“Do I need to provide a battery for each phase?” That question quickly arises when you are connected to a three-phase connection. This is not necessary for normal use while the electricity grid is available. We first look at what consumption you want to absorb and how much power is required for this.
This guide is about homes with a Flemish digital meter and our single-phase battery solutions. Both the addition by the meter and the control of the total grid power play a role. We assess separately what works during a power outage.
For a Brussels installation, we check the Sibelga connection, the available meter type and the permitted battery configuration separately. A reference to Fluvius does not in itself prove how a Brussels meter registers or what structure is permitted there.
Your digital meter looks at the whole thing.
Fluvius confirms that the digital meter adds simultaneous draw and injection across the phases before registering energy. At the same time, only the withdrawal count or the injection count increases. Battery discharge on one phase can thus reduce the recorded consumption on another phase.
That applies at the same time. A surplus from this afternoon will not automatically be offset against consumption this evening. To use that energy later, your battery must actually store it and release it again.
| Part | Power at that moment |
|---|---|
| Battery on phase 1 | Delivers 1,0 kW |
| Device on phase 2 | Requests 1,5 kW |
| Phase 3 | No collection or injection |
| Total to the digital meter | Approximately 0,5 kW consumption |
The load per phase remains important.
The addition by the meter does not physically distribute the battery power over your entire installation. Cables, connections and protection continue to have their own limits per circuit and phase. A low total grid consumption therefore does not prove that each phase is under low load.
That is why we also look at the distribution of solar panels, batteries and major consumers. Fluvius recommends good power distribution for single-phase inverters and refers you to an installer for this. A charging station still requires a regulation that monitors the available power on the relevant phases.
Choose sufficient power and the correct measurement.
Suppose your home together requires 3 kW and the battery can output a maximum of 2 kW at that moment. In a simplified calculation, approximately 1 kW of grid consumption remains. Additional battery modules can store more energy, but only increase delivery power if the system also supports that expansion.
Our battery control uses the total measured grid power. It therefore looks at the joint consumption or injection of the home, not just at the phase to which the battery is connected. We check the entire measuring solution, the measuring direction and the settings, so that the control responds to the correct data.
A three-phase system or a multi-device setup may be appropriate when more power or a different distribution is required. We assess this on your measurements and the permitted configuration, not just on the number of phases of your connection.
Check the supply network type and the selected model.
With a suitable single-phase battery we provide a suitable 230 V connection. On 3 × 230 V it can be created between two phases; on 3 × 400 V + N between a phase and the neutral conductor. The manufacturer's conditions for the specific model, measurement and electrical protection must correspond to that version.
The type of digital meter also does not prove how your home is connected. Fluvius also installs three-phase meters at single-phase connections. We therefore base the choice on the actual connection and electrical installation.
The panel power in kWp also does not prove the grid type. More than 5 kWp solar panels can be combined with a smaller AC inverter. The inverters and the actual connection count for the permitted powers. Two Mix devices together add 8 kW inverter power; that requires a different assessment than one appliance of 4 kW.
Emergency power requires a separate assessment.
The previous examples apply while the grid is present. In the event of a power failure, you cannot count on the same operation via the public grid. Any separate emergency power output only supplies the intended devices within its own boundaries.
If you want to continue using fixed residential circuits, we will design a suitable solution with safe switching. A single-phase emergency power output does not automatically provide a three-phase power supply for, for example, a three-phase heat pump. We determine in advance what must continue to work during a breakdown.
This is how we prepare the choice.
Send us the details of your connection and existing inverter, photos of your meter and closed fuse box and preferably your 15-minute readings. Also mention your charging station, heat pump and any wish for emergency power.
- We check your actual supply network and provide the appropriate connection and electrical protection.
- We compare usable storage capacity and output power with your consumption.
- We look at the distribution over the phases and the complete measurement solution.
- We will agree separately which emergency power function you need.
Short answer
Frequently asked questions
Do I always need three batteries with a three-phase connection?
No. Our single-phase batteries regulate the total measured grid power. This means that one battery can also reduce grid consumption in a three-phase home. The correct size depends on your consumption and the required battery power. More storage capacity does not automatically increase that capacity.
Compare capacity and powerDoes battery discharge count if my device uses power at a different phase?
Yes. The Flemish digital meter adds up the simultaneous consumption and injection over the phases before registering it. This reduces the total measured grid consumption. It does not change the physical load on the individual phases and does not allow you to cancel out afternoon solar power with evening consumption.
Can the same battery also be used on 3 × 230 V without a neutral conductor?
A suitable single-phase 230 V battery can also be connected to a 3 × 230 V mains. We check the regulations for the exact model and the electrical installation. A suitable 230 V connection between two phases is made at 3 × 230 V; on 3 × 400 V + N between a phase and the neutral conductor. The measurement of the total network power remains a different subject than the permitted connection of a specific device.
Does this also give me emergency power on all three phases?
No, that does not follow from the addition by the digital meter. During a power outage, the emergency power supply determines which appliances or circuits are powered. A separate emergency power output is not a three-phase power supply for your entire home. To do this, we assess the suitable equipment, switchover and complete installation separately.
Read what emergency power can powerSources