Home batteries, how do they work?

With home batteries, you can store and use the production surplus of your solar panels at times when your solar panels produce too little energy. That is certainly interesting when you have solar panels that were installed after 2020. Why? You can read that later in the article. First, we tell you how such a battery works and what the advantages and disadvantages are.

What are home batteries?

A home battery stores your produced solar energy so that you can use it when your solar panels do not generate enough energy, such as at night, on a very cloudy day, or at peak times.

In addition, a home battery can store cheaper energy from the electricity grid during off-peak hours for later use. This way, you can also enjoy stored energy at off-peak rates during peak hours. You can read how much you can save using a home battery in the article  How cost-effective is a home battery? It also gives you more information about the defined premiums.

How do home batteries work?

A home battery is actually part of a complete system, usually consisting of solar panels, a battery with an inverter, a battery power meter, and an emergency switch.

A home battery provides the most in combination with solar panels, which convert sunlight into electricity. This electricity can be used immediately in your home if it is converted to an alternating current or is stored in the battery.

Role of the inverter

The inverter is connected on one side to the electrical box and on the other side to the solar panels and the home battery. For example, the inverter can make electricity from the solar panels or the home battery available to the home via the electricity box. Conversely, the inverter can draw power from the grid via the electrical box to store it in the battery.

Solution for power failures

Optionally, you can opt for an emergency power installation. During a blackout, it ensures that the energy stored in the home battery is used to provide electricity for lighting, heating, and important appliances. A home battery is also a quiet and ecological alternative to an electricity generator on fuel oil or petrol.

Do home batteries allow complete independence?

Manufacturers of home batteries sometimes dare to promise that their product enables complete independence from the electricity grid. In reality, however, that is not (yet) the case. From October to March you are still dependent on the electricity grid for your electricity. However, that does not mean that a home battery is not a worthwhile investment. The combination of solar panels and a home battery makes it possible to become about 75% independent of the electricity grid. In comparison: an average solar panel installation without a home battery guarantees you an average of 30% independence.

The benefits of a home battery

  • The temporary overproduction of your solar panels does not flow into the grid, but you can reuse it in your home at a later date.
  • The profitability of your solar panel installation increases. Within that rate, your solar panels will yield the most if you  can increase your  self-consumption as much as possible. A home battery can be an important link in boosting that ‘immediate consumption’.
  • You enjoy lower electricity costs.
  • A home battery also serves as an emergency generator during power cuts.
  • You become much less dependent on the electricity grid.
  • Until 2024, you will receive a premium from the Flemish government for the purchase and installation of a home battery.

The disadvantages of a home battery

  • The prices of home batteries are still fairly high today, starting from 7,342 dollars to 16,316 dollars, depending on the capacity you want.
  • Because of fewer hours of sunshine in winter, you do need (more) energy from the grid.
  • The battery takes up some space.
  • Energy storage also requires energy.
  • Some home batteries contain scarce or harmful substances.


If you understand how it works and weighs up the pros and cons, a home battery in 2021 is already interesting in living situations with high power consumption and many electrical appliances (just think of a heat pump and/or electric car). 

Another article on this blog that may interest you:

Batteries: Composed of 5 materials