What is the DC fast charger model?
The DC Fast Charger setup is designed to simulate a fast-charging plaza with multiple DC chargers. These chargers:
Operate at high charging power (e.g. 150 kW per socket by default).
Can be actively controlled by the EMS (Energy Management System).
With this model, you can:
Estimate expected energy use (kWh).
See when energy is needed over the day.
Understand how many vehicles can be charged.
Simulate EMS control to prevent unwanted peaks above your contracted power (e.g. by delaying or throttling charging).
For example, if total demand would exceed your contracted power, the EMS can temporarily delay certain charging sessions and resume them later when there is available capacity.
Key parameters
When you configure a DC fast charging plaza, the following parameters are important.
Number of DC chargers
Represents the total number of DC stations on the charging plaza.
Each DC charger has 2 sockets by default, so:
1 charger → 2 sockets
5 chargers → 10 sockets, etc.
This determines how many vehicles can charge in parallel.
Total number of expected vehicles per day
Enter the expected number of vehicles that will visit the plaza per day.
It is normal that more vehicles may arrive than there are sockets available.
If all sockets are occupied when a vehicle arrives, that vehicle is counted as not able to charge in the simulation (this shows up in the report).
Maximum power per socket
This is the charging power per socket during an active charging session.
Default: 150 kW per socket.
You can override this with a user-defined value if your hardware or grid constraints differ.
This value has a major impact on:
How fast vehicles are charged.
The peak power the plaza may request from the grid (and thus on the contracted power risk).
Vehicle percentages (large, medium, small)
You can specify the expected mix of vehicle types to get a more realistic estimate of energy demand:
Large vehicles (e.g. heavy passenger cars, electric trucks)
Typical battery size: 120–200 kWh
Medium vehicles (e.g. standard passenger cars)
Typical battery size: 70–120 kWh
Small vehicles
Typical battery size: 40–70 kWh
By adjusting the percentage per category, the model approximates:
Average energy per session
Total daily kWh demand
How likely you are to hit power or capacity constraints.
Charging days and times
Define on which days charging is allowed (e.g. weekdays only, 7 days, etc.).
Define the time window for charging (e.g. 07:00–22:00).
The model will then only schedule charging sessions within these windows, which directly affects:
The distribution of demand across the day.
The alignment with other loads controlled by the EMS.
Understanding the report
The DC fast charger report contains four charts plus some summary values to help you understand the impact of EMS control.
Chart 1 – Requested vs. delivered energy (kWh)
This chart compares:
Yellow line – The requested energy:
Total kWh needed to fully satisfy charging demand (what vehicles would like to charge).
Blue line – The actual delivered energy:
The kWh that is actually supplied, after EMS control and curtailment.
If the blue line is below the yellow line, it means:
Some energy demand cannot be fully met because the EMS is curtailing charging to stay below the contracted power limit.
Chart 2 – Actual power consumption (kW)
This chart shows the actual power drawn (kW) over time:
Includes the effect of EMS control (e.g. throttling or delaying charging).
Helps you check if your power peaks are kept below the contracted power.
You can use this chart to:
Verify that EMS control is functioning as expected.
See when power peaks occur and how high they are.
Charts 3 and 4 – Plaza usage and socket occupancy
These charts provide additional insight into how intensively the plaza is used:
Socket occupancy
Shows how many sockets are occupied at each time step.
Helps to see whether you are over- or under-dimensioned in terms of the number of chargers.
Vehicles arriving without a free socket
Shows how many vehicles arrive but cannot start charging because all sockets are occupied.
Indicates potential queueing or lost charging sessions in reality.
Use these charts to decide whether you need:
More DC chargers or sockets, or
Different charging windows or EMS strategies.
Summary metrics in the report
At the bottom of the report (or next to the charts), you will see three key totals.
Total (incl. control)
The total kWh actually used when the EMS is actively managing the chargers.
This reflects realistic energy consumption under your configured control rules and contracted power limits.
Total (excl. control)
The total kWh that would be needed if the chargers were not controlled by the EMS.
Represents the unconstrained scenario where every vehicle could charge at full power whenever it arrives.
This value allows you to compare “ideal demand” vs. “EMS-controlled reality”.
Total consumption (missed)
The total kWh not delivered due to EMS control.
Calculated as the difference between:
Total (excl. control) and
Total (incl. control).
This shows:
How much energy demand is curtailed to keep power below the contracted limit.
The trade-off between grid / contract protection and charging convenience for users.
With these parameters and charts, you can configure realistic DC fast-charging scenarios, assess the impact on your grid connection and contracted power, and decide whether you need to adjust charger power, EMS strategy, or plaza size.