Many electronics circuits and projects for learning in simple ways.

Outdoor solar lights circuits

My son needs lighting around the house at night. But that point is no AC lines, it’s hard wiring. We happen to have the 12V battery, LED lamps and Solar cell. Thus was born the idea to create the Outdoor solar lights circuits. It saves electricity costs. The LED lamp will light up the night itself, and closed at lunchtime. The charging power from the solar cell to the battery.

We use the 12V 2.5Ah battery and The LED lamp 12V 3W. It can be used for about 5-8 hour. The solar cell charging is 12V 10watt. While very light, a voltage of approximately 20V at current 0.6A can use the battery.

In this solar led light circuit project, I and He together to create.
1. At night, LED lights because of the energy from the battery.
2. Lunch, the LED will turn off and the energy from the solar cell will charge to the battery fully.


In Figure 1 as the schematic circuit diagram. We add D1 to determine the current battery charge only one way.


And Figure 2 we apply the relay when the day some the current flows through the coil of the relay with D2.

As Figure 3 the complete circuit diagram

Making the contact C to NO, so no current flows through the LED. But the dark without electricity from the solar cell to coil cause the contact C to NC to connection the current so flow to LED light up. D2 is protector the current feedback from the coil relay to the solar cell.

Then we make it please see below.
Figure 4 install the solar cell

Figure 5 We hold the solar cell on the wood.

Figure 6 the connection and test battery charger

Chayapol is making Outdoor solar lights circuits
Figure 7 He is wiring his super solar!

Figure 8 He is showing his projects.

Figure 9 next viewing

We installed this project to actually use it.





Automatic LED solar light 2

My son and I build the Automatic LED solar Light is version 2. It has a higher performance, is brighter as Figure 1 compares the version 1 (left) and the version 2 (right). Because we use LED grow larger, but use a 12V battery as the original.

Figure 1

DC current measurement techniques
My son wants to know how many current the 12V LED lamp use? So I teach measuring the current of the devices. It’s easy but be careful high current, might hurt your meter.

How to
First of all, set to DC current range. Then, connect the wires in series to load. Next, apply current to the circuit.
As Figure 2 we test the 12V relay coils,it can read: 0.03A

Figure 2

And next,he test the LED lamp is 0.330A ,as Figure 3
Figure 3

To see that the current of LED is very high. When we use the 12V 2.5Ah battery, works just 8 hours only. It should be set to a light sensor, to control LED brightness, when less light only. For example LED lights at approximately 19.00 to 5.00.

I designed the automatic light switch, as Figure 4 the complete schematic circuit diagram.

Figure 4

More parts you need
Q1…..9013 NPN transistor
R1…..1K 0.25 watts Resistors
R2…..10K 0.25 watts Resistors
VR1….50K potentiometer
LDR…..Light sensor
RY1……12V relay
D1,D1…..1N4007 (1A 1000V Diode)

VR1 is used to adjust light sensitivity. And another circuit like version 1.

How to assemble
This project has few parts so without PCB layout as Figure 5 He connects them directly.

Figure 5

and next step drill the plastic box as Figure 6 to use the wires in the hole.


then, install it in the box Figure 7 and on the wood as Figure 8

Figure 7

Figure 8

And next step connects more wires to the battery as Figure 9

He shows it in Figure 10 when complete assemble.


And later we install it in our garden. Everyone is happy.
solar install

install the solar cell system

The solar cell 10 watt connecting

This Post Has 12 Comments

  1. Excellent idea. Please keep sharing yours and sons solar ideas with us

  2. Superb.

  3. Hi Chayapol Well done for such an ingenious design both electronic an mechanical!
    The only thing i would point out is that there is no in-line fuse on the battery, so if there was a problem everything would be at the battery’s maximum current potential Eg 100Amps even though at this current the battery voltage would drop significantly.

    But looking at it another way as well as a light it would make a nice heater!

    Please carry on inventing things i love to see tour things. I was probably about 8 or 9 years old when i started with electronics


  4. Hi Paul,
    Thanks you feedback.
    It’s nice Fuse protection battery explosion.

    I am also love DIY electronics same you.


  5. I am puzzled why you are using a relay, as this will usually draw more power than the LED, possibly a Mosfet would be drastically more efficient ?

    Otherwise, keep up the good work

  6. Hi William,
    it is good idea next project i will use mosfet.

  7. I learned electronics as a child instead of TV and comic books. I am old man now. Still love electronics. Became eng. keep up the good work. English will come to you.
    Jim USA

  8. Hi Jim,
    I am very happy that hear you sound. I tech my son with Electronics,too. He study with homeschooling.

  9. This is a great project. I want to know that can i use 5 watt or 15 watt solar panel instead of this one without any change in circuit.


  10. Sir..i want make 1w led solar lantern .ple send me to create led solar lantern,

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