This guide will show you how to build a charger that uses sunlight to charge a 12V battery, like the ones in cars or some toys.
Normal chargers need an outlet, but this one uses a solar panel instead, so it is great for places without electricity.
We will call this charger a “Solar Power Battery Charger.”
It uses the suns energy to charge batteries in things like phones, laptops, car batteries even lamps and fans.
These chargers do not plug directly into devices.
They have a battery that stores the solar power, like a little juice box.
This stored power is then used to charge your devices through a special part called a capacitor.
Ready to learn how this solar charger works and how to build it?
Let us look forward in this article.
What is a Solar Battery Charger Circuit:
A simple solar battery charger is a device that uses solar energy to charge rechargeable batteries.
The basic idea is to capture sunlight using a solar panel and convert it into electrical energy to charge a battery
Solar Battery Charger Circuit Diagram
Components List:
| Component | Description | Quantity |
|---|---|---|
| Resistors (all 1/4 W CFR) | ||
| 220Ω | 2 | |
| 680Ω | 2 | |
| Potentiometer | 2k | 1 |
| Capacitors | ||
| Ceramic 0.1µF | 1 | |
| Semiconductors | ||
| Diode | 1N5402 | 1 |
| Schottky Diode | 50V 3A | 1 |
| Integrated Circuit | LM317 | 1 |
| Solar Panel | 18V 1A | 1 |
Circuit Description
When sunlight irradiates the solar panel the photovoltaic component which is the solar panel cell, transforms the solar energy into electrical voltage.
To regulate the voltage, we employ the LM317 integrated circuit IC along with a potentiometer for voltage adjustment.
The LM317 formula for calculating the output voltage is as follows:
Output Voltage Vout = 1.25V × (1 + (R2 / R1))
where:
- Vout is the desired output voltage.
- R1 is the resistance connected to the adjust pin of the LM317.
- R2 is the resistance connected between the output and adjust pins of the LM317.
Step 3: Reverse Supply Protection
To prevent reverse supply, a 3A 50V Schottky diode is used.
The diode equation relates current and voltage in a diode and can be expressed as:
I = Is [V / (enV/n.Vt – 1)]
where:
- I is the diode current.
- Is is the reverse saturation current.
- V is the diode voltage.
- n is the ideality factor (typically around 1 for Schottky diodes).
- Vt is the thermal voltage (approximately 0.026 V at room temperature).
- These formulas are fundamental for understanding and calculating the voltage regulation and current flow in the solar power battery charger circuit.
The final output is a 12V supply, which can be used to charge various electronic devices.
This voltage is suitable for charging a wide array of gadgets.
How to Build:
Connect the positive (+) and negative (-) terminals of the solar panel to the input terminals of the LM317 voltage regulator.
The solar panel should generate a voltage higher than the desired output voltage.
Connect the output pin of the LM317 to the positive terminal of the capacitor.
Connect the negative terminal of the capacitor to the negative (-) terminal of the battery.
Connect one terminal of the potentiometer to the adjust pin of the LM317.
Connect the other terminal of the potentiometer to the negative (-) terminal of the capacitor.
The middle terminal of the potentiometer can be used to fine tune the output voltage.
The LM317 formula mentioned above helps you calculate the resistor values for your desired output voltage.
Connect the anode side of the Schottky diode to the positive (+) terminal of the battery.
Connect the cathode side of the diode to the output terminal of the LM317.
If you want to include a charging indicator, you can add an LED with a current limiting resistor in parallel with the output terminal.
Secure all components on a breadboard or a printed circuit board PCB.
Make sure all connections are properly soldered and insulated to prevent short circuits.
Connect the solar panel to the circuit.
Place the solar panel in direct sunlight.
The circuit will charge the battery according to the voltage settings on the LM317 and the solar panels output.
Application and Uses
The “Solar Power Battery Charger” has a range of applications and uses, including:
Charging electronic equipment, devices, and gadgets such as mobile phones, laptops, and more.
Providing a convenient charging solution while traveling especially in situations where access to conventional electrical outlet is limited or unavailable.
In conclusion, the solar power battery charger is an innovative solution for harnessing renewable energy from the sun and converting it into a reliable power source for charging our everyday electronic devices.
By following these construction details and understanding the working mechanism, you can create a practical and eco friendly charging solution for your technological needs even when you are on the go.
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