We can make small IC 555 Solar Charger Controller Circuit.
This circuit checks battery voltage from solar panel.
When battery is full then the circuit stop power from panel.
This stop battery from overcharge and damage.
Circuit Working:
Parts List:
| Category | Description | Quantity |
|---|---|---|
| Resistors | R1 330Ω set to 14.9V 1/4 watt | 1 |
| R2 330Ω set to 11.9V 1/4 watt | 1 | |
| 470Ω 1/4 watt | 2 | |
| Potentiometer 10k | 2 | |
| Semiconductors | IC1 555 | 1 |
| IC2 7805 | 1 | |
| Transistor BD139 | 1 | |
| LEDs Red 5mm 20mA (charging indicator) | 1 | |
| White 5mm 20mA (general indicator) | 1 | |
| Green 5mm 20mA (dumping indicator) | 1 | |
| Switches Push button (for dumping) | 1 | |
| Push button (for charging) | 1 | |
| Diode 1N4004 | 1 | |
| 12V relay (40 amp) | 1 | |
| Solar panel (16V 60W) | 1 | |
| 12V battery | 1 |
If our solar panel charge battery in less than 10 hours then only we need to dump extra current.
When battery is full then solar power goes to load and uses big resistor or 12V 100W bulb as load.
If battery takes 14 hours or more to charge that is like two days sun.
Then battery charge slow with no damage which might not be in this circuit.
To charge without circuit connect high watt resistor and diode in line with solar panel and battery.
Battery charge slow over few days.
Use variable power supply instead of fixed panel.
No need for high power resistor, battery, panel or relay.
Set power supply to 11.9V.
Turn top 10k pot to light charging LED.
Then set voltage to 14.9V.
Turn bottom 10k pot to light dumping LED.
Before use connect all parts like circuit says and check voltage is right.
IC1 555 does not work well under 5V so white LED lift 7805 IC2 output to 8.5V.
Press any button quickly to start charge or dump.
IC1 555 change state to do charge or dump.
If we do not have variable power source then put small 12V battery in circuit it will charge fast and we can see voltage change.
Watch how it goes between low 11.9V and high 14.9V.
Adjust voltage set points each time it cycle.
This test is easy but just wait battery to reach 11.9V and 14.9V.
Use old junk battery for test.
How To Build:
To build a IC 555 Solar Charger Controller Circuit follow the below mentioned steps for connections:
- Put all parts same like in circuit diagram.
- Pin 1 of IC 555 goes to ground.
- Pin 2 of IC 555 connect to push button 1 to ground and also connect R1 resistor from pin 2 to middle leg of P1 potentiometer.
- Pin 3 of IC 555 connect to 12V battery (+) through red charging LED and resistor R3.
- Also from pin 3 connect resistor R4 to base of transistor T1.
- Pin 4 of IC 555 connect to 12V battery (+).
- Pin 6 of IC 555 connect through resistor R2 to center leg of pot P2.
- Pin 8 of IC 555 also connect to 12V battery (+).
- IC2 7805 input pin goes to 12V battery (+).
- IC2 ground pin goes to battery negative (–).
- IC2 output pin goes to pin 4 and pin 8 of IC 555 and also give power to rest of 555 circuit.
- Transistor T1 emitter goes to ground.
- Collector goes to one side of relay coil.
- Other side of relay coil goes to 12V battery (+).
- Base of transistor T1 connect through green dumping LED and resistor R4 to pin 3 of IC 555.
Solar panel of 16V Connection:
- Positive wire goes to relay common terminal.
- Negative wire goes to ground.
- Dump push button (button 1): pin 2 of IC 555 to ground.
- Charge push button (button 2): pin 6 of IC 555 to output pin of IC2 7805.
Safety Tips:
- Better to use ready made solar charge controller.
- It has safety inside and is good for expensive battery and panel.
Conclusion:
This IC 555 Solar Charger Controller Circuit helps battery charge the proper way.
It stop too much charge, protect battery and use power from solar panel slowly and safely.