We can use it in smart way.
This Simple Solar Light Circuit charge battery in day and glow LED at night.
There is no need of switch and no need care.
It is just simple and magic from sun.
Circuit Working:
Parts List:
| Component Name | Quantity |
|---|---|
| Relay 12V SPDT | 1 |
| Solar Panel 18V 10W | 1 |
| Diode 1N4007 | 2 |
| LED Lamp 12V | 1 |
| Battery 12V 2.5Ah | 1 |
During daytime, the solar panel gives 18V DC output.
This voltage passes through diode D1 1N4007 and charges the 12V battery.
At the same time the relay coil also gets power from the solar panel.
The relay pulls its contact to the NC (Normally Closed) position, so LED lamp is OFF during the day.
When night comes the solar voltage drops to zero.
The relay releases, switching contact to the NO (Normally Open) position.
Now the battery connects to LED lamp, turning it ON automatically.
So the LED glows at night and turns OFF in the morning.
Formulas with Calculations:
Below are the general formula for Simple Solar Light Circuit:
Solar panel: 18V, 10W
Power = Voltage × Current
10W = 18V × I
I = 10 / 18 = 0.55A
Battery: 12V 2.5Ah
Charging time = 2.5Ah / 0.55A = 4.5 hours (approx.)
How to Build:
To build a Simple Solar Light Circuit follow the below connections steps:
- Take all the circuit parts as shown in above diagram
- Solar cell positive connect to D1 anode
- D1 cathode connect to NC relay coil pin & battery positive
- Solar cell negative connect to ground (common)
- Relay coil one end connect to D2 diode
- And Relay coil other end connect to ground
- Relay common pin connect to cathode of LED lamp
- And anode of LED lamp connect to GND
- Battery negative goes to GND.
Conclusion:
This Simple Solar Light Circuit is good for small garden or for emergency light.
It works automatically, saves energy and is easy to build with few components.
It is easy to build for beginners.
References:
Solar panel as light sensor to switch a battery and LED circuit