What is this article about?

Some Smappee charging points can automatically switch between single-phase and three-phase charging whilst charging. This is useful for solar charging: when there is little sunshine, the car charges in single-phase mode (which is possible from around 1.4 kW); when there is plenty of sunshine, it switches to three-phase mode so that more surplus energy can be utilised. This automatic switching only works in charging modes that prioritise surplus solar energy. It does not occur during normal or scheduled charging.

The following chargers are capable of dynamic phase switching:

Requirements for Dynamic Phase switching

The following products support dynamic phase switching in surplus only

EV Wall Home (V3) (manuals) (wiring)

• (6220xxxxxx) (Cable version)

• (6221xxxxxx) (Socket version)

EV Wall Quantum version (manuals) (wiring)

• (6230xxxxxx) (Cable version)

• (6231xxxxxx) (Socket version)

EV One Latest version (manuals) (wiring)

• (6531xxxxxx) (Socket version)

EV One Business (V3) (manuals) (wiring)

• (6522xxxxxx) (Socket version)

EV One Home (V3) (manuals) (wiring)

• (6521xxxxxx) (Socket version)

Keep in mind

• This is only available if you have a three-phase – star (3 x 400 V) charging station installation. This is not available for any other electrical network such as three-phase – delta (3 x 230 V) or any foreign networks.
  • Having doubts? Please refer to your installer who will be able to determine if your installation is compatible.
• This function is only available during surplus charging:
  • The Solar only mode
  • The Schedules and surplus as part of the Smart charging mode 

Chargers not capable of phase switching

EV Base

EV Dual

Requirements for dynamic phase switching

All the points listed below must be correct, otherwise the dynamic phase switching will not happen:

• It is a supported model (identified by the serial number; our product list provides confirmation).
• The installation is a 3-phase star connection (400 V with neutral). It cannot be used on a delta connection or a single-phase connection.
• The customer has an active licence for smart charging (or, historically, this was included prior to the licence era).

If you don’t notice this behaviour in a charge point, check these points first before looking any further.
 

When will the charger switch to 3 phases?

The charging point (or infinity) monitors the surplus solar energy that would otherwise be fed into the grid at that moment, and which is specifically available for this car. If several cars are charging at the same time, the surplus is distributed fairly and only the car’s own share is taken into account. 

The system only switches to three-phase charging if that surplus exceeds the maximum amount the car can already draw on a single-phase connection. In practical terms:

• With a 32 A charging point: from around 7.4 kW of surplus power.
• With a 16 A charging point: from around 4,2kW of surplus power

The reasoning behind this: as long as a single-phase system can still handle the surplus, switching over is pointless. Only when there is more solar power than a single-phase system can handle does three-phase become useful. The switch must also remain practical: three-phase charging cannot be slower than approximately 4.2 kW, so below that threshold, single-phase is always the better choice.

When will the charger switch back to 1 phase?

As soon as the available surplus falls below that same limit – for example, if a cloud passes in front of the sun or the washing machine starts up – there is no separate, lower limit for downshifting: it is the same threshold in both directions.

The big question: why does it not happen immediately?

Two built-in delay times prevent the charger from constantly switching back and forth in changeable weather:

• The new conditions must persist for at least 1.5 minutes without interruption. A brief cloud or a short spike in intensity therefore makes no difference.
• After a switch, there is a gap of at least 15 minutes between two switching events. Even if the sun’s position changes significantly during that time, the pole remains where it is.

This is by design: the switch in the charging point and the car’s on-board charger will last longer if they are not switched on and off unnecessarily. A customer who says, ‘The sun was shining brightly, but it kept charging in single-phase mode’, is therefore usually simply experiencing this delay, or the surplus was just too small.

Common questions and answers:

• 'It never switches to three-phase.’ 
  • Check the conditions above. If everything is correct, check whether the surplus was large enough (7.4 kW at 32 A).
• ‘It responds slowly to the sun.’ 
  • That’s the 1.5-minute delay plus the 15 minutes between switching cycles. It works as intended. ‘It charges in single-phase, whereas my car can handle three-phase.’ With solar charging, that’s often the right choice: single-phase charging can operate at much lower levels and makes better use of small surpluses.
• ‘It doesn't work with normal charging.’ 
  • That's right; the automatic switch-over is only for surplus solar charging.