Load balancing

Load balancing shares the power a site may draw between its chargers, so the site stays inside its grid limits. You set it up per location, in zones of chargers that share one limit.

At a glance

• Load balancing: the tab of the location that holds its zones, with Add new zone at the top.
• The zone row: Zone name, Meter number, Max Grid capacity and Min session power.
• Grid capacity Buffer, Chargers, Load distribution and Status: the rest of the zone's setup.

• Zone: the zone each charger of the site belongs to.
• Load & Phase: each charger's maximum current and power, and the phases it is wired to. A charger without power configuration, such as a DC charger, shows a dash.

Before you start: voltage system and power configuration

Every site needs its voltage system before you create a zone. Power configuration is needed in an Ampere zone and for the figures per phase, not in a kW zone.

The voltage system is the electrical supply of the location. It decides whether zones and chargers are treated as single phase or three phase:

• 3-phase 400V/230V - EU
• 3-phase 480V/277V - US Industrial
• 3-phase 208V/120V - US Commercial
• 1-phase 240V - Residential

You pick it the first time you save a charger's power configuration at a location, in Location voltage system. To change it later, click Edit on the Voltage system card of the location's Chargers tab.

For an Ampere zone, turn on Power configuration for each charger in Edit charger.

• Single, Split or 3-phase: whether the charger draws current from one phase, two phases or all three.
• Phase wiring: the phases the charger is connected to, for example L1-L2 for a split charger.
• Max current (A): the most current the charger may draw.
• Max power (kW): worked out for you from the voltage system, the current and the phases.

Set the phase wiring the way your electrician connected the chargers. If AC chargers are spread over L1, L2 and L3, then the phase wiring keeps the balancing per phase right. The phase monitoring of an Ampere zone adds up the chargers on each phase from these settings.

DC chargers

DC chargers go in a kW zone and need no power configuration. The zone takes their rated power from the charger model.

Leave Power configuration off in Edit charger. On the Chargers tab, Load & Phase then shows a dash for them. A site with DC and AC chargers mixed is set up as a kW zone too.

Create a zone

A load balancing zone is a group of chargers that share one limit.

1. Open the location and go to its Load balancing tab.
2. Click Add new zone.
3. Pick the LIMIT TYPE: kW, or Ampere for limits per phase.
4. Fill in the limits, the buffer and the load distribution.
5. Pick the chargers under Select Chargers.
6. Click Save.

With 300 kW of capacity and a 10 percent grid capacity buffer, the chargers of the zone share 270 kW.

If a charger is missing from Select Chargers, then it may already be in another zone. In an Ampere zone, a charger is also missing while its power configuration is off.

Dynamic or sequential

• Dynamic: the available power is shared between every charging session and shared again as sessions start and stop.
• Sequential: the first vehicles get full power in the order they arrived. Later vehicles get what is left, or wait until power frees up.

For example, a 400 kW zone has three 150 kW DC chargers. On Sequential, the first two vehicles get 150 kW each and the third gets 100 kW. On Dynamic, three vehicles get about 133 kW each.

On an AC site, a 90 kW sequential zone with six 22 kW chargers gives four vehicles 22 kW each. The fifth vehicle waits for power.

Set a schedule

Turn on Set schedule to give the zone another limit at set hours, for example in business hours.

1. Pick From and To in the location's timezone.
2. Enter the GRID CAPACITY for a kW zone, or the CURRENT LIMIT for an Ampere zone.
3. Tick the days under REPEAT SCHEDULE ON.

Hours outside the schedule use the zone's Maximum grid capacity.

Read the phase monitoring

An Ampere zone shows a Phase monitoring strip under its row, one block per phase.

• The amperes after the phase name: the maximum current of all chargers on that phase, added up.
• Load: that total as a share of the usable current, and the usable current itself.
• Buffer: the current held back by the buffer.
• Breaker: that total as a share of the breaker rating, and the rating.

If a phase's Load passes 100 percent, then the block turns red, so you see which phase is the bottleneck.

If the tab says some chargers are not in a zone, then add them to one. A charger outside a zone draws power the zone does not control.

Watch your zones live

This tab is where a zone is set up. To watch every zone of your network live, open Energy in the menu. It shows what each zone draws and which ones hold sessions back, see Load balancing.

Common questions

Why can I not select my charger in the zone? It may already belong to another zone. If the zone is an Ampere zone, then a charger with its power configuration off is not listed. If the model does not support smart charging, then the charger is not listed in any zone.

Should I use kW or Ampere limits? Use kW for DC chargers, or for DC and AC mixed, with no power configuration needed. Use Ampere when AC chargers are spread over L1, L2 and L3, with power configuration on for each one. Each phase is then balanced on its own.

What does the buffer do? It holds back a share of the capacity for the site's other use and for grid swings. At least 10 percent is recommended.

Can the site have a lower limit in business hours? Yes. Turn on Set schedule on the zone and set the hours, the limit and the days.

Why does my zone show only one phase? The location's voltage system is single phase. If the site is three phase, then change the voltage system on the Chargers tab and check the zone limits.