Brownout backup planner
See why some appliances are easy to back up and others — like aircon — need a much bigger battery.
Your indicative backup size
- Running load
- 325 W
- Energy for 4 h
- 1 kWh
- Battery (indicative)
- ~1.4 kWh
- Inverter (indicative)
- ~0.7 kW
What uses the battery
- Electric / stand fan40%
- Refrigerator30%
- LED light bulb16%
- Phone / tablet charging8%
- Wi-Fi router & modem6%
Motor loads (fridge, pump, washer, aircon) draw extra power when they start, so the inverter is sized with more headroom.
Assumes 80% of battery capacity is usable and 90% conversion efficiency. This is a teaching estimate, not a system design — battery and inverter models, and what circuits can be backed up, are confirmed after inspection.
Ask us to size this for my home