How is power divided between cars?
A pool car has to leave at 11 AM for a client visit. It is at 30%.
Next to it, a commuter's car at 70% will stand until 6 PM.
The questionShould both get the same power, and who decides?
| Uses all power | Needs extra data | Suits | |
|---|---|---|---|
| Equal shareeveryone gets the same | simple sites | ||
| First comeearliest car first | few cars | ||
| Prioritygroups ranked | user groups | fleets | |
| By departureneed and time | energy and time | mixed use |
Real systems combine rules, for example equal shares within a priority group.
A composed example, computed per phase: L1 carries every car and may carry 116 A. With priority by departure, the pool car gets 16 A, 11 kW, its maximum, and takes about 15 kWh by 11 AM, enough for the client visit. The others share the rest of L1 at 7.7 A each, and the commuter's car is still full before noon.
Where the data comes from
- From the driver: a departure time entered in an app or at the charge point.
- From the fleet system: booked trips of pool cars.
- From the car: with , the car itself can report the energy it needs and its planned departure time.
Without that data, a controller cannot plan by departure, and equal shares are the simple default.
Check your understanding
3 questions. Answer all of them to complete this stop. Each answer explains itself.
Which allocation rule needs departure times or energy needs?
To plan by departure, the controller has to know when each car leaves and how much it needs.
Why is equal share a common default?
Without information about departures, equal shares are simple and treat every car the same.
What happens to the pool car's share when it leaves at 11 AM?
Dynamic allocation recalculates when a car leaves; the freed power goes to the others.
- ISO 15118 International standard for the digital communication between car and charger, the basis of Plug & Charge. EV charging fundamentals, stop 08 Glossary
- Open Charge Alliance: What is new in OCPP 2.0.1? Whitepaper, version 1.0, March 2023. https://openchargealliance.org/wp-content/uploads/2024/01/new_in_ocpp_201-v10.pdf. Checked 09 Oct 2026. Licence: CC BY-ND 4.0.