Zaptec’s patented load and phase balancing technology is at the core of our charging systems, ensuring safe, efficient, and fair charging for every user. Understanding this feature helps you get the most from your Zaptec installation, whether you’re configuring a new site or simply curious about how your charger works.
What is load and phase balancing?
Zaptec’s system automatically distributes available power across all connected vehicles and charging stations. This means:
- Dynamic phase allocation: Many EVs only charge on one phase, even if three-phase power is available. Zaptec’s system automatically distributes the load across all three powered phases. Adjusting as more cars connect, so everyone gets a fair share.
- Fairness and flexibility: As cars connect and disconnect, Zaptec reallocates power and manages queues, ensuring everyone gets a fair turn based on when they arrived.
- Real-time adaptation: With Zaptec Sense, the system monitors your building's total power use, reducing charging when other appliances are active and ramping up when more capacity is free.
All Zaptec Pro charging stations connected to the Zaptec Portal include this feature.
Want to see how load and phase balancing work?
Try our inCharge demo. Click on the charging stations and watch the system distribute the load to the different phases.
Or watch our 3-minute video for a glimpse into our patented technology, our aspirations and approach.
Is there a recommended number of Zaptec Pro chargers you can install in a single setup?
Zaptec's unique phase-balancing solutions ensure optimal use of all three powered phases. When multiple cars are connected, the charging process adapts to deliver power equitably to everyone.
To make sure everything works smoothly, Zaptec suggests not going over a certain number of chargers:
TN 400V 63A → Up to 30 chargers
IT 230V 63A → Up to 18 chargers
Following our recommendation ensures that all chargers in the installation can simultaneously charge. That being said, it's possible to install more chargers if you need to. It only affects the number of chargers that can charge at the same time.
Now, what happens if there's not enough power to start new charge sessions?
If there isn't enough power available to start a new charging session, the system queues sessions and starts them as soon as other sessions finish. Queued sessions follow the order they were connected; The first charger that started will be the last to stop. So, if your charging session started earlier, you'll get to charge before someone who started later. If the system has to stop charging sessions because there's not enough power, it stops the most recent ones first to be fair to everyone.
- For example, if the available power is reduced to less than 6A (1-phase, 1.4 kW, available per connected car by default) the system will start stopping charging sessions. The charger that started the earliest will be the last one to stop, ensuring that all cars get a fair share of charging time.
Trouble understanding? Picture a busy restaurant. Each customer is a car needing a charge. If there aren't enough chefs, orders go in a queue. Just like in the restaurant, the system serves cars based on arrival. If there's not enough cooking capacity (or power), it serves those who arrived first, ensuring fairness for everyone.
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.
If a vehicle in an installation supporting 3-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.
What happens if the chargers go offline?
The Zaptec Portal automatically optimises the offline current and phase selection for all chargers within an installation every hour (when online). This ensures 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.
Even if a charger goes offline, it remains functional, operating according to the preset offline settings. Depending on these settings, authentication may still be required for payment and access functionality, even during offline periods.
Please note that offline operation is not the charger's normal state, and while it may function properly, intentionally keeping the charger offline for extended periods is not recommended.
Power management options
Zaptec Pro installations offer three ways to manage power:
- Manual power control: Set the maximum current and adjust per phase if needed (can be helpful if there are known loads on the same circuit that are not from charging stations).
- Scheduled power control: Create time-based schedules for available power. Read more here.
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Automatic power management (APM): Use an APM to balance charging with your building's main fuse.
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