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Battery sizing: how big should your home battery really be?
Most homeowners over- or undersize their first battery. Here is a five-minute model that gets it right.
Sinova Energy1 min read
Start with the bill, not the brochure
Most installers will quote you a 10 kWh battery as their default. That works for some homes, but for many it is either too small to cover evening loads, or too large to fully cycle each day.
The five-minute sizing model
- Pull your last 12 months of bills
- Average your daily use (kWh per day)
- Subtract solar self-consumption
- Multiply the remainder by 0.6 - 0.8 (battery depth-of-discharge)
- Round to the nearest battery module size
Worked example
A Sydney home using ~20 kWh / day with 6.6 kW solar typically lands on a 10-13.5 kWh battery as the optimum.
Want us to model your home? Use our free quote tool.