Enter the battery's usable kWh. For a lead-acid battery rated in amp-hours, multiply Ah by volts and by the safe depth of discharge.
How it works
Hours = usable kWh × (1 − reserve) ÷ load in kW.
Example: 10.0 kWh running 0.5 kW lasts about 18.0 hours.
At a glance
Same settings as the calculator, changing only the battery.
| Battery | Run time |
|---|---|
| 1 kWh | 1.8 hours |
| 5 kWh | 9.0 hours |
| 10 kWh | 18.0 hours |
| 13.5 kWh | 24.3 hours |
| 27 kWh | 48.6 hours |
| 40.5 kWh | 72.9 hours |
Common questions
How long will a Powerwall last in an outage?
13.5 kWh runs a 1 kW load for 13.5 hours. With solar recharging during the day it can last much longer.
What uses the most battery?
Central air conditioning, electric heat, water heaters, ovens and EV charging. Leaving them off stretches backup time.
Sources
- Tesla, Powerwall 3 specifications: https://service.tesla.com/docs/Public/Energy/Powerwall/Powerwall-3-with-Gateway-3-Installation-Manual-NA-EN/GUID-EC527BC7-4750-4425-BBC4-DB8C000339B3.html