SOLAR GENERATORS
How to Size a Solar Generator for Home Essentials
Calculate the battery, inverter and solar-panel capacity needed for essential household loads during an outage.
Size a solar generator in three steps: calculate daily essential watt-hours, verify simultaneous and starting watts, then estimate realistic daily solar collection. The system must satisfy all three; a large battery with an undersized inverter or inadequate panels will miss the goal.
- ✓ Build a 24-hour energy budget
- ✓ Allow for compressor and pump surge
- ✓ Use realistic sun hours and system losses
Create the daily load table
For each essential appliance, record watts and hours per day. Use measured kWh for refrigerators and freezers. Add 10–25% reserve after accounting for inverter and battery losses.
Size power separately from energy
Add devices likely to run at the same time for continuous output. Check the largest motor-starting event and confirm the inverter’s surge duration, not just a promotional peak number.
- Avoid planning around electric heaters and kettles
- Include inverter standby consumption
- Confirm battery operation at expected temperatures
- Keep critical medical loads on approved backup
Estimate the panel array
Daily solar energy is approximately panel watts multiplied by equivalent full-sun hours and system efficiency. Use conservative local seasonal sun data and respect the unit’s maximum solar voltage, current and input power.
Actual energy use and product performance vary by equipment, conditions and installation. Confirm measurements and manufacturer specifications. Qualified professionals should handle permanent wiring and transfer equipment.