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Managed charging

Managed charging is the coordinated control of EV charging power and timing to meet specific goals such as avoiding electrical overloads, reducing energy costs, maximizing renewable use, or meeting fleet operational needs. It uses software and control logic to adjust charging in real time or according to schedules, typically through a Charge Point Management System (CPMS) and/or a load management controller.

What Is Managed Charging?

Managed charging means EV charging does not always run at maximum available power. Instead, charging is actively optimized based on constraints and priorities, such as:
– Site power limits (e.g., main fuse rating)
– Electricity tariffs and peak pricing periods
– Available onsite generation (e.g., solar PV) or battery storage
– Vehicle readiness requirements for fleets (departure times, required state of charge)
– Grid signals from the utility or aggregator

It is commonly implemented at workplaces, fleet depots, residential developments, and public sites with multiple chargers.

Why Managed Charging Matters in EV Infrastructure

As EV adoption grows, unmanaged charging can create high simultaneous demand that stresses building infrastructure and the grid. Managed charging helps:
– Prevent overload and nuisance trips at main LV panels and upstream protection
– Increase the number of chargers a site can support without expensive grid upgrades
– Reduce OPEX by shifting charging away from peak tariff periods
– Improve reliability and uptime by keeping the site within safe electrical limits
– Support sustainability goals by aligning charging with low-carbon or renewable energy availability

For fleets, managed charging improves operational certainty by ensuring vehicles are charged when needed while controlling total site demand.

How Managed Charging Works

Managed charging typically follows this logic:
– Measure or estimate available site capacity in real time (building load + EV load)
– Apply limits based on the site’s contracted capacity or protection devices
– Allocate charging current across chargers using priorities and rules
– Adjust charging power dynamically via the charger or vehicle interface
– Monitor sessions and update control decisions continuously

Depending on the system, control may be implemented through:
– Local controllers connected to energy meters and chargers
– Cloud-based CPMS rules and profiles
– Hybrid approaches (local safety limit + cloud optimization)

Common Managed Charging Strategies

Dynamic load management (site protection)
– Continuously adjusts EV charging power to stay below a site limit (e.g., 3 × 63 A)
– Prioritizes safety and prevents tripping main fuses

Scheduled charging (tariff optimization)
– Shifts charging to off-peak hours to reduce energy costs
– Useful for workplace overnight charging and residential sites

Priority-based allocation (fairness or critical vehicles)
– Distributes power based on rules: first come, first served; equal sharing; VIP vehicles; minimum guaranteed power
– Common in fleets with operational priorities

Renewables-aware charging
– Increases charging when solar output is high
– Reduces grid import and improves self-consumption

Peak shaving
– Caps total EV load during demand peaks to reduce demand charges and avoid capacity exceedance

Managed Charging vs Load Balancing

Managed charging (broader optimization)
– Can optimize for cost, carbon, renewables, and operational schedules
– May incorporate multiple constraints and external signals

Load balancing (capacity sharing)
– Typically focuses on distributing available power across chargers
– Often the core technical mechanism used inside managed charging systems

In many projects, load balancing is one feature within a wider managed charging strategy.

Key Requirements for Managed Charging

– Reliable measurement of site load (e.g., CT clamps, energy meter integration)
– Chargers that support power control (often via OCPP)
– Stable connectivity between chargers and the control system
– Clear configuration of limits, priorities, and safety margins
– Well-planned maintenance access for meters and controllers

Benefits and Trade-Offs

Benefits
– More chargers without upgrading the grid connection
– Lower energy costs through smart scheduling
– Improved site reliability and reduced trip events
– Better fleet readiness planning and reporting

Trade-offs
– Lower instantaneous charging power during peak constraints
– Requires metering, configuration, and ongoing monitoring
– Depends on communication reliability and correct commissioning

Load balancing
Dynamic load management
Charge Point Management System (CPMS)
OCPP
Main fuse rating
Main LV panels
Peak shaving
Time-of-use tariffs
Renewables integration
Smart charging