Why your solar panels also shut down

Every inverter connected to the grid has grid disconnection protection. As soon as the inverter notices that the grid voltage has dropped, it switches itself off within a few seconds.

That is not a defect; it is a legal safety requirement. If your installation were to keep working, you would be putting voltage on a grid that technicians are working on at that moment. The protection prevents that.

The result: the sun is shining, your panels are there, and yet you have no power.

A battery alone is not emergency power

This is where expectations often go wrong. A standard home battery also shuts down during a failure, even if it is fully charged. This is because the battery is connected behind the same inverter and therefore behind the same protection.

A battery increases your self-consumption and lowers your bill. That is the core reason to install one. Backup during a power outage is a separate function that you must consciously provide for.

What you actually need

To keep your home running during an outage, three things are needed.

An inverter with a backup output. A hybrid inverter with an EPS output or a system to which a backup module can be added. Brands such as Huawei, SolarEdge, Sigenergy, and AlphaESS offer this possibility, often as a retrofit.

A switch box that disconnects your home. The backup box or system controller detects the failure and physically separates your installation from the grid. Only then can the inverter restart and your battery supply power to your house.

A well-thought-out distribution in your fuse box. In practice, you provide a separate circuit for what really matters: fridge and freezer, lighting, Wi-Fi and modem, the circulation pump of your heating, and a few sockets. Electric cooking, charging a car, and running a heat pump simultaneously is usually not realistic.

Important detail: with a correct backup setup, your solar panels also continue to work during the outage. During the day, your battery simply recharges. This way, you don’t just bridge an hour, but several days in good weather.

In Belgium, a backup setup must be reported to Fluvius and must be carried out in accordance with the AREI. Therefore, always have this installed and inspected by a certified installer.

The bar is higher for companies

For an SME, a farm, or a shop, it’s not about comfort but about continuity. Cooling that fails, a POS system that goes down, gates that can no longer open, a milking robot that stands still.

A battery with a backup function handles short interruptions without anyone having to do anything. For critical processes that cannot tolerate even a second of interruption, an emergency generator or a UPS remains recommended. The combination of both is the most realistic setup for many companies: the battery reduces daily energy costs and covers common failures, while the emergency generator covers the exceptional cases.

Can your installation handle this?

That depends on your inverter, your battery, and your distribution board. Three questions to start with:

• Do you know what type of inverter is on your roof or in your garage and if it has a backup output?
• Do you know if your battery can be expanded with a backup module later?
• Do you know which circuits in your fuse box you really need during an outage?

If you can’t figure it out, we’ll look into it for you. Solar Assistance already monitors more than 10,000 installations today through monitoring, maintenance, and breakdown assistance. We know exactly what you have and what is technically possible, without you having to request a quote first.

In summary

Solar panels always shut down during a power outage; this is regulated by law. A standard home battery does too. Only an installation with a real backup function keeps your home or business running. So know in advance what your system can do, because an outage is a bad time to find out.