# Solar panels and LEDs



## actrisor11 (Apr 21, 2009)

Hi All
I am new to this forum,and with that being said please be easy on me.I have been lurking for some time and decided once again to join and post in a forum.
Now there is a lot of talk about solar panels for charging batteries and leds used as lighting: but has anyone besides me thought of using one as both.Ok let me explain before yall call me a nut. The led is nothing but a tiny p-n junction. When placed in light it will create electricity: And conversely when electricity is applied it will create light. I know this to be true because I have built a solar panel using them.
The panel I have now will recharge aa, aaa, c and d batteries: 
and in the near future I will be expanding it to charge 12 v. deep cycle batteries. Now you may ask what can I do with the led panel that can't be done with solar cell bought already made.
PROS
1. I can expand it as time and money will allow, and to the voltage,amperage I desire. All done by me ( hint save money)
2. The led itself is almost indestructible.Heck you could run over it with a car and not brake it. Can you do that with a silicon cell?
3. Leds are weather proof you just need to protect the connections.
4. Leds are getting cheaper even as we speak.
CONS
1. Time and labor consuming.
2. You must use the same type led through out the panel. Ie: a led rated at 1.8 volts will not work with an led rated at 3.8 volts.
Take a look at my web site and read more on it. east texas home power leave a message and tell me what you think.
Actrisor


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## NaeKid (Oct 17, 2008)

Sounds interesting.

What kind of costs are associated with the LED panel? I just setup an 80watt panel on my camping trailer for under $1000 (including charge-controller that is capable of running upto 240watt of power).

I have a nice electronics-kit that I could use to put the panel together. What kinds of materials are required for the base - does it use wires to join the LED's together or would a large printed-circuit-board do the trick?


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## Canadian (Dec 14, 2008)

I like LED's. Great technology.


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## actrisor11 (Apr 21, 2009)

Red leds cost 25.00 per 1000 cost of 2 and 1/2 cents each. They put out 1.6 volts open circuit.Orange and yellow are a little higher in cost but put out the same voltage at a tiny bit more amperage.My source will give big discounts for large orders say 10,000 or more. The red green and blue blinking leds cost much more but put out much more amperage at .50 volts.
Yes leds do cost more per watt of power but what I am trying to show is how someone can build their own panels.Like a custom panel at x volts and x amps whatever you need. And it can be done as time and money will permit.
Now as far as how they are put together in my panel is 3,000 in parallel to achieve the amperage level I need to recharge small batteries. Then I can put the next 3,000 in series to the first to achieve the voltage I want and son on.You can use a perf board if you want but the cost will eat you up. I use a thin 1/4" pressed board that I drill holes in.I have pics of my panel but don't know how to upload them here yet. Here is a small sample of my circuit I use. 
- ++ -- ++ -- ++ -- +
- ++ -- ++ -- ++ -- +
a wire connects all the - in a line going down the board then a wire connects all the + going up the board so that the + lead is on top and the - lead is on the bottom of the board.I put 3,000 together like this then the next 3,000 in series to them. Now with me using pressed board as the base that mandates that I use a frame with glass to house them against water infiltration. I have some pics on my home sithe if you have time go take a look. They really do work.
Actrisor


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## Viking (Mar 16, 2009)

Here's a great site for calculating what resistor to use for LED's. I used it when I had to repair the speedometer panel indicator lamps due to the printed circuit being eaten up in some areas. Current limiting Resistor calculator for leds


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## NaeKid (Oct 17, 2008)

So, in other words, your 3,000 LED panel cost you $75 for the LED's, plus the panel, plus the base-plate for a guestimated total of $90. That puts out approx. 1.5 volts at 300mA (milliAmp)?

If I rough-calculate the requirement to recharge my series-wired 6-volt deep-cycle batteries, I would need 8 of the panels at 3,000 LEDs (total cost would be 8 panels @ $75 = $600) to reach my 12-volt requirement. Then my amperage would need to be significantly boosted to push power into my camper (at least equal amperage to what my solar-panel puts into it which is ~7-amp hr depending on sunlight).

How many panel-sets of 8 would be required to reach something equal-to what my current solar-system does? My guess is that if it is truely 300mA per panel-set I would need to setup a series/parallel set of 8 x 3 to reach 1 amp and 7 sets of those to reach my optimum 7-amp of power going to my batteries.

Am I correct in my numbers here, or, am I not quite understanding how it all lays out?


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## actrisor11 (Apr 21, 2009)

Naekid,if you are shooting for the voltage to charge directly from the panels then the answer is yes very close to what you have stated.( as far as the voltage needed to charge a 12 volt system which i believe is 14.3 volts )For flooded cell batteries.

The amperage per 3,000 is close to the 300 ma which you stated. But and there is always a but, a 12 volt battery can be charged with 2 of the 3,000 panels.How you may say,by using a Blocking Oscillator circuit.The circuit will step up the charging voltage from the 3.2 volts put out by the panels to the voltage needed to charge a battery.
Now the cost for my panels was 45.00 for the 3,000 leds the other things I used to put them together was free.As I stated my source gives discounts for large orders. I ordered 10,000 leds and the cost for me was 150.00 a 100.00 dollar discount.As far as cost per watt then the silicon cell far out ways leds so they are not cost effective that is not what I have been trying to say.I have been working with leds trying to find ways to use them that most folks don't even think about.Ie: leds as solar cells, leds as grow lights and many other uses.
I hope this answers some of your questions.If you have more then please ask.
Actrisor


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