Every site owner installing EV chargers eventually runs into the same wall: the electrical supply. A single fast AC charger is easy to fit. Eight of them on the same feed, all pulling full power at once, is a different problem — and usually the first place a project’s budget balloons, because “just upgrade the grid connection” is slow, expensive, and sometimes not even possible on short notice.
Dynamic load balancing is the software answer to that hardware constraint. It’s one of the least visible features in a charge point management system (CPMS), and one of the most consequential for what a site can actually afford to install.
What Is Dynamic Load Balancing?
Load balancing means keeping the combined power draw of every connected charger under the site’s available electrical capacity, automatically, without tripping breakers or exceeding the utility contract.
There are two ways to do this:
- Static load balancing divides the available capacity evenly (or by fixed priority) across all connected chargers, whether or not they’re actually in use. It’s simple, but it wastes capacity: if 8 chargers each get a fixed 12.5% share, a single car plugged in overnight still only gets an eighth of the available power.
- Dynamic load balancing measures real, live demand — how many vehicles are actually charging, at what power, alongside the building’s other loads — and reallocates capacity between chargers in real time, second by second.
Why It Matters for Site Owners
The business case is almost always about capacity you already have, not capacity you have to buy:
- Skip or delay a grid upgrade. A workplace or retail site with a 100A three-phase supply and no dedicated EV allowance can often still install 6–8 AC chargers, because dynamic balancing shares what’s actually free at any given moment instead of reserving a fixed slice per charger.
- Avoid nuisance trips. Static, worst-case sizing means either over-provisioning the electrical service (expensive) or risking a tripped main breaker the day every bay happens to be occupied at once (disruptive, and a liability concern for a commercial site).
- Scale without re-permitting. Adding chargers 9 and 10 to a dynamically balanced group is a software configuration change. Adding them to a statically sized system usually means re-opening the electrical design.
- Share power with the building, not just between chargers. More advanced (building-level) load management also watches the site’s non-EV load — HVAC, lighting, production equipment — and gives chargers only what’s left over, which matters most for retrofits into existing commercial buildings rather than greenfield sites.
Static vs. Dynamic, Side by Side
| Static Load Balancing | Dynamic Load Balancing | |
|---|---|---|
| Basis for allocation | Fixed share or fixed priority order | Live metering of actual demand |
| Responds to | Nothing — same split whether 1 or 8 cars are plugged in | Number of active sessions, their state of charge, building load |
| Typical update rate | Set once at commissioning | Continuous (seconds) |
| Capacity utilization | Low–moderate; leaves headroom unused | High; capacity is shared only when actually needed |
| Best fit | Small, low-traffic sites where simplicity matters more than throughput | Multi-charger sites, fleets, depots, and any retrofit onto an existing electrical supply |
Where the CPMS Comes In
Load balancing isn’t a property of the charger hardware alone — it’s coordinated centrally, which is exactly the job of a charge point management system like ChargeOS. In an OCPP-based deployment, this typically works through:
- Smart charging profiles (OCPP
SetChargingProfile), which let the CPMS instruct each charger, in real time, what maximum current or power it’s allowed to draw right now. - A group/cluster model, where chargers on the same electrical circuit or feed are logically grouped so the platform can compute and enforce a shared cap across all of them.
- Priority rules, so a site can decide, for example, that a fleet depot’s overnight vehicles charge first, or that visitor chargers yield to staff chargers during business hours.
- Live health and load visibility, so the site operator can see utilization trends and decide whether — and when — an actual capacity upgrade is worth the cost, instead of guessing.
A Practical Example
Consider a workplace site with an available 100A three-phase supply reserved for EV charging (roughly 66 kW usable after margin) and eight 22 kW AC chargers.
- Statically split: each charger gets a fixed ~8.25 kW. Every plugged-in vehicle charges slowly, all the time, even if only two bays are occupied.
- Dynamically balanced: with two cars plugged in, each can draw up to the full 22 kW (well within the 66 kW cap) and finish charging in roughly a third of the time. As more vehicles plug in throughout the day, the platform reallocates automatically, and only when all eight bays are occupied simultaneously does per-charger power drop toward the static-case minimum — a scenario that, on most sites, is the exception rather than the rule.
Same eight chargers, same electrical supply, dramatically better real-world throughput.
What to Ask Before You Buy
If you’re evaluating a CPMS or a charger fleet and load balancing matters to your site (it usually does, past 2–3 chargers), a few questions are worth asking any vendor directly:
- Is load balancing dynamic (live metering) or static (fixed split)?
- Can it balance across chargers from different manufacturers, or only within one product line?
- Does it support building-level integration (reading non-EV load), or only EV-to-EV balancing?
- What happens to an active charging session if the group hits its cap — does it throttle gracefully, or interrupt?
- Is the allocation logic configurable (priority tiers, time-of-day rules), or fixed by the vendor?
Getting this right is what determines whether a site can grow from 2 chargers to 20 without a single electrical contractor visit in between.
