Plan home backup power by listing essential devices, daily runtime, and target outage hours.
Essential devices
Required capacity
1,215 W total · 2× 100Ah 12V batteries · 20% buffer
| Total load | 1,215W |
|---|---|
| Estimated total surge | 4,500W |
| Required capacity | 1,334Wh |
| Battery bank | 2× 100Ah 12V batteries |
| Inverter efficiency | 92% |
| Avg hourly use | 139Wh/hr |
| Daily energy | 3,335Wh/day |
High surge load detected. Check if your inverter can handle this peak: Inverter Peak Load Surge
Note: Required Wh = average hourly consumption × backup target hours × 1.2 safety factor. Estimated surge uses running watts × 5 for high-surge devices. Battery count assumes 12 V 100 Ah cells at 80% depth of discharge and 92% inverter efficiency.
During an outage, size for circuits you truly need—fridge, lights, internet, and a few outlets—not every HVAC zone or dryer. This tool turns that appliance list into Wh capacity and a starter battery count.
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