Power outages are not something we frequently experience in the Netherlands, but when they occur, the impact can be significant. Especially if you rely on electrical devices such as a heat pump, medical equipment, or simply lighting. A home battery provides an ideal solution as an emergency backup in such cases. But how does it work exactly? A home battery, if equipped with a backup function, can automatically continue powering critical devices when the grid power fails. This ensures that your home continues to function partially, even if the rest of the neighborhood is without power. In this blog, we explain how a home battery works as a backup, what happens during a switch, and what you need to consider to properly prepare your home. This way, you not only operate more sustainably but are also prepared for unexpected situations.

What does a home battery do during a power outage?

When the power goes out, a home battery with a backup function automatically initiates a switchover. This is also known as “seamless switching.” The battery detects the outage and switches to the internal power supply within milliseconds. As a result, important devices, such as your refrigerator, lighting, or internet router, continue to work without any action required on your part. However, it is important to know that a home battery usually cannot supply power to your entire house for an extended period. Therefore, it is wise to choose which devices are essential during an outage. These are often:

• Refrigerator and freezer

• Basic lighting

• Heating (depending on the system)

• Internet and communication equipment

• Basic kitchen appliances such as a kettle or coffee maker

By setting priorities in advance, you can efficiently use the available battery capacity during a power outage.

How does the switch from grid power to the home battery work?

The switch from the power grid to the home battery happens very quickly. A well-installed backup system often switches within 20 milliseconds, which is so fast that your devices barely notice it. There are two types of home batteries: systems that switch automatically and systems that need to be activated manually. For optimal protection, it is best to choose automatic backup systems. These often have an integrated 'backup box' or special backup output on the inverter. During the switch, your home is disconnected from the public grid (to prevent feeding back during a fault) and the home battery independently powers the chosen circuits. Smart home batteries automatically distribute the available energy over the essential devices, allowing you to use the stored energy for as long as possible.

Choosing critical devices: what should you connect?

To make smart use of your home battery as an emergency backup, it is important to determine in advance which devices you want to keep using during a power outage. Think of a selection of critical devices essential for comfort, safety, and communication. Most households choose:

• Refrigerator and freezer (to prevent food spoilage)

• Basic lighting in the kitchen, living room, and hall

• Router and modem for internet connection

• Phones or laptops to stay in touch

• Small heating devices if possible

Keep in mind that large consumers such as electric ovens, washing machines, or full heating systems require too much energy for prolonged backup. By making these choices in advance and installing them on a separate circuit, you can get the most out of your home battery in case of emergency.

How long can you rely on your home battery during a power outage?The duration you can rely on your home battery during a power outage depends entirely on two factors: the storage capacity of your battery and the energy consumption of the connected devices. Suppose you have a battery of 10 kWh and your critical devices together consume about 1 kWh per hour, then you can bridge approximately 10 hours. By using your energy consumption wisely – for instance, by dimming lights or selectively turning on devices – you can extend the available time. Some advanced systems even have a 'load shedding' function where less critical devices are automatically turned off when the battery capacity falls below a certain level. This way, even during longer outages, you can remain operational for as long as possible. For longer periods of outage, it may be advisable to combine with an emergency generator or alternative charging options such as solar panels, provided the system supports it.Why a home battery is becoming increasingly interesting as an emergency solutionWith the increasing risk of grid congestion, weather influences, and the growing use of electrical devices in the home, being prepared for power outages is becoming more important. A home battery not only provides financial benefits by optimally using solar energy and dynamic rates but also gives you extra security and independence. By keeping essential devices running, you significantly increase your living comfort and safety. Additionally, with a good energy storage solution, you show that you actively contribute to a more stable and sustainable energy system. Investing in a home battery is therefore not only smart for your wallet but also for the future-proofing of your home.Frequently asked questions about home batteries as emergency power supplyCan every home battery provide emergency power during an outage?
No, only models with an integrated backup function can do this.How quickly does a home battery switch during a power outage?
Within 20 to 50 milliseconds, almost without noticeable interruption.Do I have to connect my entire house to the battery?
No, only critical appliances for maximum efficiency.Can I also generate new power with solar panels during an outage?
Only if your home battery and inverter are suitable for this.How big should my battery be for a good backup?
Depending on your needs; 5-10 kWh is average for basic provisions.Do I lose a lot of energy during the switch?
No, the switch is almost lossless.Is an emergency backup standard with a home battery?
No, you must specifically select this when purchasing.Can I also combine dynamic electricity prices with emergency power?
Yes, many modern systems support both functions.