Path-Q Solar
How much backup energy do I need for overnight outages?
Answer
Estimate the energy used by the circuits you want to run during the outage window, then add a reserve for battery losses, operating limits, and uncertainty. For an overnight outage, focus on essential loads rather than total household consumption unless whole-home backup is intended.
Key points
- List each essential appliance, its typical wattage, and hours of operation.
- Include refrigerators, medical equipment, communications, lighting, heating or cooling controls, and pumps as relevant.
- Separate energy capacity in kWh from power capacity in kW; both must be adequate.
- Use conservative assumptions for cold weather, motor starts, and longer-than-expected outages.
What it depends on
- Essential-load energy consumption
- Outage duration and weather
- Battery usable capacity and efficiency
- Inverter continuous and surge output
Risks and trade-offs
- Oversizing raises cost, while undersizing can leave essential equipment unavailable before morning.
- High startup or simultaneous demand may exceed the inverter's power output, while battery depletion depends on the total energy consumed over time.
Information you may need
- List of essential circuits and appliances
- Typical wattage or interval usage
- Expected outage duration
- Battery usable capacity, efficiency, and power rating
Your next step
What to do next
Create an overnight load worksheet and ask the installer to show the expected state of charge at morning under normal and conservative scenarios.
Path-Q
Find the right next step
Answer a few questions and we’ll narrow your options.
Loading…
SQ00602