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Picture of Build a 60 Watt Solar Panel
Several years ago I bought some remote property in Arizona. I am an astronomer and wanted a place to practice my hobby far away from the terrible light pollution found near cities of any real size. I found a great piece of property. The problem is, it's so remote that there is no electric service available. That's not really a problem. No electricity equals no light pollution. However, it would be nice to have at least a little electricity, since so much of life in the 21st century is dependent on it.

I built a wind turbine to provide some power on the remote property (will be another instructable in the future). It works great, when the wind blows. However, I wanted more power, and more dependable power. The wind seems to blow all the time on my property, except when I really need it too. I do get well over 300 sunny days a year on the property though, so solar power seems like the obvious choice to supplement the wind turbine. Solar panels are very expensive though. So I decided to try my hand at building my own. I used common tools and inexpensive and easy to acquire materials to build a solar panel that rivals commercial panels in power production, but completely blows them away in price. Read on for step by step instructions on how I did it.

You can learn more about this project and my other alternative energy projects, including my home-built 15 Watt solar panel, my home-made wind turbine, and my biomass gasifier on my web site.


 
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Step 1: Buy some solar cells

Picture of Buy some solar cells
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I bought a couple of bricks of 3 X 6 mono-crystalline solar cells. It takes a total of 36 of these type solar cells wired in series to make a panel. Each cell produces about 1/2 Volt. 36 in series would give about 18 volts which would be good for charging 12 volt batteries. (Yes, you really need that high a Voltage to effectively charge 12 Volt batteries) This type of solar cell is as thin as paper and as brittle and fragile as glass. They are very easily damaged. The Ebay seller of these solar cells dips stacks of 18 in wax to stabilize them and make it easier to ship them without damaging them. The wax is quite a pain to remove though. If you can, find cells for sale that aren't dipped in wax. Keep in mind though that they may suffer some more damage in shipping. Notice that these cells have metal tabs on them. You want cells with tabs on them. You are already going to have to do a lot of soldering to build a panel from tabbed solar cells. If you buy cells without tabs, it will at least double the amount of soldering you have to do. So pay extra for tabbed cells.

I also bought a couple of lots of cells that weren't dipped in wax from another Ebay seller. These cells came packed in a plastic box. They rattled around in the box and got a little chipped up on the edges and corners. Minor chips don't really matter too much. They won't reduce the cell's output enough to worry about. These are all blemished and factory seconds anyway. The main reason solar cells get rejected is for chips. So what's another chip or two? All together I bought enough cells to make 2 panels. I knew I'd probably break or otherwise ruin at least a few during construction, so I bought extras.

Step 2: Build the box

Picture of Build the box
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So what is a solar panel anyway? It is basically a box that holds an array of solar cells. So I started out by building myself a shallow box. I made the box shallow so the sides wouldn't shade the solar cells when the sun comes at an angle from the sides. It is made of 3/8 inch thick plywood with 3/4 X 3/4 pieces of wood around the edges. The pieces are glued and screwed in place. This panel will hold 36 3 X 6 inch solar cells. I decided to make 2 sub-panels of 18 cells each just so make it easier to assemble. I knew I would be working at my kitchen table when I would be soldering the cells together, and would have limited work space. So there is a center divider across the middle of the box. Each sub-panel will fit into one well in the main panel.

The second photo is my sort of back of the envelope sketch showing the overall dimensions of the solar panel. All dimensions are in inches (sorry you fans of the metric system). The side pieces are 3/4 by 3/4 and go all the way around the edges of the plywood substrate. also a piece goes across the center to divide the panel into two sub-panels. This is just the way I chose to do it. There is nothing critical about these dimensions, or even the overall design.

Step 3: Finishing the box

Picture of Finishing the box
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Here is a close-up showing one half of the main panel. This well will hold one 18 cell sub-panel. Notice the little holes drilled in the edges of the well. This will be the bottom of the panel (it is upside down in the photo, sorry). These are vent holes to keep the air pressure inside the panel equalized with the outside, and to let moisture escape. These holes must be on the bottom of the panel or rain and dew will run inside. There must also be vent holes in the center divider between the two sub panels.

UPDATE: After using the panel for a while, I now recommend that the vent holes be increased to at least 1/4 inch in diameter. Also, to keep dust and critters out of the panel, stuff a little fiberglass insulation in the holes in the bottom rail of the panel. The insulation is not needed in the holes in the center divider.

Next I cut two pieces of masonite peg-board to fit inside the wells. These pieces of peg-board will be the substrates that each sub-panel will be built on. They were cut to be a loose fit in the wells. You don't have to use peg-board for this. I just happened to have some on hand. Just about any thin, rigid and non-conducting material should work.

To protect the solar cells from the weather, the panel will have a plexiglass front. In the third picture, two pieces of scrap plexiglass have been cut to fit the front of the panel. I didn't have one piece big enough to do the whole thing. Glass could also be used for this, but glass is fragile. Hail stones and flying debris that would shatter glass will just bounce off the plexi. Now you can start to see what the finished panel will look like.

Step 4: Paint the box

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Next I gave all the wooden parts of the panel several coats of paint to protect them from moisture and the weather. The box was painted inside and out. The type of paint and color was scientifically chosen by shaking all the paint cans I had laying around in my garage and choosing the one that felt like it had enough left in it to do the whole job.

The peg-board pieces were also painted. They got several coats on both sides. Be sure to paint them on both sides or they will warp when exposed to moisture. Warping could damage the solar cells that will be glued to them.

Step 5: Prepare the solar cells

Picture of Prepare the solar cells
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Now that I had the structure of the panel finished, it was time to get the solar cells ready

As I said above, getting the wax off the cells is a real pain. After some trial and error, I came up with a way that works fairly well. Still, I would recommend buying from someone who doesn't dip their cells in wax.

This photo shows the complete setup I used. My girlfriend asked what I was cooking. Imagine her surprise when I said solar cells. The initial hot water bath for melting the wax is in the right-rear. On the left-front is a bath of hot soapy water. On the right-front is a bath of hot clean water. All the pots are at just below boiling temperature. The sequence I used was to melt the bricks apart in the hot water bath on the right-rear. I'd tease the cells apart and transfer them one at a time to the soapy water bath on the left-front to remove any wax on the cell. Then the cell would be given a rinse in the hot clean water on the right-front. The cells would then be set out to dry on a towel. You should change the water frequently in the soapy and rinse water baths. Don't pour the water down the sink though, because the wax will solidify in your drains and clog them up. Dump the water outside. This process removed almost all the wax from the cells. There is still a very light film on some of the cells, but it doesn't seem to interfere with soldering or the working of the cells.

Don't let the water boil in any of the pans or the bubbles will jostle the cells against each other violently. Also, boiling water may be hot enough to loosen the electrical connections on the cells. I also recommend putting the brick of cells in the water cold, and then slowly heating it up to just below boiling temperature to avoid harsh thermal shocks to the cells. Plastic tongs and spatulas come in handy for teasing the cells apart once the wax melts. Try not to pull too hard on the metal tabs or they may rip off. I found that out the hard way while trying to separate the cells. Good thing I bought extras. More details on this step can be found on my web site at http://www.mdpub.com/SolarPanel/

Step 6: Solder the solar cells together

Picture of Solder the solar cells together
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I started out by drawing a grid pattern on each of the two pieces of pegboard, lightly in pencil, so I would know where each of the 18 cells on them would be located. Then I laid out the cells on that grid pattern upside-down so I could solder them together. All 18 cells on each half panel need to be soldered together in series, then both half panels need to be connected in series to get the desired voltage.

Soldering the cells together was tricky at first, but I got the hang of it fairly quickly. Start out with just two cells upside-down. Lay the solder tabs from the front of one cell across the solder points on the back of the other cell. I made sure the spacing between the cells matched the grid pattern. I continued this until I had a line of 6 cells soldered together. I then soldered tabs from scrapped solar cells to the solder points on the last cell in the string. Then I made two more lines of 6 cells.

I used a low-Wattage soldering iron and fine rosin-core solder. I also used a rosin pen on the solder points on the back of the cells before soldering. Use a real light touch with the soldering iron. The cells are thin and delicate. If you push too hard, you will break the cells. I got careless a couple of times and scrapped a couple of cells. More details on this step can be found on my web [site at http://www.mdpub.com/SolarPanel/]

Step 7: Glue down the solar cells

Picture of Glue down the solar cells
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Gluing the cells in place proved to be a little tricky. I placed a small blob of clear silicone caulk in the center of each cell in a six cell string. Then I flipped the string over and set in place on the pencil line grid I had laid out earlier. I pressed lightly in the center of each cell to get it to stick to the pegboard panel. Flipping the floppy string of cells is tricky. Another set of hands may be useful in during this step.

Don't use too much glue, and don't glue the cells anywhere but at their centers. The cells and the panel they are mounted on will expand, contract, flex and warp with changes in temperature and humidity. If you glue the cells too tightly to the substrate, they will crack in time. gluing them at only one point in the center allows the cells to float freely on top of the substrate. Both can expand and flex more or less independently, and the delicate solar cells won't crack.

Next time I will do it differently. I will solder tabs onto the backs of all the solar cells. Then I will glue all the cells down in their proper places. Then I will solder the tabs together. It seems like the obvious way to go to me now, but I had to do it the hard way once to figure it out.

Here is one half panel, finally finished.

Step 8: Interconnect the strings of solar cells and test the half panel

Picture of Interconnect the strings of solar cells and test the half panel
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Here I used copper braid to interconnect first and second strings of cells. You could use solar cell tabbing material or even regular wire. I just happened to have the braid on hand. There is another similar interconnection between the second and third strings at the opposite end of the board. I used blobs of silicone caulk to anchor the braid and prevent it from flopping around.

The second photo shows a test of the first half panel outside in the sun. In weak sun through clouds the half panel is producing 9.31 Volts. YAHOO! It works! Now all I had to do is build another one just like it.

Once I had two half panels complete, I could install them in their places in the main panel frame and wire them together.

Step 9: Install the half panels in the box

Picture of Install the half panels in the box
Each of the half panels dropped right into their places in the main panel frame. I used four small screws (like the silver one in the photo) to anchor each of the half panels in place.

Step 10: Interconnect the two half panels

Picture of Interconnect the two half panels
Wires to connect the two half panels together were run through the vent holes in the central divider. Again, blobs of silicone caulk were used to anchor the wire in place and prevent it from flopping around.

Step 11: Install the Blocking Diode

Picture of Install the Blocking Diode
Each solar panel in a solar power system needs a blocking diode in series with it to prevent the panel from discharging your batteries at night or during cloudy weather. I used a Schottky diode with a 3.3 Amp current rating. Schottky diodes have a much lower forward voltage drop than ordinary rectifier diodes, so less power is wasted. Every Watt counts when you are off-grid. I got a package of 25 31DQ03 Schottky diodes on Ebay for only a few bucks. So I have enough left-overs for lots more solar panels

My original plan was to mount the diode inline with the positive wire outside the panel. After looking at the spec-sheet for the diode though, I decided to mount it inside since the forward voltage drop gets lower as the temperature rises. It will be warmer inside the panel and the diode will work more efficiently. More silicone caulk was used to anchor the diode and wires.

Step 12: Run wires outside and put the Plexiglass covers on

Picture of Run wires outside and put the Plexiglass covers on
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I drilled a hole in the back of the panel near the top for the wires to exit. I put a knot in the wires for strain relief, and anchored them in place with yet more of the silicone caulk.

It is important to let all the silicone caulk cure well before screwing the plexiglass covers in place. I have found through past experience that the fumes from the caulk may leave a film on the inside of the plexiglass and on the cells if it isn't allowed to thoroughly cure in the open air before screwing on the covers.

And still more silicone caulk was used to seal the outside of the panel where the wires exit.

Step 13: Add a plug

Picture of Add a plug
I added a polarized two-pin Jones plug to the end of the panel wires. A mating female plug will be wired into the charge controller I use with my home-built wind turbine so the solar panel can supplement it's power production and battery charging capacity.

Step 14: The completed panel

Picture of The completed panel
Here is the completed panel with the plexiglass covers screwed into place. It isn't sealed shut yet at this point. I wanted to wait until after testing it because was worried that I might have to get back inside it if there were problems. Sure enough, a tab popped off one of the cells. Maybe it was due to thermal stresses or shock from handling. Who knows? I opened up the panel and replaced that one cell. I haven't had any more trouble since. I will probably seal the panel with either a bead of silicone caulk, or aluminum AC duct tape wrapped around the edges.

Step 15: Testing the solar panel

Picture of Testing the solar panel
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The first photo shows the Voltage output of the completed panel in bright winter sunlight. My meter says 18.88 Volts with no load. That's exactly what I was aiming for.

In the second photo I am testing the current capacity of the panel, again in bright winter sunlight. My meter says 3.05 Amps short circuit current. That is right about what the cells are rated for. So the panel is working very well.

Step 16: Using the solar panel

Picture of Using the solar panel
Here is a photo of the solar panel in action, providing much needed power on my remote Arizona property. I used an old extension cord to bring the power from the panel located in a sunny clearing over to my campsite under the trees. I cut the original ends off the cord and installed Jones plugs. You could stick with the original 120V connectors, but I wanted to make sure there was absolutely no chance of accidentally plugging the low-Voltage DC equipment into 120V AC.

I have to move the panel several times each day to keep it pointed at the sun, but that isn't really a big hardship. Maybe someday I will build a tracking system to automatically keep it aimed at the sun.

More details on the electrical system can be found on my web site at http://www.mdpub.com

Step 17: Counting the cost

Picture of Counting the cost
So how much did all this cost to build? Well, I saved all the receipts for everything I bought related to this project. Also, my workshop is well stocked with all sorts of building supplies and hardware. I also have a lot of useful scrap pieces of wood, wire and all sorts of miscellaneous stuff (some would say junk) laying around the shop. So I had a lot of stuff on hand
already. Your mileage may vary.

Part                       Origin               Cost

Solar Cells                Ebay                 $74.00*
Misc. Lumber               Homecenter Store     $20.62
Plexiglass                 Scrap Pile           $0.00
Screws & Misc. Hardware    Already on hand      $0.00
Silicone Caulk             Homecenter Store     $3.95
Wire                       Already on hand      $0.00
Diode                      Ebay                 $0.20+
Jones Plug                 Newark Electronics   $6.08
Paint                      Already on hand      $0.00

Total                                           $104.85
Not too bad. That's a fraction of what a commercially made solar panel with a comparable power output would cost, and it was easy. I already have plans to build more panels to add to the capacity of my system.

* I actually bought 4 lots of 18 solar cells on Ebay. This price represents only the two lots that went into building this panel. Also, the price of factory second solar cells on Ebay has gone up quite a lot recently as oil prices have skyrocketed.

+ This price represents 1 out of a lot of 25 diodes I bought on Ebay for $5.00.

You can learn more about this project and my other alternative energy projects, including my home-built 15 Watt solar panel, my home-made wind turbine, and my biomass gasifier on my web site.
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Edbed1 month ago

cool

SeosmartS3 months ago



howdy, your
websites are really good. I appreciate your work.

Home Prices In
Gilbert Arizonahttps://youtu.be/iHMkAQC_cmg

rexnamo6 months ago

I made it but the cells easily crack and also it makes it a bit difficult. The heat inside the cabinet bends the cells and to prevent further damage I removed it from solar. How to prevent it. I am using acrylic sheet to make window.

hassan.deq6 months ago

Please help me.
1. where can i get this solar cells ?
2. What is the difference between mono crystalline, poly crystal and multi-crystalline?
3. How many pieces of solar cells are there in 1 kg f it?

tinker2343 years ago
could i harvest solar panels from garden stakes and solar toys

You *could*, but they won't be very powerful and you will need a very large quantity. Also, if they aren't all the same type, putting them in series will only give you as much current as the smallest one.

rashaism11 months ago

thank you for this very nice project...

I want to ask you if i want to buy the solar cell what must be its power?

ppereira141 year ago

I was looking for a higher capacity Solar System (400W or more). I found a really nice instructable. Heres a linkhttp://www.instructables.com/id/Apartment-Solar-System/

nepwk3 years ago
Excellent project. HOWEVER, if you try to build this keep in mind that you will NOT get 60 watts out of it (as claimed by the author) using the cells that this author used.

The author claims it produces 18.88 volts OPEN CIRCUIT with NO LOAD. No problem there. This is pretty much typical for 36 cells in series.

The author claims it produces 3.05 amp SHORT CIRCUIT CURRENT. Again, no problem as this is typical of this size solar cell.

And it's true that volts x amps = watts.

However, you can not multiply 3.05 amps short circuit current by 18.88 open circuit volts and come up with ~60 watts (57.584 watts to be exact).

Why?

When the solar panel is short circuited you get 3.05 amps at ZERO volts. 3.05 x 0 = ZERO WATTS.

When the solar panel is open circuit you get 18.88 volts at ZERO amps. 18.88 volts x 0 amps = ZERO WATTS.

What you need to look at is the IV curve (I=current in amps and V=voltage in volts) for the solar cell being used. When the solar panel is producing the maximum amount of power that it can produce the voltage will ALWAYS be LESS than the open circuit voltage and the current will ALWAYS be LESS than the short circuit current. Do NOT expect to see anywhere near the 60 watts claimed for this solar panel if you decide to build it. Depending on the exact solar cells that you get, expect to see more like 30 to 40 watts under load and you will not be disappointed.

This author makes the same error in his "How I built a folding 15 Watt Solar Panel" instructable where he also multiplies SHORT CIRCUIT CURRENT by OPEN CIRCUIT voltage and comes up with 15 watts for 40 cells (or 2.67 watts per cell) which is impossible considering that those cells are only capable of producing ~0.25 watt per cell under IDEAL conditions and more like 0.15 watts per cell under typical conditions.

Again, NICE PROJECT but the author REALLY needs to correct the mis-information he is posting in these instructables and on his website.

you are absolutely incorrect. by ohms law itself. it takes one volt of pressure to push one current of power through one ohm of resistance. therefore 3.05 amps requires at least 3.05 volts. but the ultimate truth you are probably looking for is that direct current CANNOT, WILL NOT, and NEVER WILL BE measurable in watts. to this very day, and i fear, for quite some time the difference between AC and DC will be misunderstood by even PHD holding electrical engineers. i am currently part of a project to rectify the problem. but fighting academia is harder than one might think, unless you consider how many theses for doctorates that would be nullified are taken into account. good job on the instructable. and never trust a PHD. ;)

graphixv nepwk3 years ago
Good comments. There are way too many Pie-In-the-sky claims made by people who make panels. And, way too many claims you can save 75% off factory panels by making them yourself. I blame all this on the second hand, B solar cell peddlers out there. They try to convince people they can make a solar panel for pennies on the dollar by purchasing their junk cells. Only after purchasing, the buyer finds out that the panel cost is going to be much higher unless big corners are cut.
welfner1 year ago

This came up again in Instructables, I guess this video was made almost 4 years ago. Today you can find solar panels at less than $1 a watt, some as cheap as 60 cents a watt. cheaper than they can be made and they can live outside...

DayBowBow2 years ago
So how many total diodes were used on this?
useful12 years ago
Hi there,

I just wanted to say, I built 20 solar panels because of this instructable, so thank you. It helped me a great deal understand about solar power and saving real cash from buying from the electrical company.

Currently on top of my house, there are over 20 panels I made by hand using local materials here in asia using your specs. I bought solar cells from ebay marked as B grade or A grade, almost exact replicas of the images on this instructable. It took over 2 years to complete them (at least for me).

There are a few caveats I ran into while building the first panel, which I shortly learned then fixed on the 2nd panel. Then more problems happened on the 2nd panel until what I have is my 20th panel.

1) Rain. It rains about 6 months of the year. I used silicon caulk bought from Home Depot., to seal the panels as per your instructions. However, water eventually made it through the wood, regardless how many layers of external paint I applied to each panel and upped the amount of silicon to seal.
To solve the problem now, and in the future, I read somewhere else that people bury there solar cells inside clear epoxy. That did the trick. I no longer had problems with water seeping in. However, it did dramatically increase the cost of making the panels. Resin or Epoxy is not cheap even in big quantities.

2) Plexi-glass didnt cut it. It immediately warped the the shape and size and domed. I replaced the plexi-glass with standard window glass cut to size.
Due to the other 6 months, where it doesnt rain, nothing but pure hot sunlight.

3) Amperage is dropping over time. My panels are giving me an open voltage between 18V and 21V. Under load, the voltage drops to around 13.7. (when everything is all connected) The amperage is dropping on some of the panels
The amperage varied when first built gave around 1.8 amps to 2.4 amps.
Now each panel 2 years later, dropped to 1.1 amps to 1.6 amps.
That's a pretty big drop in total amount of wattage. Its also a huge red flag to anyone building their own panels.

4) Repair. If you ever need to repair the cells, you're going to need to open up the panel. For areas that doesnt have extreme weather, resin/epoxy is probably not necessary. But at first, one of the instructions was to glue
the solar cell to the wooden backing, so that it stays put. I'm sure this instructable, never thought about having to repair the panel itself. But gluing the cell to the wooden backing is an absolute no-no. Not only is it frustrating hard to remove, it is almost impossible ( at least in my own experience )

Anyways, thanks for the instructable. Im not sure if DIY is a good way to go now, now that I learned more about the process and building them. The factory stuff bought from the store is already pre-made for outdoor environments. The savings between a panel and building your own these
days is negigible.
robbytesla2 years ago
I have found that using a heat gun (very similar to a hair blower) in the low heat setting can do the trick of cleaning off the residual wax from the cells while athe same time using cotton cloth or paper towels to wick out the molten wax.
timmi6 years ago
Hello, could you possibly expand a little bit more on how you joined the strings of cells. Thanks
msavoy1 timmi3 years ago
http://www.youtube.com/watch?v=5Zy3ELxwdtE

this video goes into great detail
msavoy1 timmi3 years ago
http://youtu.be/5Zy3ELxwdtE

this video goes in depth with the whole process
I'm having problems with this as well.
triumphman3 years ago
Exacty, still no lasting, affordable way to get electricity from the sun! When will this happen ? Not in our lifetime! So solly, cholly!
davecardin3 years ago
Could you show where you hooked up the tester to the wires? Did you just touch the electrode to each of the prongs on the plug?
Nick Dolan3 years ago
And this is just the same copper wire from earlier?
working_it3 years ago
You need to use a low iron glass.
Plastic of any kind will fade in time.
You will also need to pot the solar cells in a special silicone that
is way more translucent then regular silicone.
Otherwise the light is really not getting in.
If your solar panel gets way hot, you will need to spray the underside
to get the wattage back up...heat kills the efficiency of the cells.
graphixv3 years ago
New factory 100 watt Solar panels are currently available in the $200-$250 range. I wouldn't go the DYI route unless you are planning to do an assembly line quantity of panels.

The cost to self-make a 100 watt panel is not that much different than buying a panel if you build it correctly. You also have the possibility of running into bad cells, user error and poor materials.

I would only go the DYI route if you’re building a huge system like 1000 watts. You could save 50% over factory panels building a lot of them, then again you may get poor panels. Check Ebay and Amazon for new panels. And remember, don’t buy small panels <50 watts, the cost per watt goes way up due to labor and other materials which are involved in making a panel of any size.
mdavis19 (author)  graphixv3 years ago
The situation was different 3 1/2 years ago when I originally posted this instructable. Anyway, there will always be people who prefer to roll their own, no matter how low the price of commercially made units go. If you aren't a maker, you wouldn't understand.
I agree. I was just making sure people were updated. I also bought some cells to make a panel not knowing at the time what the real cost would be and ended up buying a panel instead. If someone goes the DYI route, they may want to spend another $2 and install some dypass diods to make their panel shade resistant.
jcvillar3 years ago
Nice construction, but I worry that you are not using an encapsulant, such as SylGard, to prevent degradation of the cells.
RisingSun3 years ago
If I was your panel I would be afraid of a critter jumping or climbing on me, although I don't know what your place is like. Really cool instructable btw
gneal4 years ago
Thank you so much for this instructable. I actually built a solar panel using your instructions and it works great. I hooked it up to my DIY electric fence and it works perfectly. My dog knows what its boundaries are now.
Valence_46 years ago
Another important thing to greatly improve the panel's efficiency: Solar cells do provide a 0.45volt FORWARD voltage when lit by sunshine but will act as a REVERSE biased diode if unlit. So if a leaf falls on one cell of your panel, the overall efficiency will be HIGHLY reduced by the unlit cell that will absorb a high reverse voltage. This will not only highly reduce the panel's efficiency but may also damage the unlit cell if the panel is loaded. To prevent this, i strongly suggest you to buy 3 ampere shottky diodes (1N5820 for example), one per cell, and solder them un PARALLEL with each cell. The polarity is important. For that, use one cell, put it under sunlight and using a voltmeter, test which side is positive and which is negative. If i remember well, the top side is negative. Then, solder long bare wire (AWG24 will do the job) to each end of the diode and then, solder the bare wires onto BOTH tabs of the solar cells with the CATHODE (banded) side on the POSITIVE side of the cell and the ANODE (no band) side on the NEGATIVE side of the cell. On normal use, the diodes will be REVERSE biased and will have NO EFFECT on the overall panel's efficiency. But in one or a few cells are shaded either by a leaf, a bird or a tree's shade, thee diodes will start to conduct as the solar cell is reversed biased. This way, the whole panel will continue to generate power and the shaded cell(s) will be protected by the diode that will limit the cell's reverse voltage to less than 1/2 volt. I suggest Shottky diodes rather than ordinary 1N5401because of their lower forward voltage (typ. 475mV) compared to classic PN junction diodes (1 volt Vf).
Or you can Buy more solar sells to provide power for fans to blow them off BTW he said his place is windy all the time.
so basically you're telling me that if a large leaf shades 1 solar cell in a series of 36 the voltage drops to 0 becauce it is essentially breaking the circuit that would be expensive to buy 1 diode per cell how come no one else mentions this
I highly recommend doing this as well. All those cells in series are all affected if one of them is unlit. The current drops to the one cell that is unlit (0 amps).
raja6814 years ago
what is a good price for 120 of these
ezrablu4 years ago
AWESOME instructible...THANK YOU for sharing this with the world who would otherwise be prisoner to purchasing panels for big bucks or not being able to afford them all.
My thought exactly. I want to build a solar system, but can't afford the high cost of panels.
sspence6 years ago
I thing something less susceptible to moisture (the peg board we get is really pressed paper layers and delaminates easily) would last longer. Just a thought.
What do you think is better than peg board?
white melamine. which is similar to pegboard, but it seems to have more binder material pressed into it. It costs a little less than pegboard (if I recall) and is in the same aisle of your home improvement store.
 Marine plywood maybe? Or a sheet of plexiglass (expensive but durable).
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