Off-Grid Load Sizing Calculator

Summary

Add your appliances, set sun-hours and voltage, and get total daily watt-hours, required battery bank, and minimum solar array size.

How it works

1. Add each appliance by entering its name, wattage, and daily hours of use.
2. The tool multiplies watts by hours to get watt-hours (Wh) per day for each appliance.
3. All appliance Wh values are summed to give total daily energy demand.
4. Enter peak sun-hours for your location and system voltage (12V, 24V, or 48V).
5. Battery bank size is calculated from total daily Wh divided by depth of discharge, converted to Ah at your voltage.
6. Minimum PV array size is calculated as total daily Wh divided by peak sun-hours, with a system efficiency factor applied.

Use cases

• Plan a cabin or tiny house off-grid solar system from scratch.
• Verify whether a proposed solar and battery setup covers your real appliance loads.
• Compare system costs at different voltages (12V vs 24V vs 48V).
• Identify the biggest energy consumers in a proposed off-grid load list.
• Size a solar-powered workshop, remote sensor station, or RV system.
• Teach or learn how solar system sizing calculations work step by step.

Frequently Asked Questions