Home battery for solar panels (batería doméstica)

What a solar battery does

A battery stores the energy your panels produce in excess during the day so the house can use it when there is no sun. Instead of exporting the surplus for a credit, you keep it and use it at night, when you would otherwise have to buy energy.

Types and capacities

• Lithium: the technology installed in homes today, for its size, number of cycles and safety (standard UNE-EN 62619).
• Capacity: 5 to 15 kWh in homes, chosen by what you use from sunset to morning.
• Connection: to a hybrid inverter, or with its own battery inverter when added to an existing system.

In 2025, 61 % of new residential installations already included a battery, according to UNEF. As a reference, a 6 kWp system with a 5 kWh battery cost 10,000 to 14,000 euros in 2026.

When it pays off

A battery beats surplus compensation when:

• You use a lot at night (summer air conditioning, aerothermal heat pump, electric car).
• Your surplus is paid at a low price and part of it is lost each month.
• You want backup during power cuts, provided the system can run isolated from the grid.

If almost all your use is during the day or your surplus is small, it may not pay off yet. With a compatible electric car, bidirectional charging (V2H) can use its much larger battery to power the house. See solar panels in Seville, Spain.