EV Charging Infrastructure · Lesson 3 of 5
Simultaneity, managed charging and demand limits
Connected load is the sum of charger nameplates. Operating demand is the power actually drawn at a particular moment. Load management can cap or allocate that demand according to site capacity, vehicle priority, energy need and departure deadline. It is a control strategy, not an assumption that vehicles will conveniently avoid charging together.
After this lesson, you should be able to:
- Calculate connected and managed charging demand
- Explain simultaneity without treating it as an arbitrary discount
- Design charging priorities around energy deadlines
What is physically and operationally happening?
Connected load is the sum of charger nameplates. Operating demand is the power actually drawn at a particular moment. Load management can cap or allocate that demand according to site capacity, vehicle priority, energy need and departure deadline. It is a control strategy, not an assumption that vehicles will conveniently avoid charging together.
A good scheduler continually asks: which vehicle needs how much energy, by when, and what power can the site safely provide? It should also define behavior when communication fails, vehicles arrive late or the site approaches its demand limit.
Sense
Measure site demand, charger status and vehicle or session needs.
Prioritize
Rank vehicles by departure, route, SOC or operating importance.
Allocate
Distribute available power within electrical and charger limits.
Recover
Define safe fallback and rescheduling when data or communications fail.
Connected load versus managed demand
A managed limit can preserve site capacity while charging energy is distributed over time.
Load management evidence profile
Illustrative demand. Values are educational, not Metro Power project-performance claims.
OPTIONAL ENGINEERING DEPTHLoad managementModel connected load, simultaneity, managed limits, phasing and future expansion.+
- Separate connected load from controlled demand
- Include existing site peak and reserve margin
- Respect vehicle acceptance, arrival and departure
- 01Build the one-line from utility service to connector
- 02Run vehicle-energy and managed-allocation scenarios
- 03Test controller fallback when communications or site metering fails
Site peak exceeds the enforced cap
Control latency, stale data or unmanaged charger
Compare meter, controller and charger timestamps
Vehicles miss departure targets
Allocation ignores energy deadline
Replay arrivals, initial SOC and priorities
- Vehicle schedule and session traces
- Site interval load and capacity study
- Controller logic and fallback test
Ten 60 kW chargers under a site cap
Ten DC chargers provide 600 kW connected load, but the approved charging cap is 240 kW.
- If all are equal, initial allocation is 240 / 10 = 24 kW each
- Prioritize vehicles with earlier departure or greater deficit
- Reallocate power when sessions finish or acceptance falls
- Confirm the total energy delivered within each duty window
“A 40% simultaneity assumption guarantees demand will stay at 40%.”
Only an enforced load-management limit or validated operating behavior can control demand. An unsupported factor is not protection.
Check what you can explain without looking back.
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Ten 60 kW chargers equal:
What keeps demand below a defined cap?
What should guide allocation?
Continue with the controlling references.
01Electric Vehicles for FleetsUS Department of Energy Alternative Fuels Data CenterFleet planning, equipment, operations and training considerations.
Open source ↗02State and Local Planning for EV Charging InfrastructureUS Department of Energy Alternative Fuels Data CenterCharging infrastructure planning framework.
Open source ↗03Open Charge Point ProtocolOpen Charge AllianceCurrent OCPP versions and capabilities.
Open source ↗Read the complete technical paper →