One morning in the car park, fully understood
The last car in the car park is full. The meter at the connection shows the building's night load, nothing more.
Twenty cars charged today. Not one driver changed a setting.
The questionCan you explain everything the controller did today?
The day in seven moments
Fourteen cars, 154 kW demand, 80 kW available: a peak turned into a plateau.
Stop 01The building runs up; gives the chargers what is left.
Stop 02New limits travel as ; the cars' onboard chargers follow.
Stop 03The pool car leaves first, so it gets more: allocation by departure.
Stop 04One phase near its fuse while the total is fine: four single-phase cars on L1.
Stop 05The grid operator's signal at the evening peak; the cheaper price after 10 PM.
Stop 06Forty charge points on 120 kW: planned for energy, not for peak power.
Stop 07
Seven moments, one connection. turns limited power into enough energy for every car.
Where to go from here
OCPP in depth follows the messages behind charging profiles, Energy and grid integration the grid beyond the site, and Battery storage how a battery can widen a tight connection. See all learning paths.
Check your understanding
4 questions. Answer all of them to complete this stop. Each answer explains itself.
What did load management change at 8:30 AM?
Same energy, longer time: the demand of 154 kW became a plateau at the limit.
How did the new limits reach the cars at 9:10 AM?
Backend to charger with OCPP, charger to car through the cable's control signal.
Why was L1 close to its fuse at 10:15 AM?
All charge points had been connected in the same order, so single-phase cars landed on L1.
What did the grid operator's signal at 6:30 PM do?
Control is temporary and keeps a minimum; the remaining energy came after 10 PM.
- OCPP Open Charge Point Protocol: the open protocol between a charger and its operator's backend. EV charging fundamentals, stop 03 Glossary
- Load management Shares a site's grid connection between the cars charging at the same time. EV charging fundamentals, stop 04 Glossary
- Dynamic load management Load management that measures the load at the connection and gives the chargers the room that is left, moment by moment. Stop 02 Glossary
- Charging profile An OCPP message that sets a limit in amperes or watts for a station, for new sessions or for one session, valid for a time or as a schedule. Stop 03 Glossary