Introduction: DIY 12 Volt Solar Panel
A DIY 12 volt solar panel that will provide years of electricity with little to no maintenance.
This is a 12 volt (18 volt +/-) diy solar panel that you too can make at home. Your parts list is below and nearly all supplies can be purchased at Lowes with the exception of solar cells and tabbing wire.
1. smart siding, 96in x 48in. Cost roughly $29.
2. 36 3x6 solar cells (i used 40).
3. some kind of exterior clear spray on or brush on wood protectant.
4. 38in x 28in panel of 1/8in or slightly thicker clear polycarbonate or plexi-glass (preferably with a UV protectant built in)
5. I in x 1/2in wood strips total 132 inches long to be cut.
6. waterproof wood glue.
7. All your normal solar panel soldering supplies, (ie: tabbing wire, solder, flux, solder iron)
8. a tube of clear exterior caulking.
9. Your choice of exterior paint or not if you like the original color of the woods.
10. 4 small twist tighten clamps.
11. small 3/4 inch galvanized screws that do not tapper at the head but are flat at the head.
12. 132 inches of some cheap rubber weather stripping that is 1 inch wide just like the trim. Should be sticky on one side.
13. drill with a quarter inch diameter drill bit and a phillips head screw bit
1. Cut one or two 38x28 inch section from the smart siding. This is the same size as your plexi-glass. You should be able to get two from this board with some nice left over pieces maybe for a smaller solar panel.
2. Also cut your 1x1/2in trim pieces for one or two panels. for one panel you'll need two pieces cut to 38 inches and two pieces cut to 26 inches. Glue the trim pieces to the smart siding pieces and clamp them down over night. Be liberal with the glue and smear it around really good as opposed to just using glue dots. Remember that this is supposed to be water proof wood glue and will play a life long role in keeping water out of your finished panel. If you use a couple 2 x 4 pieces of wood when clamping down the trim pieces, it will distribute the pressure of the clamps much better and you'll need less of them to clamp the trim pieces really good.
3. Go get a beer and call it a night! We'll continue tomorrow with step 3.
OK. Glue is dry and the panel is coming along nicely...easy isn't it!
1. Figure out which end is going to be the top end of your panel then drill some holes along both sides of your panel that are angled downward towards the bottom end of the panel. So, just to be clear, when you're drilling, the drill bit is drilling towards the top end of the panel. These are your venting holes that allow air flow but no water to get in. If you hang the panel upside down then this step is useless :) The holes need to be about a quarter inch in diameter to allow for adequate air flow.
2. Now, if we decided to paint the panel along with the trim pieces, we will do so. Paint it good the first time so you don't have to do it again. Make sure that you are using a exterior paint.
3. Let this dry for a couple hours or you can speed the process up with a fan like me...I like to get going with my projects.
4. Now that the paint is dry, you will need to liberally apply the clear exterior wood protectant. I used a polyurethane brush on. You want to apply to the entire panel, trim, front, back, etc. Everything gets a good coat. I applied two sopping wet coats and let it dry with a fan in between each coat. I'd plan on picking up step four tomorrow.
Now's a good time to get all your solar cells tabbed and ready to be lifted and put in place on the panel tomorrow. When tabbing your cells together leave about 1/2 an inch between each cell (like in the picture).
You now have a nice shiny watertight frame for your solar cells to be placed in.
1. You should have 4 columns of 9 cells ready to go. 36 cells equals roughly 18 volts for your panel and this is where it needs to be for a 12 volt panel.
2. Arrange your solar cell columns in the panel making sure to alternate your positive and negative ends to correctly connect them. Solder the ends of each column correctly so that your positive and your negative both end on the same end of the solar panel. Test the panel!!! drill a couple holes strait through the panel for the tabbing wire from each positive and negative to go through. You may have to solder extra tabbing wire, or even may decide to use regular wire instead of tabbing wire, to extend it through each hole.
3. Use the clear caulk to dab a small round blob in between each solar cell right on the tabbing wire but big enough so that it also touches the wood (like in the picture). This will dry and hold the cells securely in place.
4. Caulk the length of positive and negative wires up to and in the drilled holes really good....goop it on. This will hold the wires securely in place and prevent damage to the cells if the wires are accidently pulled from the back of the panel.
5. I don't use a junction box on the backs of my panels but you can add this if you'd like. Looks really nice if you do.
1. Cut and stick your rubber weather stripping directly over the trim all around. Use the clear caulk to fill in where the rubber stripping meats another piece of rubber stripping. Also, if you have any gaps where the wood trim is glued, use the caulking to fill in the little spaces. Take your plexi-glass and place it exactly on top of the panel and clamp it down on each corner. Use a piece of cloth between the clamp and the plexi-glass so you don't scratch it. Now, it will not move at all while you pre-drill some holes every 2 or 3 inches through the plexi-glass into rubber stripping and into the wood trim. You can go all the way through but if you do, flip it over and add more polyurethane to the back of the panel where the holes are or some caulk. You can do this last, no big deal.
2. Now put a screw in each hole and gently screw it in. you don't need to screw it in so hard that it completely depresses the rubber strip. You only need to depress the rubber strip slightly for it to do it's job.
3. You're done! It will fog up for a while on the first sunny day after rain but it shouldn't last too long. If you ever drop your panel or somehow break one or more solar cells in the panel, you can unscrew the plexi-glass, use a razor to cut out the bad cells where the beads of caulk are and solder in new cells. I know it works because I've had to make two repairs on mine. Rain, snow, hail will not ruin this panel. I plan on reapplying some polyurethane to the sides and backs of mine soon. If some of the glue comes undone, just reapply and clamp again in the spot that needs it. This panel does not have a diode because I connect it to a charge controller so, don't hook it strait to a battery and leave it. I always recommend using a charge controller because otherwise #1, it will overcharge the battery eventually and #2. it will suck the life out of your battery when the suns not shining because it doesn't have the diode. If you want, add a diode.