Solar guide
Solar battery calculator
Estimate whether a solar battery could increase self-consumption and add enough savings to justify its cost.
A battery can store excess solar electricity for later use. This can reduce exports and increase self-consumption, but the extra savings must be compared with the battery cost and lifetime.
Battery savings estimate
Compare annual savings before and after a battery self-consumption uplift.
Estimated battery value
This checks battery value only, not full solar-system ROI.
Open full calculatorExtra value = benefit with battery - benefit without batteryWhen does a solar battery make sense?
A battery is more likely to help financially when export tariffs are low, retail electricity prices are high, and a large amount of solar generation would otherwise be exported. It can also be valuable where backup power matters, although backup value is not included in a simple savings calculation.
High evening usage, low export tariff, high electricity price and enough solar surplus to charge the battery.
Low solar surplus, high battery cost, generous export tariff or very low evening usage.
Backup power and energy independence can matter even when simple payback is slower.
Battery assumptions to check
- Battery installed cost.
- Usable battery capacity, not just nominal capacity.
- Round-trip efficiency losses.
- Warranty and expected battery lifetime.
- Export tariff compared with retail electricity price.
- Whether backup power is included or requires extra hardware.
Solar battery FAQ
Does a battery always save money?
No. A battery must create enough extra savings to recover its cost during its useful life.
Why does export tariff matter?
If export payments are low, storing surplus solar for later use may be more valuable than selling it to the grid.
What is self-consumption?
It is the percentage of solar electricity used directly in the home instead of exported.
Should battery payback be separate from solar payback?
Yes. The battery is an additional investment and should be checked separately as well as inside the full system return.