A home battery does not generate electricity. It moves it — storing energy when it is cheap or plentiful and releasing it when it is expensive or scarce.
This visualiser shows those movements. Adjust solar generation, household demand and battery state to see how electricity flows between the panels, the home, the battery and the grid, and where the surplus or shortfall ends up.
This visualiser has a lot to show at once and works best on a tablet or desktop. On a phone you may need to scroll within it.
The energy paths a battery creates
- Solar to home
- The most valuable path. Electricity used the moment it is generated avoids buying it at the full import price.
- Solar to battery
- Surplus generation stored instead of exported. Limited by the battery's charge power and how full it already is.
- Battery to home
- Stored electricity released when the panels cannot cover demand, typically through the evening peak.
- Grid to battery
- Charging from the grid on a cheap overnight rate. This is how a battery earns its keep in winter, when there is little solar surplus to store.
- Solar to grid
- Export. What happens to surplus once the battery is full or cannot accept charge fast enough.
- Grid to home
- Import. Whatever solar and battery together cannot cover.
Two limits that shape everything
Battery behaviour is governed by two separate figures that are easy to confuse.
Capacity, in kWh, is how much energy the battery holds — how long it can run the home.
Power, in kW, is how fast it can charge or discharge — how much of the home’s demand it can cover at any moment.
A large battery with modest discharge power may still leave you importing during a cooking peak or an EV charging session. A battery with high power but small capacity will cover those peaks but empty quickly. Both figures need checking on a quote.
Round-trip losses also apply: some energy is lost converting electricity in and back out again, so a battery returns less than it takes in.
Reading the model
This is a simplified illustration of how the flows relate to one another, not a performance forecast. Real behaviour depends on your tariff, the inverter's control strategy, battery reserve settings and your actual half-hourly consumption.
Go deeper on battery storage
- Home Battery kW vs kWh Explained — the capacity and power distinction in full
- Battery Round-Trip Efficiency — how much energy storage actually loses
- What Size Home Battery Do I Need? — matching capacity to what you want to shift
- Solar, Battery and EV Working Together — charging priorities and control conflicts
- Smart Energy Tariffs Explained — how cheap overnight rates change battery economics
Work out the right battery for your home
Capacity, power and tariff all matter. Size the battery around the electricity you actually want to shift.