Living in South Africa we have 320+ sunny days a year but very little uptake of solar technology. This was mostly due to the fact that we had cheap (but not reliable) electricity from our sole national power supplier. This situation changed drastically over the last few years with electricity prices tripling to try and raise the funding for a massive expansion of the now grossly over-utilised national grid. Energy prices have sky rocketed and reliability has plummeted. The upside of this was that the prices of solar panels and LED technologies dropped drastically and the availability became more first world as more entrepreneurs ventured into the import and supply of alternative energies.
The three small (12-25 Volt, 25Watt) panels cost me R250 (approx $30) each from a pawn shop about a year ago and they became a project waiting for a place to happen. I mounted one of the panels on the side of my garage using an old tool rack and hooked it up to a 12 volt CFL (Compact Fluorescent Lighting) that I bought for R36 ($5). I hacked a day/night sensor so that the 12 volt CFL switched on automatically at dusk and burnt the whole night long before switching itself off at dawn. The 12 volt batteries were more than capable of sustaining the CFL for 2 weeks or more with no charge at all so with full solar charges, the bulb switched itself on and off for the next year with 100% reliability and the single solar panel kept the batteries topped up on a daily basis. And that was as far as the project got for the next year.
I am currently in-between contracts and have the time on my hands to do some work around the house. I hate window blinds and so have been systematically removing them from all the windows (the previous owner of our house obviously loved them!) It was during one of these removal sessions that I realised that the aluminium channel would be the perfect fit for the solar panels.
This instructable is then the result of that brain wave and the resultant frame and mounting of the solar panels. Unfortunately I never intended to make an instructable out of this and it is only because of the success of the finished product that I decided to share the project with you. If the demand requires, I will dismantle the finished product and do a proper step by step instructable.
The three panels now charge a dual bank of 12volt batteries (reclaimed from a defunct UPS) via a dual solar regulator that cost R250 ($30). The intention is to drive all of the perimeter lighting of the property and the electric garage motors so that when we have one of our extremely regular 4 hour long blackouts, the property remains relatively secure and accessible.
Step 1: Old Test Install
Just for interest sake and context, these brackets taken from a workshop tool hanging kit were turned upside down and modified to fit one of the panels. The solar panel slotted between these brackets and was still secure over a year later. Not bad for a chewing gum and string temporary trial.
Step 2: Strip Blind Rails
I will keep this step generic because it will greatly depend on the manufacturer of the blinds and hardware that you have to hand what steps are required. For the blinds I was using, it was a simple screw at each end and for the rails over 2 meters long, one or more in the middle. The offending innards were removed and I was left with a clean virgin rail that fitted my solar panels perfectly.
Step 3: Make the Frame
Again this has to be generic because your solar panels will have different dimensions. Another consideration for me was the extremes of weather that we experience here in the highveld of South Africa. The hail can get to golf ball or larger in size and the summer storms are violent with high gusting winds. For this reason I wanted the install of the panels to be elastic to absorb impact shock from ice missiles and I wanted to reduce the effect of the wind by leaving gaps in between each individual panel. Since we are currently going in to winter here in the Southern hemisphere it will be 8-9 months before I know if my design reduced the threat or if I have just led three solar panels to the roof altar to be slaughtered.
I still have to find some way of providing a cushion at the bottom of the panel frame were it meets the roof, all suggestions greatly appreciated.
I joined the frame using simple steel brackets and a rivet at each joint. As you can see, I had every intention of putting in three rivets per corner but I found that one rivet was more than sufficient to hold the frame together. The solar panels are provided with their own aluminium siding and rubber seals. These were left in place to maintain the integrity of the manufacturers waterproofing.
The panels are not fixed to the inside of the rails, the rails are wrapped around the panels and then riveted closed. This encapsulates the panels allowing them room for expansion, movement and shock absorption. A 2cmX2cmX2cm wooden block was then cable tied in to place to take up the slack room in between each panel.
I was pleasantly surprised at how snug the whole design worked out and the panels are kept firmly and safely in place whilst being allowed to move and flex with the weather.
Step 4: The Genius - Modifying the Blind Brackets
Simply take each bracket, bend in the middle to the required angle and bolt to the roof!
I was amazed at how firmly these brackets grip the blind rail. Once the clip is in place no amount of twisting and wrenching will pull it loose until the release tab is pressed.
The other advantage is that I was then able to mount the panels by myself. I slid the top of the panel rail in to the top of the clip and then dropped the "feet" of the panel on to the roof and then with a little persuasion, the clips took hold with a firm and gratifying click.
I tugged and pulled at the panel to try and get the grips to let go but they were steadfast and sure! All that was left to do was the wiring.
Step 5: Wiring and Other Bits
I won't waffle on any more, here are some more pictures to try and cast light on the unexplained, unclear or misty concepts. Please remember that this was an "on-the-fly" hack, I was making it up as I went along so, yes, my riveting sucks and my angles are not pristine, they were never meant to be!
I hope this instructable oils the gears of the fertile minds that visit this web-site so that something better may become of my simple hack.
Thanks for the interest and please feel free to post any comments or suggestions. Please note that the answer to any "have you tried xyz with a blodge of thimmagy" or "what if you mix the blue spectral fangdadgit with the opague whatsimmit" is NO, I haven't because as I have already explained, this was made up as I went along. If you want to know the results of such machinations and finagling's then you try it out yourself and post the results!