Solar Battery Calculator
Solar Battery & Solar Array Sizing Calculator
Estimate your battery bank size and minimum solar array based on your energy needs.
Application
Appliances
Autonomy
Many appliances do not draw a constant amount of power. For example, a refrigerator cycles its compressor on and off throughout the day, meaning its wattage continuously changes rather than remaining at its rated value. Similarly, air conditioners, furnaces, pumps, and other motor-driven devices have varying power demands and may require significantly higher surge wattage during startup.
This calculator assumes a constant power draw for each appliance and does not account for cycling loads, startup surges, inverter efficiency, battery losses, temperature, battery age, or other real-world factors. For best results, size your battery and inverter with an appropriate safety margin.
How Battery Capacity Is Calculated: This calculator estimates the required battery size based on your daily energy usage, the number of days you wish to operate without charging, your system voltage, and the usable capacity of the selected battery chemistry. Solar array recommendations are calculated using estimated peak sun hours and an overall system efficiency of 75% to account for typical real-world losses.
Important: This calculator provides estimates based on the wattage and runtime you enter. Many appliances—including refrigerators, freezers, air conditioners, furnaces, pumps, and other motor-driven equipment—do not draw a constant amount of power. Instead, they cycle on and off throughout the day, causing their actual energy consumption to vary. This calculator does not account for appliance duty cycles, startup surges, temperature, or other operating conditions. For the most accurate results, use the appliance's measured daily energy consumption (Wh or kWh), if available.
Tip: For refrigerators and freezers, use the appliance's daily kWh rating from the EnergyGuide label or a power meter instead of multiplying the rated wattage by 24 hours.
Your Results
Many appliances do not draw a constant amount of power. For example, a refrigerator cycles its compressor on and off throughout the day, meaning its wattage continuously changes rather than remaining at its rated value. Similarly, air conditioners, furnaces, pumps, and other motor-driven devices have varying power demands and may require significantly higher surge wattage during startup.
This calculator assumes a constant power draw for each appliance and does not account for cycling loads, startup surges, inverter efficiency, battery losses, temperature, battery age, or other real-world factors. For best results, size your battery and inverter with an appropriate safety margin.
How Battery Capacity Is Calculated: This calculator estimates the required battery size based on your daily energy usage, the number of days you wish to operate without charging, your system voltage, and the usable capacity of the selected battery chemistry. Solar array recommendations are calculated using estimated peak sun hours and an overall system efficiency of 75% to account for typical real-world losses.
Important: This calculator provides estimates based on the wattage and runtime you enter. Many appliances—including refrigerators, freezers, air conditioners, furnaces, pumps, and other motor-driven equipment—do not draw a constant amount of power. Instead, they cycle on and off throughout the day, causing their actual energy consumption to vary. This calculator does not account for appliance duty cycles, startup surges, temperature, or other operating conditions. For the most accurate results, use the appliance's measured daily energy consumption (Wh or kWh), if available.
Tip: For refrigerators and freezers, use the appliance's daily kWh rating from the EnergyGuide label or a power meter instead of multiplying the rated wattage by 24 hours.