Prepare · Power
Backup power
Estimate battery runtime for essential devices. Results are estimates only.
Battery
Appliances
Quick add (wattages are illustrative — check your device label):
No appliances added.
Estimated runtime
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Add appliances with a wattage to see an estimate.
- Total load
- 0 W
- Usable battery energy
- 800 Wh
- Delivered after inverter losses
- 680 Wh
Formula: usable Wh × inverter efficiency ÷ total load W. Real runtime is usually shorter: fridges and freezers cycle on and off, batteries lose capacity in cold weather and with age, and motors draw extra power when starting.
Safety — read before using backup power
- Generators outdoors only, well away from doors, windows and vents. Never in a house, garage, shed or carport.
- Carbon monoxide kills. It has no smell or colour. If anyone feels dizzy, sick or confused, get to fresh air and call 111.
- Never backfeed — don't connect a generator to your home wiring or switchboard. Only a licensed electrician can install a proper changeover switch. Backfeeding can kill line workers and neighbours.
- Never use BBQs, gas heaters designed for outdoors, or charcoal indoors.
- Charge and store batteries as the manufacturer instructs, away from anything flammable. Stop using swollen, damaged or hot batteries.