Older apartment blocks, office parks, and mixed-use commercial properties share a common constraint that no amount of marketing can wish away: the electrical service was sized before EVs existed. Building owners who want to add charging are routinely told they need a costly service upgrade—new transformers, heavier cabling, larger panels—before a single charger can be energised. In many cases, that upgrade alone kills the project's payback.
Load balancing changes the arithmetic. It allows a building to add EV charging without expanding the site's total power envelope, by sharing existing capacity intelligently across chargers and other building loads. When paired with OCPP 1.6, load balancing becomes remotely configurable, monitorable, and adaptable to the way a building actually consumes power hour by hour.
This article explains where static load balancing stops being enough, how dynamic load balancing works in practice, and what OCPP 1.6 actually does inside that system.
Why fixed per-charger caps fail in real buildings
The simplest form of load management is static load balancing: each charger is assigned a fixed current limit, and that limit never changes, regardless of how many other chargers are active or what the rest of the building is drawing.
Static limits are cheap and deterministic, and for a small, uniform installation—say, two or three chargers on a dedicated circuit—they can be sufficient. But they break down in the exact environments where EV charging demand is growing fastest:
Capacity sits unused during low-demand hours. If a building's service has 80 A of headroom at night but each of four chargers is capped at 16 A under a static scheme, the site can only ever deliver 64 A—even when the building itself is drawing almost nothing.
One size does not fit all sessions. A car that needs 45 minutes of top-up and a car that will be parked for eight hours are treated identically under fixed caps. The short-duration session gets throttled unnecessarily; the long-duration session may finish with capacity still idle.
The building load is not constant. HVAC, lifts, kitchen equipment, and lighting all move the site's baseline consumption. A static limit set for peak building demand is over-conservative 90% of the time.
The result is a charging system that is technically safe but economically poor: more chargers installed than the site can actually utilise, and slower charging than drivers have reason to expect.
What dynamic load balancing does differently
Dynamic load balancing treats the entire installation—all chargers plus the building's other loads—as a single pool of available capacity. Instead of fixed per-charger caps, a controller continuously measures site consumption and reallocates the remaining headroom across active charging sessions, typically on a sub-minute cycle.
The operational difference is substantial. Under dynamic control, a site with 80 A of flexible headroom can deliver close to 80 A of charging when the building is quiet, then taper charger output gracefully when HVAC or kitchen loads rise. No single charger is permanently starved; the pool is redistributed as conditions change.
For a building owner, the practical effect is that more chargers can share the same service without triggering demand charges or compromising safety. One documented multifamily retrofit in Toronto installed 21 EV chargers on a service that conventional design would have limited to fewer units; with load management, the infrastructure was sized to eventually support 40 chargers on the same connection, avoiding a six-figure service upgrade and shaving roughly $24,000 off the project cost. That is not a marginal efficiency gain—it is the difference between a viable project and a shelved one.
For installers and distributors, the implication is equally direct: load-balancing capability is no longer a premium feature; it is the enabling condition for selling into the existing-building segment at all.
Where OCPP 1.6 fits: the communication layer behind smart charging
Load balancing does not happen inside the charger alone. A dynamic system needs three things working together: a metering point at the site's supply, a decision layer that calculates how much power each charger can safely receive, and a communication protocol that carries those decisions down to the hardware.
OCPP 1.6 is that communication protocol. Specifically, the Smart Charging feature profile within OCPP 1.6 allows a central system to send a SetChargingProfile command to a charger, defining the maximum current or power the charger may deliver over a given schedule. The charger reports back metering data and status; the backend uses that data to recalculate the profile and issue updates.
Two points are worth stating clearly for procurement teams evaluating OCPP 1.6 hardware:
1. OCPP 1.6 carries the instruction; the backend makes the decision. The protocol itself does not calculate load allocation. It is the transport layer between the charger and the CSMS (Charge Point Management System) or an OCPP-based energy manager. A charger that supports OCPP 1.6 Smart Charging can receive and execute profiles, but the intelligence that decides what profile to set lives in the backend software or building energy management system.
2. OCPP 1.6 Smart Charging is what makes remote, site-wide coordination possible. Without OCPP, load balancing is limited to local, hardware-level coordination—often a master-slave arrangement between chargers on the same circuit. With OCPP 1.6, the load-balancing scope expands to all chargers visible to the backend, regardless of circuit or physical grouping, and profiles can be updated dynamically without a site visit.
For a property with multiple parking areas, mixed charger generations, or an existing building energy management platform, that distinction matters. OCPP 1.6 turns load balancing from a fixed local configuration into a remotely manageable, software-defined capability—one that can evolve with the building's load profile and tariff structure without replacing hardware.
Regulatory pressure is making smart-charging readiness non-negotiable
The technical case for load balancing is increasingly reinforced by regulation. The revised EU Energy Performance of Buildings Directive (EPBD), approved in 2024, sets requirements for EV charging infrastructure in residential and non-residential buildings with more than three parking spaces, including pre-cabling obligations and—critically—the expectation that charging infrastructure be integrated into smart systems such as building energy management or load management systems. Pre-cabling definitions in member-state implementation guidance explicitly reference the inclusion of dynamic load management systems as part of the infrastructure that must be planned for.
In practice, this means a charger that cannot participate in site-level load balancing is not merely less efficient—it risks being non-compliant with the direction of building-code requirements in key European markets. For distributors and installers specifying equipment for retrofit projects, selecting OCPP 1.6 load-balancing-capable hardware now avoids stranded assets later.
What this means for charger selection
When evaluating AC chargers for existing-building projects, the load-balancing capability should be verified at three levels:
Local load balancing: The charger must support internal current limiting and coordination with other chargers on the same circuit, so the site can operate safely even if the backend connection drops.
OCPP 1.6 Smart Charging support: The charger must accept SetChargingProfile commands and report metering data at a resolution sufficient for dynamic control—typically 10–30 second intervals in backend-connected operation.
Certification and factory traceability: Load-balancing claims are only meaningful if the underlying hardware has been tested to the relevant safety and EMC standards. For European and North American projects, look for CE, TÜV, ETL, and FCC documentation, and prefer suppliers who can share test reports for the specific model.
This is where the distinction between a trading company and a manufacturing partner becomes visible. Zhuzhou Zopoise Technology Co., Ltd. (Zopoise) produces its wallbox AC charger line, such as the ZB20, with built-in load balancing and OCPP 1.6 communication as standard features. The ZB20 covers 7 kW, 9.6 kW, 11 kW, and 22 kW configurations, with ETL/CETL, FCC, TÜV mark, and CE certification documentation available.
Because Zopoise operates its own SMT, testing center, and aging workshop under one roof—and holds CNAS, UL WTDP, and TÜV witness lab qualifications—load-balancing functionality is validated on the same production line that ships the units. For distributors and CPOs requiring white-label software integration, custom load-balancing logic, or SKD/CKD delivery for local assembly, that vertical integration removes the ambiguity of sourcing a "load-balancing-capable" charger through a third party who cannot show the test bench behind the claim.
If you are scoping a retrofit project and want to confirm whether a specific AC charger configuration supports your site's load profile and OCPP backend requirements, the practical next step is to request the model datasheet and a sample test report—not a generic brochure.
