BatteryPayback
Home battery scenario calculator

YOUR QUOTE · YOUR ASSUMPTIONS

What would your battery need to deliver?

Explore the additional cost of a battery for an existing solar system, compared with the same home and solar system without a battery.

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Battery payback calculator

Your own inputs

Your assumptions

All money inputs must use one currency and the same tax basis for you. No taxes or subsidies are inferred.

Costs and prices

Changing the currency code changes labels only. It does not convert amounts.

Battery, additional inverter, installation, commissioning and mandatory upfront costs, including the taxes you pay. Exclude the existing solar system. Use a decimal point. Do not enter thousands separators or units.

Only charges avoided for each kWh not bought. Exclude unchanged fixed charges. Use a decimal point. Do not enter thousands separators or units.

Net income forgone for each kWh of solar electricity used for charging instead of export. Use a decimal point. Do not enter thousands separators or units.

Include maintenance, subscriptions or separately estimated idle consumption costs. Do not count losses already included in AC efficiency again. Use a decimal point. Do not enter thousands separators or units.

Explain the amount, or use the explicit zero-cost confirmation below when the amount is zero.

Operating and time assumptions

Whole-system AC boundary: energy delivered to the home divided by solar energy that would otherwise be exported. Include charging, discharge, wiring and allocated auxiliary losses. Cell-only DC efficiency is not suitable. 90 means 90%; 0.9 means 0.9%. Use a decimal point. Do not enter thousands separators or units.

Your assumption about declining annual delivery, not a prediction of cell condition. Use a decimal point. Do not enter thousands separators or units.

Use a decimal point. Do not enter thousands separators or units.

Assumed operating life is separate from the warranty. Use a decimal point. Do not enter thousands separators or units.

A real return target, consistent with prices in today’s purchasing power. Use a decimal point. Do not enter thousands separators or units.

Your three usage scenarios

Annual energy delivered to your home is a scenario assumption, not a forecast. Annual consumption, solar generation and battery capacity do not establish when charging and discharge are possible.

Enter first-year AC energy delivered to the home. Equal values are allowed. Lower and Higher describe energy, not which financial outcome is better.

Use a decimal point. Do not enter thousands separators or units.

Use a decimal point. Do not enter thousands separators or units.

Use a decimal point. Do not enter thousands separators or units.

Optional information: Warranty period: Unknown; Solar surplus exported without a battery: Unknown; Grid electricity imported without a battery: Unknown; Usable battery capacity: Unknown; Nominal battery capacity: Unknown.

Optional physical information and warranty
Warranty period
Solar surplus exported without a battery
Grid electricity imported without a battery
Usable battery capacity
Nominal battery capacity

Scenario results

These scenarios are not a confidence interval or a purchase recommendation. Check the quote, operating assumptions and warranty separately.

Enter your assumptions and calculate to see results.

Start with your own assumptions

Enter your quote and three usage amounts, then select Calculate scenarios. No financial defaults have been chosen for you.

What this model leaves to you

Prices and annual costs stay constant in today’s purchasing power. Solar energy that would otherwise be exported is shifted to home use. Annual energy limits do not establish when charging and discharge can happen. Actual ageing, operating life and warranty conditions need separate checks.

No hourly tariffs, grid charging, reserve revenue, loans, automatic subsidies or taxes, backup-power value, replacement battery, residual value or separate end-of-life cost are included. A known mandatory replacement or material end cost does not fit this model. Include mandatory upfront costs in the quote and ongoing additional costs in the annual amount. Unaccounted losses are not assumed covered.

Inputs stay in this page’s memory. They are not sent, logged or stored. Reloading starts with an empty calculator.