Solar Charge Controller Calculator — Free Online Calculator
Size your solar charge controller. Calculate the amps rating needed for your solar panel array and battery bank.
How to Use This Calculator
Enter total solar panel wattage, panel Vmp, battery voltage, and controller type.
The Formula Explained
MPPT: Amps = (Panel Watts × 1.25) / Battery Voltage. PWM: Amps = (Panel Watts × 1.25) / Panel Vmp. The 1.25 safety factor accounts for conditions exceeding STC ratings.