Off-Grid Solar & Battery Sizing
Enter your daily loads, set peak sun hours and battery type, then get battery bank size, solar array size, and AU rebate estimate.
Daily Load Calculator
List each appliance, its wattage, and how many hours per day you use it.
Preset
Appliance Name
Wattage (W)
Hours/Day
Wh/day
Remove
—
Total Daily Load: 0 Wh/day
System Configuration
5
Use local solar data for your location (typically 3–6).
2–3 days is typical; northern or cloudy locations (e.g. Canada, Alaska) may need more.
Used to calculate how many panels you need.
Battery/system voltage for MPPT sizing.
How it works
- Daily Wh = sum of (watts × hours) for each appliance.
- Battery = daily Wh × days of backup × 1.1 ÷ 0.9 (DoD).
- Battery = daily Wh × 1.1 (efficiency) ÷ 0.9 (DoD).
- Solar = daily Wh × 1.25 (losses) ÷ peak sun hours.
- Inverter continuous = max load; surge = continuous × 2.5 for motors/fridges.
- MPPT amps = (solar W ÷ battery voltage) × 1.25; round up to 20/30/40/50 A.
- Australia: 2026 STC factor 6.8 with tapering (0–14 / 14–28 / 28–50 kWh).