Load sharing is a method of dividing available electrical power between multiple EV charging outputs so the total stays within a defined limit. In EV charging, load sharing typically refers to how a charger (or a group of chargers) splits power between two connectors, multiple sockets, or multiple dispensers—ensuring safe operation while serving more vehicles from the same electrical supply.
What Is Load Sharing?
Load sharing allocates a fixed or dynamically calculated power budget across active charging sessions. It can apply at different levels:
– Within one charger (e.g., a dual-socket AC charger sharing a single supply)
– Across a cluster of chargers on one feeder
– Across DC dispensers sharing a common power cabinet
Depending on the system, load sharing can be:
– Equal split (each active connector receives the same share)
– Priority-based (one connector gets more power due to rules)
– Dynamic (power is redistributed as vehicles start/stop or demand changes)
Why Load Sharing Matters in EV Charging Infrastructure
Load sharing helps sites scale charging without oversizing electrical infrastructure:
– Enables two vehicles to charge from one charger without doubling the site connection capacity
– Prevents overloading breakers and feeder cables
– Improves utilization by keeping more connectors available
– Reduces CAPEX by minimizing switchgear and grid upgrade requirements
For destination charging (workplaces, hotels, retail), load sharing can significantly increase the number of usable charging points within a limited power budget.
How Load Sharing Works
Load sharing is implemented by controlling the maximum current or power delivered per output:
– The charger or controller monitors active sessions and total available capacity
– It assigns current limits to each connector (AC) or power setpoints (DC)
– When a second vehicle plugs in, the system reduces the first session or splits the available power
– When one vehicle finishes or disconnects, the remaining session can ramp back up
In networked systems, load sharing may be coordinated by a CPMS using OCPP setpoints.
Load Sharing in AC Charging
In AC EV chargers, load sharing usually means:
– A dual-output charger has a maximum total current (e.g., 32 A three-phase equivalent)
– If one connector is active, it can use most or all available capacity
– If two connectors are active, current is split according to a defined policy
Important practical detail: EVs may have minimum current requirements; if the split drops too low, a vehicle may pause charging.
Load Sharing in DC Fast Charging
In DC fast charging, load sharing often happens between dispensers connected to one power cabinet:
– The cabinet has a total kW rating (e.g., 300 kW)
– Power is allocated across dispensers based on demand and vehicle acceptance
– Allocation changes dynamically as battery acceptance tapers or new sessions begin
This enables high site throughput without dedicating full cabinet power to every dispenser simultaneously.
Benefits of Load Sharing
– Increases the number of usable connectors within limited site capacity
– Improves infrastructure efficiency and utilization
– Reduces risk of overload events and improves uptime
– Lowers installation and upgrade costs
– Supports scalable deployments where dwell times are long (destination and fleet sites)
Limitations and User Experience Considerations
Load sharing requires careful configuration to avoid poor charging outcomes:
– Two vehicles charging simultaneously will often charge slower than one
– Fairness rules matter (equal share vs priority vs first-come-first-served)
– Phase loading and cable limits must still be respected
– Communication failures need safe fallback behavior
If drivers expect full power on every connector, clear signage or app messaging can reduce confusion.
Related Glossary Terms
Load balancing
Load management
Dynamic load management
Power sharing
Site power limit
OCPP
Charge Point Management System (CPMS)
Power throttling
Charger utilization