Off-grid with 25 kWh GREENROCK for a family in Belgium

Living off-grid and self sustainable with an island mode storage system. That’s what the owner of a family home in Belgium wants to establish. The family owns a hybrid car and has all electric appliances (no gas connection). The family with two children and a cat are getting there step by step. They provide for their own water with a triple filter system and produce their own energy.

In total there are 16 kWp photovoltaic panels on the roof of the house. In several installation steps, the system grew to this size. With installation of the 25 kWh GREENROCK batteries 2,5 kWp of photovoltaic were added and DC coupled. Now the system is an off-grid system and works in island mode.


We distinguish between emergency power supply and island operation or off-grid. Below we explain the differences. Depending on how far the customer wants to protect himself from possible power failures, we recommend different system designs. Each GREENROCK system is designed for emergency back-up. For island operation or off-grid, we offer the DC coupling for the PV system.

What is emergency power supply?

Together with the electrician, the main consumers in a house are defined. These run on their own emergency circuit. In the event of a power failure, the battery supplies these devices with power. For example Alarm system, refrigerator, lighting, … are supplied. Emergency power supply is providing power until the batteries are completely discharged. If you have a photovoltaic system, it will only start producing power as soon as the grid is back to work. With an emergency power function of your battery system you can cover power outages of a few hours.

What is an island system or off-grid installation?


A complete protection during a power failure is possible with a so called off-grid or island system. The difference to the emergency back-up supply is that the photovoltaic is DC coupled. As a result, the photovoltaic provides energy even during a power outage. The batteries can be recharged and allow a long lasting power supply. If the batteries are completely discharged, energy is needed to restart the system. This is called a black start. Even without the energy from the grid, the system can start up again with the energy from the photovoltaic system. Here, too, the electrical engineer determines with you which consumers are to be supplied in the off-grid cycle. Due to the high consumption, an electric stove is usually not included in this cycle.

Back to the installation in Belgium

Now the family has supplemented their energy concept with a 25 kWh GREENROCK Home Saltwater battery system. In addition to the aspects of having a safe and environmentally friendly storage the family is convinced by the fact that saltwater batteries can be discharged by 100%.




The energy management system which is included in every GREENROCK Home system added up to the advantages of GREENROCK. A charging station for the e-car easily connects to the battery system. The energy management system shifts loads and handles heating systems as well as the e-car charging station.

In a next step the family wants to install a wind turbine. The additional power will add up power especially when there is no sun shining.