose whether to tilt port or starboard at any given location. For a start, the holes on the "hypotenuse” don’t match up with those on the base when you lie it flat, so you can’t lock the panel down with the screw knobs. Secondly, because the hypotenuse is longer than the base, it’ll only tilt one way unless you unscrew everything and slide the panel to the other end. If you think about it, the bars have to meet at a point at the fulcrum end , otherwise the overhang would hit the boat roof before you got it up. I suppose if the bottom piece was longer than the top, it wouldn’t be a problem. But then you’d have sticky out bits of frame to catch on your boat’s centre ropes. Sorry if you’re having trouble envisaging all this, I’ve had rather longer to mull it over.
Luckily, I’m building these for two panels of different widths and so by buying two kits I was able to mix and match the components to make frames to suit my requirements. My new panel happens to be nearly the same width as the “base” piece shown above, so what I’ve done is to take those pieces from both kits and make a frame with the base and the hypotenuse the same length. The holes match up to lock it down and I can get very close to 40 degrees tilt, like so:
The prop piece will have to be removed when the panel lies flat. Here you see it all upside down of course so you see the feet sticking up. I have it face down on the table to prevent it from generating electricity. As you can see, a range of angles is available, so in winter I can tilt it more if required. Whilst I’m on that subject, on our old panel I have monitored the difference in amps between lying flat and propped up and the difference is significant.
At the other end of the panel you can see the frame folded and locked flat. here’s a better look at it flat.
The fixed side of frame is bolted to the end frame of the panel by four screws and locking nuts. The feet I had to buy separately. They have a small amount of wiggle so they’ll lie flat against the curvature of the boat roof. Once I’m happy with the setup on the boat I’m going to glue them down with Sikaflex.
There was one further problem. The tilting edge wouldn’t go up to the required angle until I chamfered off its corner like this:
Otherwise it interfered with the other half of the frame. Incidentally, you can see here that the aluminium itself is of a good thickness.
So that’s one done, and the bits I have left are long enough to do my old wider panel the same way. You have to get lucky sometimes.