Load Balancing
Load balancing in EV charging distributes a limited electrical capacity among charging vehicles and, in dynamic systems, coordinates that capacity with other site loads.
Why it is used
The sum of the connected chargers' ratings can be higher than the capacity available from a branch circuit, building connection, transformer, or site limit. Load balancing prevents every active connector from drawing its maximum at the same time. This can allow more charging points to share existing electrical infrastructure while keeping total demand within a defined boundary.
The controller can divide power equally, apply priorities, rotate access, or allocate energy using vehicle departure times and required charge. The useful result is not necessarily equal charging power: a fleet may need to protect an early-departing vehicle while slowing one that will remain parked longer.
Fixed and dynamic forms
Fixed power sharing divides a configured EV charging budget among active connectors. The budget normally stays the same even when the rest of the building's demand changes.
Dynamic load balancing measures or estimates changing non-EV demand and adjusts the EV budget accordingly. See Dynamic Load Balancing for the measurement, response, and fallback boundary.
Both forms are constrained by vehicle onboard chargers, EVSE limits, phase arrangement, minimum usable current, and communication delays. The design should define a safe limit if meters, controllers, or network links fail.
Important boundary
Load balancing manages capacity; it does not guarantee the lowest tariff, renewable-energy use, or participation in a utility grid program. Those objectives can be combined with load balancing, but they require additional inputs and control rules. A fixed time window is instead Scheduled Charging.
For the complete control architecture, see Smart Charging and Grid Integration.