How long will a battery last overnight?
See how far into the night a battery runs your home after the sun goes down, in summer and winter, and what size would cover the whole night.
A 13.5 kWh battery on a winter night
All night
Covers sunset (about 5:00pm) to sunrise (about 7:00am), with 1 kWh to spare.
Night-time use11.8 kWh
Battery covers100%
From the grid0 kWh
Size for all night12.5 kWh
Every season
| Season | Night use | Lasts until | Covers |
|---|---|---|---|
| Summer | 6.5 kWh | Sunrise | 100% |
| Autumn | 9.2 kWh | Sunrise | 100% |
| Winter | 11.8 kWh | Sunrise | 100% |
| Spring | 6.8 kWh | Sunrise | 100% |
To get through the longest night of the year, you'd need about 12.5 kWh of usable capacity.
Want to know which size pays off, and what it costs after the rebate?
Plan my systemHow it's worked out
- Your daily use is spread across the day with a typical household pattern: a morning peak, an evening peak from about 5pm to 9pm, and a low overnight base. Use is higher in winter and summer.
- The night runs from an approximate sunset to sunrise for each season in mainland capitals. Darwin's nights barely change through the year; Hobart's summer nights are shorter.
- About 5% is lost getting energy out of the battery. Any reserve you set is never used.
- If you add your solar, we check whether an average day's surplus, after running the home, fills the battery by sunset. Cloudy days fill it less.
What it doesn't show
- Power, not just energy. A battery can only supply so many kilowatts at once, often 5 kW. Ducted air-conditioning, an oven and a kettle together can exceed that, and the grid tops up the difference.
- Blackouts. Not every battery backs up the whole home. Many power only selected circuits, and some need an extra backup box.
- Your actual pattern. Your retailer or smart meter app shows your real hourly use. Heating, cooling and pool pumps at night change the answer a lot.