Future Planning for Charging Cycle : The bulk charge begins when the solar panel voltage is larger than the battery voltage. When the battery voltage reaches 14.4V, absorption charge will be entered. The charging current will be regulated by the PWM signal to maintain the battery voltage at 14.4V for one hour.
The Charge Cycle consists of 3 stages. Stage 1 Bulk charge: Arduino will connect the Solar Panel to the battery directly ( 99 % duty cycle). The battery voltage will increase gradually. When the battery voltage reaches 14.4V, stage 2 will begin. In this stage, the current is almost constant. Stage 2 Absorption charge:
The bulk charge begins when the solar panel voltage is larger than the battery voltage. When the battery voltage reaches 14.4V, absorption charge will be entered. The charging current will be regulated by the PWM signal to maintain the battery voltage at 14.4V for one hour. Float charge will then enter after one hour.
The amount of charging current is determined by the difference between battery voltage and charge setpoint voltages. The controller uses two stages charging algorithm. According to the charging algorithm, it gives a fixed frequency PWM signal to the solar panel side p-MOSFET.
Load Control If you are planning to install an off-grid solar system with a battery bank, you’ll need a Solar Charge Controller. It is a device that is placed between the Solar Panel and the Battery Bank to control the amount of electric energy produced by Solar panels going into the batteries.
Download the Schematic : Schematic_Arduino+Solar+Charge+Controller+V2.0_Sheet_1_20200320104815 The heart of the Arduino solar charge controller is an Arduino Nano board. The Arduino senses the solar panel and battery voltages by using two voltage divider circuits.