# Free Energy From LEDs

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## Step 1: Round Up Some LEDs!

First you'll need to get however many LEDs you want. You'll then want to connect the LEDs in a series, leaving a positive and negative wire.

NOTE: This works with any LEDs, but I have found that it works best with Red LEDs

## Step 2: Go Towards the Light!

Then you'll want to get a light source (lamp or daylight) and put the circuit right in the strongest part of the light.

## Step 3: It's As Simple As That!

Just hook up the wires to a voltmeter and you'll see how much power they are generating. I was able to produce 1 volt just by using 3 LEDs and a bright lamp.

(As if you couldn't tell, this is my first ible, so some advice would be greatly appreciated)

Inspiration for this project and more information on how this works can be found at https://www.instructables.com/id/Better-LED-as-light-sensor

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## 14 Discussions

An LED is a very poor solar cell in the same way that a solar cell is a very poor LED. Both are optimized for their primary function: to emit light OR to convert light ot electricity. Both work in the opposite way as well, but apart from studying the underlying physics there is nothing to be gained from using LEDs as solar cells.

Get a cheap solar-powered garden light for EUR 0.50 or an equivalent amount of money from your nearest hardware store and you get an LED and a useful solar cell module for your projects.

I only have 4 LEDs, so I have not been able to generate enough current to power something.

I'm afraid even with 4,000 LEDs you would struggle to actually power something. Voltage and Current are interdependent. A large voltage does not mean a large current. Power in terms of Watts is represented in terms of Voltage x Current. You would be much better off with actual solar cells. Using the LED as a light sensor is a good use for this phenomonon.

I think you can use powe LED (1W) to achive more energy!

Lean04, you do realize a simple schematic of this would be an LED?

since you´ve asked for advice i was suggesting a schematic so you have a more complete and friendly instructable, and it wouldn´t be a simple LED, because you´d be showing a lots of simple LEDs in series (in this particular case) for those DIYers that are new to electronics...

The LEDs are acually in reverse (anode on negative and cathode on positive connector). The current is there, but it is somewhere between nano- and microamperes.

The current that is generated could be used to indicate sunlight (or the absence of it) as shown in this schematic ( http://www.dieelektronikerseite.de/Pics/Tricks/Dioden-Sperrstrom%20S01.GIF) , the D1 is the diode in the way you use it.

Your method of producing energy is barely enough to keep a microcontroller in low-power-mode, but not using it to make any program run.

With an array of 1000 LEDs in parallel you could produce about 1-10mA which would be nothing fancy, if you think of the costs compared to a little solar power module.

Most of the energy you put into the LEDs (the 100W lamp) is wasted, because of the less energy you get out
P = 1V * (ca. 1-10µA) = 1-10µW.
Even if it would be more current (for example 10µA per LED) the output of power would still be around 30-50µA with 3-5 LEDs

I would suggest a net of lemons to build a lemon battery or some other chemical ways (vinegar and copper) which produce more power than the LEDs in reverse.

Maybe placing some schematics would help and measuring the current too

that's interesting, but maybe a picture of the multimeter with output voltage will explain better the goal..

So, you're using LEDs as tiny solar cells?

Have you powered anything with them yet?

I was unable to detect any amps with only 3 LEDs.

Nowhere near enough to be useful, unfortunately, since they aren't designed to do this. A similarly-priced solar panel typically outputs far, far more voltage and current than a bunch of LEDs can, and isn't likely to decide that it wants to emit light instead of generating power if there's any surplus power in the system, such as a backup battery.