Home Battery Payback Calculator

Payback periods vary widely. Grid arbitrage alone typically falls in the 8 to 15 year range. Pairing a battery with solar can bring this down to 6 to 12 years, particularly when solar self-consumption is significantly increased. Battery grants, which are available in many countries, can reduce payback by several years.

It depends on your rate spread. After RTE losses of 5–15%, a peak-to-off-peak spread below 50% often produces a poor financial return over the battery's life. A time-of-use tariff with a large rate gap — charging at night at a low rate and discharging at a high peak rate — is the key factor. Enter your actual rates to see whether arbitrage makes sense for your situation.

In most cases, yes. A battery lets you store excess solar generation and consume it when the sun is not shining, raising self-consumption from a typical 20–40% up to 50–75% or more. The saving comes from avoiding grid imports at your full import rate, rather than exporting at a lower feed-in rate. The improvement in payback depends on solar system size, battery capacity, and local electricity prices.

Grants and incentives vary by country and change regularly. In the US, the Inflation Reduction Act includes a 30% tax credit for battery storage (Section 48). In the UK, battery storage installed alongside solar qualifies for zero-rate VAT. Germany, Ireland, Australia and other countries have their own programs. Always check current eligibility before purchasing — amounts and qualifying criteria change frequently.