Load balancing is how a group of EV chargers shares one limited power supply. A controller monitors the site’s total load and continuously adjusts each charger’s output, so every connected car charges without overloading the main supply. It is the technology that makes EV charging workable in apartment car parks, workplaces and depots, where the grid connection could never feed every charger at full power at the same time.
Key Takeaways
- Load balancing divides a limited supply between chargers so nothing overloads.
- Dynamic balancing follows the building’s real load; static and scheduled methods are simpler.
- It is essential for apartment, workplace and fleet sites, optional for a single home charger.
- Balancing shares power fairly; it does not increase any charger’s maximum speed.
The problem load balancing solves
A building’s supply was sized for the building, not for a row of cars. Ten chargers rated 7.4 kW each would call for 74 kW if all ran flat out — more than many small commercial supplies can spare, especially at times when the building itself is busy. Upgrading the grid connection is slow and expensive. Load balancing instead treats the available power as a shared pool and divides it between the cars that are actually plugged in, minute by minute.
Three ways to share the power
| Method | How it works | Best for |
|---|---|---|
| Static balancing | A fixed cap is split evenly between chargers, whatever the building is doing | Small sites with predictable loads |
| Dynamic balancing | A meter measures the building load in real time and gives chargers whatever capacity is spare | Mixed-use buildings, homes with a tight supply |
| Scheduled or priority | Charging is shifted by time window, or some users and bays get priority | Fleets and depots with fixed departure times |
Our article on dynamic load balancing for a home wallbox covers the single-house version. The multi-charger version uses the same principle, with a site controller and networked chargers reporting through a standard protocol such as OCPP. Before choosing a method, a site needs its numbers: our guide to load calculation basics for buildings shows how to work out what a supply can support.
What drivers and site managers notice
- Cars may charge more slowly at peak times, then speed up as the building or the car park empties.
- Every plugged-in car still receives energy; balancing shares power rather than switching chargers off in turn.
- RFID cards or an app identify users, so energy can be billed or reported per driver.
- The main breaker stays within its limit, which protects the whole building’s supply.
Balancing does not create power, and it does not raise the top speed of any single charger. We cover that point directly in does load balancing increase EV charging speed?
Equipment built for shared sites
The EV-AC03201T is a dual-connector AC station that shares up to 43 kW between two Type 2 connectors (22 kW per connector), with OCPP 1.6J for networked management and RFID for user access — power sharing between its two connectors is load balancing in miniature. For smaller shared sites, the EV-ACT3204PE 22 kW wallbox adds RFID and app control. See the commercial EV charging page for site-level options.
Frequently Asked Questions
Does load balancing slow my car down?
At busy times, yes: your share of the pool is smaller while many cars charge at once. For overnight or all-day parking, the total energy delivered by departure time is usually unaffected.
Do I need load balancing for one home charger?
Usually not. It becomes relevant when several chargers share a supply, or when one charger must coexist with a small home supply. The home case is covered in the dynamic load balancing article linked above.
What happens if the network connection drops?
Systems differ. Well-designed controllers keep enforcing the last safe limits locally, so charging continues at a conservative rate. Ask the manufacturer how their system behaves offline before you buy for a large site.
Related Reading
- What Is Dynamic Load Balancing, and Why Does Your Wallbox Home Charger Need It?
- Does Load Balancing Increase EV Charging Speed?
- Adding EV Chargers to a Building: Load Calculation Basics
- Wallbox Home Charger Features Explained: Display, Scheduling, and Load Management
