Zaptec Pro load and phase balancing enables the maximum possible charging capacity for each installation. It provides dynamic phase allocation, rotation, and balancing as well as load limiting.
☝️ This feature is available on all chargers that are registered and connected with the Zaptec Portal.
This video explains how the Zaptec charging solution in theory.
Zaptec's unique phase balancing solutions ensures optimal use of all three powered phases. A lot of electric vehicles charge on only one of the phases, but with our system, the load is automatically distributed to all three phases. When several cars are connected the charging effect changes to provide everyone with power.
If you have limited capacity in your building you can measure your building's power consumption using the Zaptec Sense. The charging system then automatically adapts to the buildings power consumption.
Do you want to see how the load and phase balancing can work between the chargers?
👉 Try out our inCharge demo.
Click on the chargers and watch the system distribute the load to the different phases.
Factors that affect the charging solution
Changes in an installations runtime, e.g. vehicles are connected, current limits change, and so on, will trigger the load balancer to run.
There are many factors that are taken into consideration when resolving the optimal charge configuration for an installation. Such as cloud settings in the Portal, current status, and power management.
- Network type
We support three-phase charging on both 400V TN and 230V IT (Norway) installations. For three-phase IT installations the chargers are set to single-phase charging by default. The installation will balance on all three phases, even if the vehicles only receive single-phase charging. This is bc very few vehicles support 3phase charging on IT.
- Charging system circuit breaker (A)
The maximum total current that can be supplied to the installation. This is normally set to match the rating of the incoming circuit breaker. It is safe to set this value to less than the rating of the incoming circuit. Never set this value to exceed the rating of the incoming circuit. The setting is only available for users with Service permission.
- Circuit breaker (A)
An installation consists of a single charging system circuit breaker and one or more circuits. Circuits are configured via the Zaptec Portal. This setting should usually match the physical circuit's circuit breaker, and will limit the current allocated to chargers in the circuit. Because this setting needs to match the physical constraints of the installation, it is only available for users with Service permission.
- 3 to 1-phase switch current
This setting determines when a vehicle should be switched from three-phase to single-phase charging. The default current is 15A, meaning that if the allocated three-phase charge current drops below 15A, the charger will be assigned to a single-phase instead. For most installations, this configuration will provide the best capability. For installations that have a limited number of charging stations, or a low maximum installation current (<32A), it may be useful to set this current lower to allow more chargers to operate on three phases. If a TN 3-phase installation should only offer single-phase charging, the setting can be set to 32A. The setting can be changed by users with Owner or Service permission.
- Maximum and minimum current
The maximum current a charger can provide. Can be used together with charger max phases to limit how much power the charging station should provide. This setting is available to users with Owner or Service permission on the charger.
The lowest current the charger will accept. The balancing algorithm will not allocate current to the charger if it drops below this threshold. This setting is available to users with Owner or Service permission on the charger.
- Max phases
The maximum number of phases a charger can be allocated (one or three). Can be used together with the charger maximum current to limit how much power the charging station should provide. This setting is available to users with Owner or Service permission on the charger.
- Prioritized current
By setting priority to a charger it will be allocated charge current before other charging stations. This will affect the fairness of the system and can prevent other charging stations from providing efficient charging. If capacity is low, or other charging stations are configured with priority, we cannot guarantee charge current. You can set priority under the chargers Settings in Portal.
- Charger online status, offline current, and phase
If a charger is offline, we do not know whether the charger is active or not. Zaptec Portal automatically optimizes offline current and phase for installations every hour, ensuring that offline chargers can provide as much current as possible without triggering any circuit breakers in case all chargers in the installation are active at the same time. The offline current and phase setting is sent to the charger when it's online. If a charger goes offline, it will provide current according to the offline settings, and the balancing algorithm will reserve offline currents to prevent circuit breakers from triggering.
In addition to these settings, the current status of the installation is also part of the equation.
- Charge queue
Depending on the installation max and available current, and the number of active chargers, there may not be enough power in an installation to start new charge sessions. Sessions will be queued if there is not enough power and will be started as soon as other sessions finish. Queued sessions are started in the order they were connected. If sessions need to be stopped when installation max or available current is decreased, this is also handled by the charge queue. Sessions are started and stopped in a FILO order (First In, Last Out), meaning that the first started session is the last stopped.
- Three phase charging not supported by vehicle
If a vehicle is allocated three phases, but does not use more than one phase, it will be relocated to a single phase. This prevents phase 1 being excessively utilized in these scenarios. If a charger has not used more than one phase for the past 5 minutes, it can at any time be moved to a single phase. The charger is only moved when required.
- Preferred charge phase
When allocating a single phase to a charger, the charger will prefer its offline phase.
- Sticky phase
A charger that is allocated a single phase, will keep this phase for as long as possible. If a charger needs to be moved to balance the installation, the last connected charger is moved first.
Chargers that have been offline in a charging session, will be locked to its offline phase for the duration of the session. This will prevent chargers from switching phases when going offline/online. If the charger is locked to a phase with no available power (due to manual or automatic available current setting), it will not provide current until there is available current on the chargers offline phase
- Sticky single phase
If a vehicle in an installation supporting three phase charging has for some reason been allocated a single phase, e.g. due to 3 to 1 phase switch current, it will stick to single phase charging for the duration of the session. The reason for this is to limit the number of stop/start commands sent to a charger. We try to limit this as some vehicles abort charge sessions after multiple stop/start cycles.
The applied power management scheme will also be a factor in this. For Zaptec Pro installations, there are three different power management options.
- Manual power control
This is the basic power management tool, where the system adheres to the setting: Charging system circuit breaker (A). Additionally, it is possible to reduce available current on one or more phases. This can be helpful if there are known loads on the same circuit that are not from charging stations.
- Scheduled power control
The scheduled power control allows the installation owner or service provider to create a time schedule of the available power of the installation. For more information, see this article.
- Automatic power management (APM)
By installing an APM ( available models might differ between countries), it is possible to balance the load on the installation towards the buildings main fuse or similar.