Your inputs
Editable example valuesYour estimate
Live calculationNo location or tariff is detected automatically. All results use the values you enter.
What is this tool used for?
Use this tool to estimate whether adding a battery saves money by storing surplus solar for later use instead of exporting it to the grid.
How to use this calculator
Enter installed battery cost, daily surplus sent into storage, round-trip efficiency, avoided import price, lost export credit, operating days, extra maintenance and assumed service life.
Understanding your results
Savings subtract the export income you give up and account for storage losses. Simple payback exists only when annual net savings are positive. Compare it with assumed service life; the calculation does not put a monetary value on outage protection or model future degradation.
How this is calculated
Before you use the result
Daily stored input must fit battery capacity, charging limits and real surplus. All delivered energy is assumed to displace imports. Constant tariffs and performance; no financing, degradation, replacement or discounting. Backup reliability value is excluded. Negative savings mean storage loses money under these assumptions.
What should I check before using this estimate?
Daily stored input must fit battery capacity, charging limits and real surplus. All delivered energy is assumed to displace imports. Constant tariffs and performance; no financing, degradation, replacement or discounting. Backup reliability value is excluded. Negative savings mean storage loses money under these assumptions.