1.0 Background Information

1.1 Breaker Amperage

Circuit breakers are rated for a maximum amperage to prevent overloads. They don’t trip instantly but heat up over time before cutting power.

A 50A breaker carrying 51A may take seconds or minutes to trip.

At 55A, it heats faster and trips more quickly.

Think of a breaker like a fuse: the higher the current, the faster it reaches its “trip” temperature.

1.2 Constant Load Amperage

Electrical code limits continuous loads to 80% of a breaker’s rating. This buffer handles voltage fluctuations and brief power surges.

A 40A breaker supports a continuous draw of up to 32A.

Short spikes up to 40A are acceptable but not sustainable indefinitely.

1.3 EVSE & EV Roles

An EVSE (Electric Vehicle Supply Equipment) is the charging station, while the Electric Vehicle (EV) manages its own battery charging. When connected:

The EVSE declares a maximum current the vehicle may draw.

The EV decides its actual draw anywhere from 0A to that limit.

This dynamic allows vehicles to:

Optimize battery longevity by capping charge levels (e.g., 80 %).

Implement custom charging profiles (fast charge, trickle charge, time-of-day charging).

Plugzio’s system works by adjusting the maximum current each EVSE offers to its connected EV.

1.4 Plugzio non-EVSE Devices

Devices like the Plugzio Universal+ control box monitor power and switch outlets on or off. They do not communicate with EVs and cannot regulate charging current. For load balancing, these devices are assumed to draw 80% of their rated capacity (for example, 16 A on a 20 A circuit).

1.5 Plugzio EVSE Device

Plugzio EVSE devices are just like regular level 2 chargers you see on the market. EVSE models supported by Plugzio are the Plugzio Cando, Zerova AX series, Walbox Pulsar Plus, and StartCharge Artemis.

2.0 How Plugzio Load Balancing Works

Plugzio’s cloud-based platform acts as a central management system for your charging fleet.

Important: Each device must maintain a reliable internet connection so it can communicate with Plugzio’s cloud platform and support continuous load-balancing control.

Here’s how it operates:

Devices are grouped into a Load Balancing Group on the Plugzio dashboard.

Each group is assigned a virtual breaker limit.

The platform continuously monitors the total current draw of all devices in the group.

Plugzio dynamically adjusts each EVSE’s maximum output, so the combined draw never exceeds the virtual breaker.

This ensures safe, efficient charging across multiple vehicles and devices without overloading your electrical infrastructure.

Note: As a central management system, connectivity to the internet for the device is critical to the operation.

3.0 Load Balancing Parameters & Logic

3.1 Defined Parameters

Our load balancing system relies on these key inputs:

Breaker amperage – maximum allowable current for the circuit

Devices on the circuit

Current profile for each device:
- Minimum current (device-specific)
- Maximum current (the lower of breaker amperage or device’s rated max)
- Always-on current – Only applied in “Always On” mode

Current ratio – how much extra current to allocate when a device is actively charging

3.2 Operational Decisions

Using these parameters, Plugzio’s platform:

Evaluates whether a device can start a session without exceeding available amperage

If there isn’t enough current room, the new charging session is blocked

Regulates each device’s current draw between its defined minimum and maximum currents

A device is considered “drawing power” if it’s in an active charging session or running in always-on mode, ensuring accurate load accounting across the circuit.

4.0 Example Scenarios

4.1 Example A

Circuit parameters

Breaker amperage: 50A (40A continuous)

Devices: A, B, C

Device profiles

Profile Parameters	Device A	Device B	Device C
Maximum Current (A)	40	40	16
Minimum Current (A)	6	6	16
Always On Current (A)	10	10	16
Ratio	1	2	0

Scenario outcomes

If only Device A is on, it can draw the full 40A.

If Devices A and B turn on:
- Allocate each device’s minimum (6A + 6A = 12A)
- Remaining 28A is split by ratio (1:2), so Device A gets 9A and Device B gets 18A
- Final currents: Device A = 15A, Device B = 24A

If Devices A and C turn on:
- Allocate minimums (6A + 16A = 22A)
- Remaining 18 A goes entirely to A, ratio (1:0)
- Final Currents: Device A = 24A, Device C = 16A

If all three devices turn on:
- Allocate minimums (6 + 6 + 16 = 28A)
- Remaining 12 A split by ratios (1:2:0), so A = 4A, B = 8A, C = 0A
- Final currents: A = 10A, B = 14A, C = 16A

If a device is set to always on, its always-on current is reserved before balancing:
- If Device C is set to always-on (16 A) leaves 24 A for A and B
- If Device A is set to always-on (10 A) leaves 30 A for B and C

4.2 Example B