Electric Vehicle Load Management & Power Sharing. Load balancing ev charger

Wireless load balancing: an innovation for EV chargers

In Sweden alone, chargeable vehicles – which include pure electric cars and hybrids – already account for almost 10% of the country’s privately owned cars and is a market which has grown 40% over the last 12 months.

As the number of EVs increases, so does the demand put on the electricity grid – and this is where load balancing comes in.

The reason load balancing is a must-have

Load balancing is a Smart way of controlling electricity flows to optimize EV charging and manage energy peaks.

Energy peaks typically occur in the morning – when everyone is brewing coffee and using appliances at the same time as they get ready for the day – and in the evening when everyone comes home from work.

Without load balancing, there is a high risk that the system will be overloaded, leading to blown fuses.

electric, vehicle, load, management, power, sharing

Load balancing provides stability and reduces the burden on the grid by managing peaks and prioritizing when power should go to someone’s home and when it should be used to charge the car.

The future of load balancing is wireless

Swedish electrical appliance supplier, Eldon Installation AB, manufactures charging boxes for electric cars.

“All home electric chargers require load balancing to ensure the fuses in the house aren’t blown. That requires the installation of an energy meter which communicates with the charger,” says Reine Lönn, who runs the Chargers division at Eldon Installation AB.

The challenge Eldon Installation AB sees is in laying a cable to connect the charger to the meter.

“Chargers are typically installed where the car is parked and that is not necessarily always near or on the house itself. Digging up the driveway to lay a 25m cable from the garage to the house is not an option, but with a wireless connection, there is no problem.”

Eldon Installation AB has recently launched a charger with a built-in wireless Modbus connection. Modbus is the communication protocol which cables use to send information from one device to another. With wireless Modbus, the charger and energy meter can talk to each other in milliseconds enabling wireless load balancing.

“We also see the same benefits for public or office parking spaces,” adds Reine. “To start off with maybe there are only spots for three electric cars, which is fine, but charging stations are being installed at an ever increasing rate and as soon as you have more, fuses will start to blow. That’s when the same problem arises. You need load balancing and the energy meter needs to communicate with the chargers but you don’t want to dig up the whole car park to make it happen. And this is where an electric charger with wireless Modbus capabilities comes in.”

W-Modbus by LumenRadio

Wireless Modbus – or W-Modbus – replaces the Modbus RTU cable with a reliable wireless mesh. It eliminates time-consuming installation planning and cabling. The perfect solution for enabling wireless load balancing for electric chargers.

Utilize the power of W-Modbus

Contact Erik to find out more about wireless solutions for load balancing

Electric Vehicle Load Management Power Sharing

Thanks to power sharing and load balancing for electric vehicles, EV chargers will be able to safely power more than one EV per home. As more people adopt EVs, they’ll be needing better charging technology to charge two vehicles at once, for example.

Today, we introduce these functions, explain how they work, illustrate them with examples, and list some of the benefits and advantages of having these features on your EV charger.

What Is Power sharing?

Most Australian homes feature a single-phase electrical connection with an electrical capacity of up to 63A. In most cases, homes can easily power your stock standard charger that requires 32A, but charging two EVs simultaneously using separate chargers is a slightly more complex process.

Powering two level 2 EV chargers that both require 32A, would require you to dedicate the entire electrical infrastructure of the home to EV charging (as using our example above of a standard house having 63A, 32×2 = 64A). In most cases, you would not even be able to turn your lights on. This is where EV charging with power sharing comes in.

Power sharing allows you to set up a maximum power input for each of the chargers you install (i.e. if you install 2). This means that in a 63A home, you could configure the 2x EV chargers to demand a maximum of 40A, leaving you with 23A to spare for powering regular appliances. This is an energy management feature that allows you to maximise EV charging capabilities for two electric vehicles with the same electrical capacity, while controlling the power demand within safe a range for the electrical system.

However, you should keep in mind that with power sharing you are essentially manually assigning a maximum capacity to be used by the EV chargers. This will leave a maximum capacity for you to be used on other appliances that you must not exceed in order not to trip the main circuit breaker. In our previous case example, you should be careful not to exceed the 20A for each charger.

How Does Power Sharing Work?

When EV charging with power sharing is active, the shared load of all connected EV chargers will not exceed the maximum capacity set by the user. This allows you to safely charge two EVs simultaneously and use appliances at home as you regularly do.

The way EV charging with power sharing works is the following:

All connected EV chargers are communicating via Wi-Fi or Ethernet. When a single charger is active, it can charge the EV at full capacity with no problems to the electrical infrastructure of the home. When the second EV is connected, both chargers will monitor the charging rate and limit the shared load to the configured maximum capacity, set by the user.

Power Sharing Practical Example

Let us better understand this feature with an example.

For EV charging with power sharing let us consider a home with a 63A electrical capacity and two 7.2kW single-phase EV chargers connected to different circuits. In this case, the homeowner wants to set 48A for EV charging and leave 15A available to power other appliances in the home while EV charging.

When only one EV is connected, the charger will supply full power, drawing 32A. After the second EV is connected, both chargers communicate and the load is distributed equally between EVs, leaving 24 amps per EV to deliver a charge rate of 5.5kW for each of them.

If the family installed two EVs without power sharing capabilities, they could only charge a single EV at full rate since as soon as the second electric car is connected (demanding 32A), the main circuit breaker of the house would trip. This would interrupt the charging process and result in a poor user experience. The alternative approach in this scenario would be to upgrade the cut-out fuse to 80A or even 100A if allowed by the utility. This could be a longer permit process and could involve extra expenses in electrical infrastructure upgrades. We usually don’t recommend this as it’s quite costly.

What Is Load Balancing?

Many people confuse power sharing with load balancing. This function is relatively similar to EV charging with power sharing since it adds a layer of flexibility to the EV charging process by considering the limited electrical infrastructure of the home, but there are two main differences between them.

  • Load balancing considers the electrical capacity of the home and automatically adjusts the charging rate to fit within the availability power capacity at any given time.
  • Load balancing can be used when charging a single EV or multiple electric vehicles.

One of the useful applications of load balancing is when you have high demand load applications at home such as heat pumps, electric showers or washing machines. These appliances demand a lot of power, which is why using them in combination with an EV charger could potentially result in tripping the main circuit breaker (even if you are charging a single EV). By integrating load balancing into the equation, your system will reduce EV charging accordingly to safely supply power to these other appliances as needed.

In summary, load balancing for electric vehicles is a function that dynamically balances the load of the EV charger (or chargers) and the load demanded by all active appliances in the house to fit within the electrical capacity of the home.

electric, vehicle, load, management, power, sharing

How Does Load Balancing Work?

The way load balancing works for EV chargers is very interesting.

First, a separate energy management device measures power demand at the home considering all connected appliances to the service panel. This dynamic energy monitoring works like a Smart metre that is connected as well to the EV charger. This needs to be installed by a qualified electrician.

While the energy management device reads the energy usage at the home, the charger demands a load equal to or lower than the remaining electrical capacity (after factoring in the consumption for all appliances). In other words, the other appliances of the house are prioritised over EV charging.

Load Balancing Practical Example

For this example, we will examine how the system will behave for the same home in different times of the day. For the first case, let us consider a morning time with a single EV at home (figure 3.a), while for the second case, let us consider a night time with two EVs connected to the house (figure 3.b).

In figure 3.a, only one EV is connected, but the family is using all types of appliances and demanding around 50 amps in household consumption. This only leaves the EV charger with around 10 amps available, delivering a low charging rate of 2.3kW to the EV.

Then, at night (figure 3.b), a second EV is connected and the home appliances only demand a load of 20 amps as the people are sleeping. In this case, an available capacity of 40 amps or 9.2kW is left available to share between the two electric cars. Depending on the programming of the charger, the power can be shared equally between EVs or adjusted according to the state of charge of each EV.

As can be seen, the system dynamically adjusts to the needs of the user depending on how many loads are connected and how many cars need to be charged. This ensures that protection devices will not unnecessarily trip due to excess demand.

Advantages of Load Balancing and Power Sharing Capabilities

Load balancing and power sharing are excellent functions. Some highly advanced EV chargers featuring load balancing capabilities include the Zappi EV charger and the Wallbox Pulsar Plus, while the Tesla Gen 3 EV charger features power sharing technology, all of which revcharge stock. You can shop our chargers on our store page.

When using load balancing and power sharing, you will be able to enjoy many interesting advantages. Some of the most important ones are the following:

  • No need to upgrade the electrical infrastructure at your home.
  • Families can own and charge multiple EVs simultaneously.
  • High-consuming appliances (water pump, HVAC systems, and others) can be used with no fear of tripping the main breaker (load balancing exclusive)
  • Load balancing for electric vehicles can be used in a workplace to offer EV charging to employees without compromising the power availability of the building. (Non-residential)
  • EV charging with power sharing can be used to easily charge EV fleets. (Non-residential)

Load balancing in three levels

We call our load balancing for NANOGRID™. It’s a Smart power solution for overload protection over the power grid. With our system, you do not have to worry about getting the main fuse tripping. We have three different types of load balancing depending on your needs.

NANOGRID™ CTEK Grid Central (CGC)

With our external CTEK Grid Central cabinet, the load balancing system can also take other important consumers into account such as lifts, ventilation, lighting, etc. The system keeps track of other consumers via transformer measurement. Our Grid Central is a compact device cabinet that contains a charge control unit, energy meter and transformer measurement equipment.

NANOGRID™ Local

Our local load balancing is managed directly from the charge control unit into a selected “master device”. All devices are connected with ethernet cables to a common switch. The load balancing can then be set as desired and against a given value or main fuse. Our local load balancing works without an internet connection.

NANOGRID™ Home

With our popular load balancing for home use, you never have to worry about the main fuse tripping. An additional energy meter is mounted at the incoming mains, which then “talks” via modbus communication to the wallbox. We set the main fuse data into our charge control unit, the charging is then dynamically adjusted and the house always has priority.

Load balancing with external device cabinet, NANOGRID™ – CTEK GRID CENTRAL (CGC)

CTEK GRID CENTRAL is a long-term investment that enables reliable and carefree electric car charging. CTEK GRID CENTRAL is a separate device that contains all load balancing technologies. This box manages charging stations and also external loads such as lighting, ventilation, elevator and more. With our unique load balancing system, important electrical equipment in the parking environment can be prioritized and the power grid is protected from overload. When several electric cars are charging simultaneously, overload in the mains can occur. In some cases, the fuses will trip. With CTEK GRID CENTRAL, a costly redevelopment of existing power grids is avoided.

The system measures the service that enters the property and controls the power outlets in the charging stations. The size of the main fuse is fed against the grid control board. This is all our system needs to ensure the stability of the property network.To install charging stations as well as CTEK GRID CENTRAL, a qualified and trained electrician is required.

NANOGRID™ – CTEK GRID CENTRAL, perfect for: Parking lot, shopping centres, real estate, industries, etc.

“We have increased the number of EV charging points every year. Mainly due to the increase in the number of electric cars, but also we always try to be one step ahead, to meet future demand. CTEK was selected because we felt they could deliver a solid and reliable charging solution, with high technological performance standards.”

– Karl-Johan Wall, Hufvudstaden, NK parking, Stockholm

Load balancing – between several devices, NANOGRID™ – Local

When several electric cars charge at the same time, load balancing can be required to avoid overload. In case of overload, the system automatically adjusts the power of the charging stations or alternatively turns off them completely. With load balancing enabled, the electric car charge will be limited to the maximum allowable current. If the power is controlled, charging will take a little longer, but no fuse will trip.

The load balancing function is based on Ethernet communication between the wallboxes. To each device, power and Ethernet cable is connected at the time of installation. The stations are connected in a common switch. The system does not need to be connected to the internet to work, local communication between the devices is sufficient for full functionality.

NANOGRID™ – Local, perfect for: Tenant, company, parking etc.

Stockholm Parkering has confirmed that all new developments will install EV charge points in 100 percent of the total parking spaces, with the remaining parking spaces being ‘EV ready’. The CTEK solution is fully scalable, enabling Stockholm Parkering to lay down the foundations for further growth and expansion over time.

– Stockholm Parkering

Load balancing at home, NANOGRID™ – Home

With our load balancing for your home to CHARGESTORM CONNECTED, you not have to worry that the main fuse will trip. The power of the charger will automatically be set at no risk for overload. With CHARGESTORM CONNECTED, you can make an option with a load balancing feature at home. The solution means that an additional energy meter is mounted on incoming feed. This energy meter is wired to the charging station’s control board.

When the load balancing is activated, it automatically works and the car’s charge is adjusted and optimized all the time, depending on how much power the house draws. Our load balancing solution protects your home’s power grid from overload while providing efficient charging.

NANOGRID™ – Home, perfect for: Villa, summerhouse, guesthouse etc.

“The first EV charging products we always talk about are CTEK products. And that is because when we recommend CTEK, we know we are delivering our customers technology that they can have confidence in. They have great products and deliver excellent technical support.”

– Thomas Svensson, CEO, AV-Line

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How load balancing works

Electric car load balancing is a vital component of the new infrastructure. It allows charging stations to share available power supply among charging cars, ensuring charge even when the charging station has limited available power supply.

Load balancing provides Smart charging, which sets and regulates charging management across charging stations to maximize efficiency while avoiding overload or increasing power supply costs. It guarantees that an electric car in a family, restaurant, or company fleet is prepared for each day’s problems in the same way that traditional gasoline and diesel-powered vehicles are. CTEK’s NANOGRID, an advanced load balancing solution

NANOGRID-Load Balancing system is one of the many great innovations provided by CTEK. Its function is the Smart power distribution from a cluster of electric vehicle charging points when they are being accessed by not only one but several electric vehicles, intending to ensure the total incoming supply capacity is not exceeded.

When used in a cluster, CTEK’s NANOGRID provides scalable load balancing to guarantee that the incoming electrical supply is not overburdened due to excessive charger use. No matter if it is at your home, office, or commercial property, NANOGRID provides you Smart overload protection with adjusted and optimized power availability. To provide efficient charging, NANOGRID comes in three different modules, to make efficient your home, office, and commercial EV charging requirements.

Unique architechture

NANOGRID’s architecture is unique in that it automatically analyses available capacity and determines how much power a vehicle requires. Following the completion of the analysis, the charging units will distribute electricity based on the maximum capacity of the connection. Electric cars may always be charged using this technology, even if the installation has limited capacity.

The load balancing method is based on the wall boxes communicating over Ethernet. When the system is set up, each device is given power and an Ethernet cable. A shared switch connects the stations. The system does not need to be linked to the internet to function because local communication between the devices is sufficient.

The system monitors and manages the power outlets in the charging stations as well as the grid that enters the property. The primary fuse size is fed into the grid control board. This is all our system needs to assure electricity stability throughout the property network.

What is load balancing and how does it help charge EV fleets?

We’ve seen an amazing surge in the uptake of electric vehicles (EVs) within the last 18 months, especially within the commercial space. As the EV revolution continues to grow, so too do the opportunities available for companies to optimise these new electric assets to work for your business.

We’ve talked about range anxiety before. With each week, more charging infrastructure is installed, and battery range is improving, which helps this. One more area to consider is how to ensure vehicles are optimally charged when they’re sharing a constrained electricity grid. And there’s technology that can help us make best use of the power available – load balancing your charge stations.

What is load balancing?

Electric vehicles can place a high demand on the local grid connection. For sites where there’s a constraint on the supply capacity, the electrical installation can’t always provide the required amount of power to charge multiple EVs simultaneously. However, there are several solutions available that distribute the available power supply more evenly.

The aim with load balancing is to deliver a safe charging infrastructure that makes best use of the available capacity without overloading it, vastly reducing the need to invest in complex and costly grid reinforcement works, or pay for a higher maximum connection rate.

The different load balancing types

1) Standard load balancing

Some chargers have dual sockets, meaning they can charge two EVs simultaneously. If there’s sufficient capacity to bring two supply cables to these chargers, they can essentially operate independently, with each socket charging at the maximum rate. However, there’s a cost benefit in connecting a single supply cable, with two connected vehicles sharing power across the two sockets.

Benefits of standard load balancing Drawbacks of standard load balancing
Shares available charge between charging EVs equally. Potentially reduces charging speeds when more than one EV is charging at the same time, increasing charge times.
Allows multiple vehicles to charge with the minimum amount of hardware, reducing cable and install costs. Only ever has access to a fixed energy capacity.
electric, vehicle, load, management, power, sharing

2) Smart charge network

Up to 100 chargers can be connected in a Local Area Network, in a similar manner to how computers are networked in an office environment. No internet connection is required and no additional hardware. This means the system can react rapidly and has no central point of failure. Once networked, a maximum charge rate limit can be applied to the network to avoid overloading the supply.

The aim with a Smart charge network is to charge vehicles as quickly as possible, so the power delivered is only shared when required, with vehicles charging at their maximum rate otherwise. When vehicles leave the site, or reach a full charge level, the extra power is redistributed, increasing the charge rate to other vehicles.

3) Active (or dynamic) load balancing

This feature allows an individual charger, or a Smart charge network, to be connected to a metering device that measures the electrical load that the EV chargers may be sharing. Typically, this would be an office building or factory. If the demand from the building increases, then the meter will register this and send a new, lower, limit to the network of chargers. This increases the limit again when the demand on the building reverts to previous levels, meaning there’s always an optimum safe level of power available for charging EVs.

Benefits of active load balancing Drawbacks of active load balancing
If electricity consumption of connected buildings or devices drops, the available power for EV charging increases. Requires a compatible meter on-site.
Reduced requirement for additional (expensive and disruptive) upgrade works. Increased complexity during commissioning process.
Can be configured to work with existing Energy Management Systems.
Can account for additional power from on-site generation, for example wind or solar.

4) Demand Side Response

It’s possible to take charging to the next level, by moderating charge levels in response to an external input. When it comes to EV charging, Demand Side Response – explained here in its original form of taking advantage of electric assets. might take the form of changing charging times or speeds to take advantage of lower cost electricity prices. It’s also technically possible to provide services to the National Grid, by lowering charging speeds across multiple chargers when the grid is constrained. These practices are still in formative stages for many suppliers, though are innovative ways to think about the flexibility of fleet charging.

5) Vehicle-to-Grid

V2G gets a lot of column inches but the reality is that it still has some development to do before it becomes mass market. Vehicle-to-Grid charging allows bidirectional power from the grid to the car and vice versa. If you have enough batteries connected to the grid then they can be used as an asset for all the things that grid connected batteries can be used for such as Frequency Response, Energy Trading (Arbitrage) or Peak Shaving.

This promising technology has several hurdles but looks set to become mainstream over time. It’s most likely to be adopted by charge at base fleets, or places where people leave cars for predictable lengths of time such as airports, but the technology is improving, and costs are coming down.

Take the next step

Interested in electrifying and optimising your fleet? Find an expert EV partner to identify which approach suits your current and future plans for electrifying your business.

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