Picture of Recycled Solar Power
This is about a Solar Power Plant made from recycled parts. It is a work in progress. It all started at the landfill where someone next to me was throwing away 11 solar garden lights. I had 9 at home from garage sales. I had an old picture frame and some plywood and paint. I had to buy 4 diodes from radio shack. I started by taking all the lights apart and using the solar cells. I saved the circuit boards and LED's for future projects. The plastic globe made nice little hot caps for the garden.
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Step 1:

Step 2:

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I painted the board with some old house paint. I soldered 5 in a row pos. to neg. I think that 4 would have been OK I will know when I get done. Each set is putting out 22 volt in good sun.

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I mounted the cells with a little hot glue then soldered a diode to the pos. on each set and into a splice on a single cord. Next I spliced all the neg. ends to a single exit wire. I dabbed a little hot glue over the solder joints to keep everything in place. I hot glued the picture frame over everything leaving the bottom un glued for a little ventalation.

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The first test. Over 22 volts on a winter day. Tried it vertical and horizontal. I have no idea of how many watts.

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I cut some scrap plywood and nailed and glued it to the sides. I cut them at 60 degrees for Washington state.

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I used the globes for hot caps out in the garden.
Awgdwg21 days ago
What size diodes?
What size solar panels. Mine only put out about 1.4 volts each

Actually, 4 diodes was the correct choice. They serve 2 purposes. 1, they keep the array from discharging the batteries when there is no light, and 2, they keep a bad cell in one of the lines from stealing the current from the others. The loss is exactly the same since each of the 4 paths only pass though 1 diode. Using 4 also lets you get away with cheaper diodes since each diode only has to handle 1/4 of the total current. If you use 1 diode it has to handle the current from all 4 arrays. With 4 diodes, you actually lose less power. Power loss is the the internal resistance of the diode times the current squared. So for example, lets say the internal resistance of the diodes is 1 ohm and each of the legs provides 1 amp of current. With 4 diodes, your total loss would be 1 ohm X 1 amp x 1 amp = 1 Watt (per diode) for a total of 4 watts loss. If a single diode was used you would have 1 ohm x 4 amp x 4 amp = 16 watts loss.

The charge controller will tell you the wattage.

is there a video for this? i understand these types of things better when I can see it being done. And I need to build one of these.

spylock9 months ago

Good job on the solar by the way.Ive got many cells from old garden lights,and was planning on doing something like this,being that store bought panels are so high,thanks to oil companies,and other like minded crooks.Some of mine are different shapes,so I will see what I can come up with.

spylock9 months ago

Have you still got the scooter?The motor may make a hellova nice wind turbine,depending on which motor you have.

goldamazon11 months ago

the one concern I have with putting the inverter and the battery in an old sewing box like that is the fact that the inverter needs to be kept cool and the battery when it's charging gives off a small amount of corrosive gas. Or a large amount if your battery is bad. So if your putting them in a small box so close together you might wind up with corroding the inner workings of your inverter by the gasses from the battery or overheating the inverter because not enough cool air.

Macattacku1 year ago
Those batterys probably cant hold a good charge anymore anyways. From what u said they have been sitting at 9 volts. They are probably badly sulfated. When you put a heavy load on it the voltage will drop like a rock.
jimbo132 years ago
if you tested it with a volt meter and no load connected then that is open circuit volts, so real volts with a load would be about 18 volts.
Gelfling62 years ago
I've done this with a bunch of much older solar lights.. these had a small 6V Gel Cell, (which usually was well cooked/dry) and a BIG 4"-Square solar panel which would generate up to 8V. (never really got the chance to measure the mA output.) I used to run a 9V transistor radio off one two in series.. No ideas where the heck I put it, though.. Yes, these are totally reusable! I almost had a fit when someone dumped a whole bunch of these style lamps off at the local recycling center, and before I could collect more than 3, the town employee grabbed the whole bunch, into a pail, and put them in the electronics bin. (which made them Hands-Off.. The town collects electronics for (they say) payment from the recyclers. (if they think they'll make millions on the gold, I'd hate to see how much they'll spend on the excess scrap they can't..)
Nice Up-cycling! One tip to save you some money on the next one. You don't need a diode on all runs. You only need one at the end after you combine all the circuits. It is all you need to keep the battery from draining.
divudi24 years ago
yes, formula is very much correct
yogadavid4 years ago
Could you please tellme what Diod you used. Thanks for instructable. I have quite a few garden lights and there are very few instructables on using garden pannels for arrays.
aleutianwind (author)  yogadavid4 years ago
Hi I don't remember what the diodes were. I got them at radio shack. You only need one for this size project. I found out I was using too many and they used too much power.
watts=amps x volts I believe
shadow47424 years ago
im sorry i didnt get that last part, could you repeat that?
Nerdz5 years ago
You may only need 1 blocking Diode, not a total of 4. Using 4 Results in a loss of power. Assuming you used silicon diodes, thats 2.8V Loss. At High Currents it could result in a few Watts of power Loss from your panel.
killroy5 years ago
I have the same question as koulis1 and jimsss what diode did you use and what was the voltage of each solar cell from the lamps.
aleutianwind (author)  killroy5 years ago
Hi. I have taken this panel apart and added the parts on to a piece of plywood with a big mess of other solar cells i have collected and a recycled 8-D battery.  The diodes came from radio shack and were cheap. I can't find the package and don't remember the size. Most of the wire was from old light cords. The inverter was to large for those batterys, a 100 watt cig.lighter inverter would be better and could just be plugged into the socket. The voltage was around 19 to 23 per string of 5 cells so i would guess they average out around 4 each.  Oh Don't use hot glue! What was i thinking, By august the rows had sagged in the middle.
hancer5 years ago
koulis15 years ago
I have the same question as jimsss. What diode did you use ?
jimsss5 years ago
what diedo s did you use
mattccc5 years ago
i was thinking of this idea too
FeedTheGrid5 years ago
Well done. I like the hot-caps in the garden, too.
emdarcher5 years ago
I cant believe people where giving and throwing away those solar lights! I wish I had got those kind of neighbors in a way
...very much agreed....
DIY Dave5 years ago
strmrnnr5 years ago
Good Idea. I have another idea for you. If the panals were wired with strong multistrand wire you could mount the panels to a piece of heavy canvas or leather and then you could fold it up and take it camping with you.
julesfl5 years ago
Wonderful project! Recycle the solar panels, cool, and portable!!
Your project is excellent. To find the max watts for your panel, use an ammmeter to measure what is called short circuit current in full sun. Most DVM's have a 10 amp current position on them. Connect the DVM (set on amperes) directly across the output leads of you panel. Multiply the open circuit volatge times the short circuit current to get the max watts that the panel can put out. You will get slightly less than this, as the voltage falls when the panel is loaded.
muzza.wood5 years ago
Hi, This is very interesting and thanks for your effort. I have a question about the wiring. What sort of diode would it be? and what kind of cord was it spliced into? Thanks ./muzza
PKM5 years ago
I have no idea how many watts

A low-power incandescent lightbulb is a convenient resistor that you can use for measuring power. Connect the panel to the lightbulb, then measure the voltage across the lightbulb (multimeter in parallel) and the current flowing through it (multimeter in series), then multiply the two together. I would expect a few watts from the size of your panels- the average garden light solar cell seems to be rated at 150 to 200 milliwatts, so 20 of those could provide 3 or 4 watts in good sunlight.
Lftndbt5 years ago
LoL, here lies the death of the solar garden light. People expect them to be missing in the morning. I sell solar garden lights. For some reason I have never thought to harvest the solar panel out of them, before throwing the damaged ones out. I will be sure to follow your I'ble once I can get some.
chichimus5 years ago
Thats Great. I was thinking of the same thing today while cleaning out the garage :) I am going to ask around work if anyone has any defunct lights.