Design the solar array, inverter and battery as one energy system.
Solar panels create energy; the battery changes when that energy is used. A good design balances annual generation, daytime demand, storage capacity, inverter power, tariff control and export opportunities.
Do not compare systems on battery capacity alone.
Solar array size
kWp describes the panel array’s rated peak output under standard test conditions—not guaranteed real-time generation.
Battery capacity
kWh describes stored energy. Usable capacity is lower than or different from nominal capacity depending on the product and settings.
Inverter output
kW limits how much power can be supplied or converted at once, subject to model and operating mode.
Household demand
Appliance timing determines whether energy is used directly, stored, imported or exported.
Match the battery to the gap between generation and demand.
The useful storage requirement is often the energy needed from late afternoon until the next low-cost charging or solar period.
Illustrative examples
- 5 kWh may cover lighting, refrigeration, electronics and modest evening cooking in some homes
- 10 kWh can cover a broader evening/overnight profile but may still be small beside electric heating
- A 3.6 kW inverter cannot deliver 7 kW just because the battery contains 10 kWh
- Oversizing storage can leave capacity unused; undersizing can create avoidable peak imports
Figures are simple energy illustrations, not guaranteed runtime. Allow for battery reserve, conversion losses, temperature, ageing and changing household demand.
Use solar directly first, then decide what surplus should do.
- Solar serves live household demand where available
- Suitable surplus can charge the battery
- Further surplus may be exported
- The battery supports demand later within its power limits
- The grid supplies any shortfall
- Smart schedules may charge from the grid at selected times
Export still has value
A battery should not be programmed to avoid export at any cost. On some tariffs, exporting solar can be more valuable than storing it, while off-peak grid charging may be cheaper.
The best strategy depends on current tariff terms and household behaviour.
Profile, model, specify and optimise.
Profile
When electricity is used and what may change.
Model
Seasonal solar, storage and tariff scenarios.
Specify
Panels, inverter, battery, meters and backup options.
Optimise
Monitoring, schedules and export settings after handover.
Planning solar and battery storage together?
Let us compare generation, usage and storage as a complete system rather than selling an arbitrary package.