Homemade LED Solar Lamp




Introduction: Homemade LED Solar Lamp

It's a LED lamp that use the sunlight to turn on, turn off and recharge a power supply (rechargable batteries Ni-Mh)

Here is a little video on instagram with an 8LED Lamp


Also we're going to explain how to make your PCB circuits for this lamp.

If you have any question, leave a comment :) or write to this email: mazetm182@gmail.com
We'll answer you as quick as possible

Made it by:

César Cruz

Iván Trejo



-Solar Cell; 3V-6V 100mAh-600mAh

-Rechargable Battery (x2); AA 1.2V/2200mAh-2500mAh

-Battery Holder

-Battery Brooch

-NPN Transistor (x2) (Model used: 2N2222A)

-Diode (Model used: 1N4004)

-Resistor (x2) 1KOhm

-Resitor (x1) 10Ohm

-Welding (1m)

-Wire (1m)

-Copper Plate (5cmx5cm)

-Permament Maker (Sharpie)

- White LED's (x18)

-Copper Plate ()

Tools & Chemicals


-Minidrill (1/32" drill)

-Ferric Chloride (100mL)


-Solder Station

-Digital Multimeter


Here's a photo of the circuit.

If you want, you can make it first in a protoboard ;).

** Here is how to connect transistors too **

Step 3: PCB Circuits

To adapt the copper plate to the size for the circuit you need do a mark (with a pencil or Sharpie) an area of 5cmX2.5cm in the copper plate, for cut following the marks with scissors or a handsaw ( you can use a mini drill).

To mark the circuit in the copper plate, you need do it with a sharpie or print it on couche paper and, later to iron it on the copper plate, (also you can find here the circuit to mark it WITH MARK in your copper plate).

If you prefer print and iron it the circuit to the copper plate, you might take careful for not burn the circuit and assure that the circuit was patch in the copper plate, after you need put the copper plate in water. After patch or mark the circuit in the copper plate, prepare a little bowl with ferric chloride and water; put the copper plate and shake slowly (more-less from 5 to 10 minutes) ; DO NOT throw it; he ferric chloride is very hard to clean D: ).

When the only thing that you can see in the copper plate is the circuit, you can remove it from the bowl. Later you need clean the copper plate with a little piece of cotton and thinner.

In the images you can see PCB layout, which you will draw with the market or iron it. ;)

Step 4: Soldering

a. When you have already your PCB circuits (out of the ferric chloride), with the minidrill you'll drill each "dot" in the copper lines.

b. When you've drilled all the dots, you will start puting the electronic elements (unless transistors) in their correctly place over the plate

c. Your soldering station must to be hot and must thaw the welding. At this moment, you must to place the tip of the soldering iron near the place you'll solder. After 1/2 seconds you need to close the welding to the tip.

d. When ALL the elements have soldered, you solder the transistors. Because these are so delicates

//If you did not understand me how solder, we recommend you watching videos on YouTube ;)

Step 5: Testing

First, put the solar cell to sunlight. After 5 minutes, connect the multimeter with the terminals of the cell. Turn on your multimeter and position it in Volts. It'll show you the voltage of your cell.

Then, repeat the same but position it in Ampers. So it will be shown the current of your cell.

* * For best results, put the cell where the sunlight is hotter. * *

When the voltage of the cell is lower than 0.7 V, the light will turn on.

Step 6: ENJOY IT!!

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    10 Discussions


    6 months ago

    Awesome post, really very helpful and useful will definitely construct one,
    keep up the nice work.


    1 year ago

    When the voltage of the cell is lower than 0.7 V, the light will turn on. (How does it work do I need to adjust anything to change 0.7 V parameter , what if I want to turn on the light when the voltage is lower than 0.5 V ..?


    6 years ago on Introduction

    So are the two battery cells in series? (maybe I'm failing to see that)


    Reply 6 years ago

    No, there is only one solar cell. I used an 3V/80mA, but depends on how many LED's you will use :).
    Thank you for see our proyect :).


    Reply 1 year ago

    3V 80mA would give you about 15 minutes of life if you figure up the LEDs are running @ 20mA each. that seems like a real short life - very ineffective. what kind of current are you seeing in full sunlight on your photovoltaics?


    3 years ago

    Hi, could I use this with a high powered LED of 3.2 watts? Also, do you have a breadboard prototype of this?


    Reply 1 year ago

    That's going to depend on your voltage- im assuming you are using a high powered LED like an Endor Star or similar MCPCB.

    im simple terms, you would need a power supply of correct voltage and with enough CAPACITY to run the LED(s) effectively. lets take a simple example:

    you have an LED with a forward voltage of 3.5V and you want to run it at 1000Mah, amperage runs a little differently than you are thinking in this situation.

    we have an 18650 battery rated at 3.7V and a capacity of 2000 Mah or 2A that means we would get about 2 hours of bright LED then it would start to fade out. - if this guys pic is correct, than you are going to get about 8 hours at 3A or effectively 24A worth of charging time. so in this case, yes you would be able to run this - although id add additional charging circuit.


    Reply 5 years ago

    yes, but you will need a bigger cell. or a panel solar 10W (5V/2A) each led uses 20mA approx.