PLAN THE POWER THAT MATTERS
What stays on
when the grid goes off?
Choose your essentials and explore the tradeoffs. These are editable planning examples, not a system recommendation.
Choose your essentials.
Example appliance values. Use equipment specifications for an actual design.
YOUR ILLUSTRATIVE SCENARIO
Energy-only estimate at the selected average use, with no solar recharging.
- Average demand
- 0.15 kW
- All selected loads running
- 0.27 kW
- Largest startup + other loads
- 0.98 kW
- Energy after reserve + losses
- 9.72 kWh
Assumptions and limits
Runtime = battery kWh × remaining fraction after reserve × 90% efficiency ÷ average kW. Duty cycles are illustrative averages; real appliances cycle differently. Startup considers one motor starting while other selected loads run, not every simultaneous start. Temperature, age, battery state, surge duration and compatibility are not modeled. Custom load assumes continuous use and no extra startup demand. Do not use this tool for medical-device backup decisions.
What changes with a generator?
A generator depends on fuel supply, equipment ratings, transfer controls and service. Compare the running and startup loads above with a qualified installer; this tool does not size a generator or estimate fuel endurance.
Discuss this backup plan →