Load balancing for your EV charger: how dynamic load balancing works

In this article, you’ll learn how load balancing works, when you need it, and the difference between measuring via the smart meter’s P1 port and via CT clamps. You’ll also see how it works with solar panels, a 3-phase connection and multiple charge points.

What is load balancing for an EV charger?

Load balancing distributes the available capacity of your grid connection between your EV charger and the rest of your home or building. A meter continuously tracks how much power is already being used. The charger only gets what is left.

Example: you have a single-phase 35A connection, good for about 8 kW. Your charger can deliver 32A (7.4 kW). Switch on the dishwasher and the oven, and there is not enough left for full-speed charging. Without load balancing, the main fuse trips. With load balancing, the charging current temporarily drops to, say, 10A, then goes back up.

Static vs. dynamic load balancing

There are two types:

• Static load balancing sets a fixed maximum charging current, for example 16A. It’s simple, but you also charge slowly when there is plenty of capacity.
• Dynamic load balancing adjusts the charging current every few seconds to match actual consumption. You charge as fast as possible and as slowly as necessary.

In almost every situation, dynamic load balancing is the better choice. That is what the rest of this article covers.

Load balancing vs. smart charging

The terms are often used interchangeably. Load balancing protects your connection from overload. Smart charging goes a step further and also decides when to charge, for example on solar power or at a low dynamic electricity price. Load balancing is the foundation; smart charging builds on it.

Do you need load balancing?

In most homes with an EV charger: yes. A charger is often the biggest consumer in the house, and it typically runs in the evening, when the rest of the household also needs power. How tight it gets depends on your connection.

Indicative values based on 230/400V. Your installer determines what is safe and sensible in your situation.

Load balancing is almost always needed if you:

• have a single-phase connection;
• use a heat pump, induction hob, electric boiler or air conditioning;
• want to charge two cars or use multiple charge points;
• have solar panels and want to charge on your own solar power;
• want to avoid an expensive grid connection upgrade.

It is less necessary if you have a generous 3-phase connection, few other large consumers and mostly charge at night. Even then, load balancing offers peace of mind, because your consumption often changes faster than you think.

Multiple charge points and grid congestion

Companies, apartment buildings and car parks often have several charge points on a single connection. Load balancing then distributes the available capacity across all cars charging at that moment. When another car plugs in, everyone gets a little less. When one leaves, the others charge faster.

This is especially relevant in the Netherlands because of grid congestion: in many regions, a heavier connection is unavailable or only available after years of waiting. Load balancing lets you get the most out of the connection you already have.

In Flanders, the capacity tariff plays a role: part of your grid fee is based on your highest monthly peak. By smoothing out charging peaks, you keep that peak, and your grid tariff, lower.

For larger charging sites or buildings with several large consumers (battery, heat pump, PV), an energy management system such as ENNY-EMS is the logical next step. It controls not just chargers, but all flexible loads together.

Load balancing with the Xemex Smart Connect P1

The Xemex Smart Connect P1 is a compact P1 dongle that passes real-time measurement data from the smart meter to your EV charger. The charger uses that data for dynamic load balancing and solar charging. The dongle is developed and manufactured in the Netherlands.

How it works

The Smart Connect P1 reads the P1 telegram from the smart meter and converts it to Modbus TCP, a protocol many chargers understand natively. With a DSMR 5.0 meter, the charger receives new data every second; with DSMR 4.2, every 10 seconds.

Compatible chargers

The Smart Connect P1 works directly with chargers from brands including Peblar, Alfen, Schneider and Mennekes.

What sets the Smart Connect P1 apart

• Works with tricky meters: compatible with Sagemcom meters (S211, T211, XS212, XT211) and the Landis+Gyr E350, without an additional power supply.
• Flexible connectivity: via a network cable (Ethernet), Wi-Fi or a direct peer-to-peer connection with the charger.
• Splitter function: the P1 output lets you connect an existing P1 dongle or energy monitor at the same time. No need to choose between insight and smart charging.
• More than charging: the same data can also feed home batteries, micro-inverters, an EMS or a home automation system, via Modbus TCP or MQTT.
• Netherlands and Belgium: supports DSMR 4.2 and 5.0 (NL) and E-MUCS (BE), for single-phase and 3-phase meters.

Who is it for?

For homeowners, installation is carried out by an installer. Check our partner locations to find an installer near you. Are you an installer or charger supplier? Read on.