This is a small DIY Solar Battery Charger Circuit project, which charges one 3.7V lithium battery using sunlight; also we can use solar cell, TP4056 charger board, one diode, one switch and one boost converter module..
This circuit make 5V power for battery and mobile charging.
Graph for lithium battery charge over time:
The above graph show how lithium battery charge over time.
At start the battery take high current and voltage go up slowly, this is constant current stage.
When the voltage reaches around 4.2 V, the charger holds it steady and gradually reduces the current; this process is the constant voltage stage and when the current drops to a very low value, the charger stops charging and terminates the charge cycle.
Hence, this is how TP4056 or other Li-ion charger work safely to charge 3.7V battery.
Circuit Working:
Parts List:
| Components | Quantity |
|---|---|
| TP4056 Battery Charger Module | 1 |
| 18650 Lithium Battery | 1 |
| SPDT Switch | 1 |
| 1N4007 Diode | 1 |
| Solar Panel 5V | 1 |
| Voltage Booster Module | 1 |
Solar panel make electricity from sunlight and diode stop battery power go back to panel at night.
Then TP4056 board charge the 18650 battery safe and then SPDT switch control charge or use mode.
Also, voltage booster take 3.7V from battery and make 5V for mobile or USB device.
How to Build:
To build a DIY Solar Battery Charger Circuit follow the below steps for connections:
- First, assemble all the parts as shown in circuit diagram
- Next, solar cell positive connect to diode anode and diode cathode connect to TP4056 IN+.
- Then solar cell negative connect to TP4056 IN-.
- Also, TP4056 OUT+ connect to battery positive and TP4056 OUT- connect to battery negative.
- Now switch middle pin connect to battery positive and other side of switch go to boost converter input +.
- Now boost converter input – connect to battery negative.
Conclusion:
To conclude, this DIY Solar Battery Charger Circuit is simple and cheap, as it is good to learn small solar project; also we can use it to charge phone, light or small gadget from sun.
Furthermore, it is safe to use and nice for beginner people.