Battery integration

Adding a battery to your solar PV system allows you to store the electricity you generate during the day for use in the evening or on cloudy days. This significantly increases your “self-consumption” and reduces your reliance on the national grid.

Why add a battery?

Without a battery, most households only use about 20% to 30% of the solar energy they generate. The rest is exported back to the grid. With a battery, you can increase this to 70% or more.

  • Maximise savings: Use more of your “free” solar electricity instead of buying expensive power at night.
  • Energy resilience: Some batteries can provide backup power during a grid outage.
  • Time-of-Use optimization: Use smart tariffs to charge your battery from the grid when electricity is cheapest (e.g., at night).

How it works

  1. Generation: Solar panels produce DC electricity.
  2. Conversion: The inverter converts DC to AC for home use.
  3. Storage: Excess electricity is diverted to the battery (converting it back to DC for storage).
  4. Usage: When solar generation is low, the battery sends DC back through the inverter to power your home.

Types of integration

DC-coupled systems

The battery is connected directly to the solar panels before the inverter.

  • Best for: New installations.
  • Pros: More efficient because there are fewer conversion steps (DC to AC to DC).

AC-coupled systems

The battery has its own dedicated inverter and is connected to your home’s AC system.

  • Best for: Retrofitting a battery to an existing solar system.
  • Pros: Independent of your existing solar inverter.

Choosing the right battery size

Battery capacity is measured in kilowatt-hours (kWh). Choosing the right size is a balance between your average daily generation and your evening energy usage. Use our battery sizing calculator to get a personalized recommendation.

  • Small (2kWh - 5kWh): Good for small homes or those with lower evening demand.
  • Medium (5kWh - 10kWh): The most common size for UK family homes.
  • Large (10kWh+): Suitable for large homes or those with electric vehicles or heat pumps.

Important: Not all solar inverters are compatible with all batteries. Always check with your installer to ensure your hardware is fully compatible.

More information

For a deeper dive into battery technology, safety, and costs, see our main Batteries section.