A solar charge controller regulates the voltage and current coming from your solar panels which is placed between a solar panel and a battery.It is used to maintain the proper charging voltage on the batteries. As the input voltage from the solar panel rises, the charge controller regulates the charge to the batteries preventing any overcharging.
Advantages of PWM charge controller:
- Higher charging efficiency
- Longer battery life
- Reduce battery overheating
- Minimizes stress on the battery
- Ability to desolate a battery.
This charge controller can be used for:
- Charging the batteries used in the solar home system
- Solar lantern in the rural area
- Cell phone charging
How our system Works
At first, the charge controller will check the solar panel voltage and compare it with battery voltage, If it is greater than the controller will start sending pulse width modulation (PWM) signals to the MOSFET (Q1) in order to charge the battery.When the solar panel voltage was below the battery voltage, this PWM signals will not send by Controller.
Then next the microcontroller will check the battery voltage, if the battery voltage was below 13.2 volts then the battery will be charged in boost mode, that means the battery will be charged with maximum amperage, this boost mode of charging will be done by sending pulse width modulation signals with 95% duty cycle.
When the battery voltage reaches13.2V the charging mode will turn as absorption mode from boost mode, this was done by changing the duty cycle from 95 % to 10%.This absorption mode will keep the battery fully charged.
A pulse will be sent to the load MOSFET (Q3) to enable the load during the night, if the battery was too low and reaches to 10 volts then in order to prevent deep discharge of the battery, the load will be disconnected.