Battery Energy Savings Calculator
Estimate how many kWh of grid electricity your home battery will save each year, based on your solar generation, consumption pattern and battery capacity.
e.g. Powerwall 3 = 13.5 kWh, BYD HVM = 16.6 kWh
Tesla: 89% · Sungrow/BYD: 96–97%
From your inverter monitoring — daytime energy not used at home
Electricity used from grid after sunset — check your bill or meter
Days with enough solar to charge the battery (est. 280–320 in most AU cities)
Your Results
Usable energy per charge cycle
12.8 kWh
after round-trip efficiency losses
Annual grid energy avoided
3,840 kWh
replaced with stored solar
Battery covers nightly demand
—%
Solar captured annually
— kWh
Est. full charge cycles / yr
—
Calculator notes
- Battery can only store up to its capacity per day — excess solar still exports to grid.
- Battery can only discharge up to the night-time demand — excess charge carries over (or is lost if next day is also full).
- Round-trip efficiency applies to both charge and discharge, so 95% means you recover 95 kWh for every 100 kWh stored.
- Results are estimates. Actual savings depend on your solar system size, household load profile, and seasonal variation.