The Ultimate Guide to DC Fast Charging

The Ultimate Guide to DC Fast Charging

Charger speed will be your top concern if you’re considering making the switch to an electric vehicle (EV). If you own an EV, the amount of time it takes to charge it might have a big impact on your daily schedule. The quickest method of charging an electric car is DC fast charging, which is why public EV charging infrastructure must have it. DC fast charging stations are perfect for both short-term visitors who wish to maintain their car’s battery life and EV drivers who must swiftly charge their vehicles while traveling large distances.

WHAT IS DC FAST CHARGING?

Direct current (DC) electricity is stored in an electric vehicle’s battery, while alternating current (AC) power is supplied by the electric grid. An onboard charger is a device that powers an electric car by converting AC power to DC power and then distributing that power to charge the battery. The amount of time it takes to charge an EV is significantly decreased by DC fast charging, which skips this onboard charger and charges the battery directly. This was made possible by the DC Charging Station’s process of converting AC electricity to DC power before sending it to the vehicle. Compared to AC-type charging, DC fast charging can enable EV charging significantly more quickly.

DC fast charging is also referred to as level 3 charging, DCFC (Direct Current Fast Charging), quick or ultra-speed charging, etc.

It’s important to understand the various EV charging speed levels and how DC fast charging fits into the bigger picture before getting into the specifics of DC fast charging.

WHAT ARE THE DIFFERENT LEVELS OF EV CHARGING?

Level 1 EV Charging

At the moment, Level 1 charging equipment for electric vehicles is the slowest. A regular 120 volt AC outlet is the straight plug-in location for a level 1 EV charger. The average power output is from 1 to 1.8 kW, which increases your electric vehicle’s range by about 3 to 7 miles per hour. Needless to say, if you plan to use your electric car regularly Level 1 type chargers are very slow and not very practical. Level 1 charging is not possible in regions of the world outside of North America and Canada where normal household voltages are higher—230 volts in Europe, for example.

Level 2 EV Charging

Level 2 charging is the next faster than level 1 charging. In North America and Canada, a level 2 electric car charger requires a 208 volt to 240 volt connection; in Europe, it requires a 230 volt (single phase) or 400 volt (three phase) connection. Depending on your geographical location, a Level 2 charger can generate power outputs ranging from 3 kW to 22 kW, which translates to a range of 10 to 75 miles per hour of charging. The most common kind of EVSE (Electric Vehicle Supply Equipment) is a level 2 charging station, which is available in many public places, including homes and companies.

Both Level 1 and Level 2 EV chargers deliver AC power to the electric vehicle.

Level 3 EV Charging – DC Fast Charging

The fastest and most effective kind of EV charging is level 3 DC fast charging. A normal electric car may be charged within 15 to 60 minutes at a Level 3 charging station since they are built to produce more power at quicker speeds than Level 2-type chargers. The outputs range from 15 kW to over 350 kW. In complete contrast to Level 1 or Level 2 EV charging, DC fast charging use commercial-grade three-phase connections to transmit DC power straight to the electric vehicle’s battery. Let’s take a closer look at the variations.

WHAT IS THE DIFFERENCE BETWEEN AC AND DC FAST CHARGING?

Electric vehicles can be charged in two ways: directly current (DC) using a Level 3 DC fast charger, or alternating current (AC) using a Level 1 or Level 2 type charger. DC charging is quick charging, whereas AC charging is sometimes described as slow. There is always AC electricity flowing from the electric grid. Nevertheless, as batteries can only store DC power, the energy required to power your EV must be kept in reserve in the battery. In light of this, the placement of the AC power conversion to DC is the primary distinction between AC charging and DC fast charging. With DC fast charging, the conversion occurs at the charging station in advance of the power being delivered to the vehicle, circumventing the limitations of the onboard charger for electric vehicles and helping higher power delivery. In AC charging, the AC power is converted within the vehicle by the on-boarding charger, a process that takes time. Level 3 DC charging is quicker than AC charging because of this.

POWER VS VOLTAGE AND CURRENT

The DC charge voltage, which varies depending on the vehicle, battery, and state of charge (constant current (CC) start to constant voltage (CV) completion), etc., effects the DC charge current when the constant charge power (kW) is applied.

DC rapid chargers operate at a constant voltage, often between 200 and 1000 volts. The battery management system (BMS) of an electric car will make sure that it is charged within the battery’s tolerances at any given condition and will notify the EV charging station of the need.

HOW DOES DC FAST CHARGING WORK?

An electric vehicle (EV) using a DC fast-charging station interacts constantly to regulate the amount of power it draws. The rate at which your electric vehicle charges depends on several factors; however, we will primarily consider the charging station’s rate of charge, the electric vehicle’s acceptance rate, and the DC fast charging graph.

Rate of Charge of a DC Charging Station

The maximum output power of every EV charging station is measured in kilowatts (kW), which is commonly referred to as the charging rate or rate of charge. DC fast charging stations come in power outputs ranging from 15 kW to 350 kW; megawatt charging stations, which have the capacity to produce 1000 kW of power, are now under development. Though selecting a greater KW DC fast charger over a lesser kW one does not guarantee that the electric car can be charged more quickly, in general, the higher the KW, the faster the charge. This is where the charger’s rate of charge is affected by the electric vehicle’s acceptance rate.

EV Charge Acceptance Rate

An electric vehicle’s maximum power intake in kW is known as its charge acceptance rate (EVAR). When a DC fast charger cable is plugged into the automobile, the battery management system of the car notifies the charging station of this. A growing number of electric vehicles (EVs) on the market have better charge acceptance rates to enhance charging speed, despite the fact that some early models have very low charge acceptance rates.

Let’s take an example of an automobile with a 50 kW EV charge acceptance rate. That means whether it was being charged at a 50 kW, 100 kW, or even 350 kW DC fast charging station, the rate of charge would be about the same. Let’s examine another example that goes the opposite way: the Porsche Taycan can accept a peak charge of 270 kW thanks to its 270 kW charge acceptance rate. If you were to charge it at a 150 kW fast charging station, it wouldn’t reach its maximum. Since 150 kW is the charging station’s maximum rate of charge, it could only accept that much power.

DC Fast Charging Curve

Another important factor in deciding how quickly an EV charges is the DC fast charging curve. Every EV model has a different charging curve that dictates how much power it can hold when charging. An example of a common DC rapid charging curve is shown in the chart below. The horizontal axis of the figure displays the state of charge (SOC) of the EV battery over time, while the vertical axis displays the power output being drawn by the vehicle.

An EV will normally only charge for part of the charging cycle at its maximum pace. The electric vehicle will rapidly reach its maximum charging speed after establishing communication with the DC fast charging station. After that, it will gradually begin to consume less energy as the battery gets more charged; you can see that a steep drop-off happens when an EV battery is charged to 80% of its capacity. Since the charge speed from 80% to 100% is significantly reduced, the majority of EV Manufacturers and numerous studies advise charging the car to 80% of its battery capacity in order to help extend battery life and permit other EV drivers to utilize the charging station.

WHAT TYPES OF DC FAST CHARGING ARE THERE?

GB/T, Tesla Superchargers, CHAdeMO, and Combined Charging System (CCS) are the four types of DC fast charging connectors that are now in use worldwide. The DC connector that you can use to charge your electric vehicle depends on its make and model. There are two types of CCS: CCS2, which is used in Europe, and CCS1, which is used in North America. CHAdeMO is mostly for cars with Japanese brands. For recently launched models in North America and Europe, these manufacturers are switching to the CCS connector. The standard connector for the Chinese market is GB/T, and Tesla’s Supercharger is compatible with all Tesla vehicles outside of the European Union.

HOW FAST IS DC FAST CHARGING?

It is difficult to pinpoint exactly how fast DC charging is because there are many different kinds of electric vehicles with different battery capacity, a wide range of level 3 DC fast charging stations with multiple power outputs, and a number of other variables that can affect charging speed. However, based on the charger’s power output and the average EV’s kWh per 100 miles (kWh/100 mi), which is 34.6, we can estimate the number of miles of range an electric car can receive from a DC fast charger in under 60 minutes.

HOW MANY KW IS A DC FAST CHARGER?

An electric car may be charged more quickly with a DC fast charger whose output power (kW) is higher. Depending on the type, manufacturer, and installation location, the kW output power may change. The current market range for DC fast chargers is 15 kW to 350 kW. These can be split chargers, which divide the power to numerous charging cables and concurrently charge multiple EVs by sharing the charger’s kW power output, or standalone DC chargers, which supply the full kW power to a single plugged-in car. We at EVESCO offer DC fast chargers that range in power from 50 kW to above, both standalone and split.

CAN ALL EVS USE DC FAST CHARGERS?

There are several varieties of electric cars available; battery electric vehicles (BEVs), which are electricity-only vehicles, can typically be charged at DC fast charging stations. The amount of output power they can use will determine their EV charge acceptance rate. Certain electric cars can accept up to 300 kW of DC rapid charging. A recent test revealed that the Lucid Air Dream edition’s highest charge was 297 kW, whereas other models have a lower charge acceptance rate. The tiny battery capacity of some early BEVs and hybrid EVs (HEVs) prevents them from using DC rapid charging. When selecting an electric car, it’s critical to consider the battery capacity and charge acceptance rate to determine whether you can use DC fast.

IS DC FAST CHARGING BAD FOR AN EV BATTERY?

The short and easy response is no, not really. Technically correct, but widely held in the industry is the belief that the faster an EV battery is charged, the faster its capacity will deplete. Still, the Idaho National Laboratory study examined the impact of rapid charging on battery life. It demonstrated that there is little difference in the rate of EV battery capacity reduction when compared to Level 2 AC charging, even when DC fast charging is the only type of charging utilized.

Every battery in an electric car includes an advanced Battery Management System (BMS), which is programmed with particular settings to guard against damage to the battery. In addition to monitoring the battery’s temperature and regulating the charge acceptance rate, the BMS has the ability to reduce the rate of charge in order to safeguard the battery.

While DC fast charging can affect an EVs battery life, it is minimal and doesn’t damage the battery.

HOW MUCH DOES DC FAST CHARGING COST TO USE?

Due to the need for a three-phase connection, DC rapid charging stations are not appropriate for installation in residential settings; instead, they are intended for use in commercial and industrial settings. EV charging hubs, retail malls, business parking lots, gas stations, and service stations are just a few public locations where DC fast charging is available. The cost of public DC fast charging stations can vary significantly according on where they are located and when they are utilized. For instance, EV users in California should budget about 30 cents per kWh for Level 2 charging and 40 cents per kWh for DC fast charging.

However, in a another instance, we discovered that an electric vehicle user in Chicago was charged 29 cents per minute to use a DC fast charger; a 25-minute charging session only resulted in an additional 50 miles of range for $7.25. When the cost per kWh is permitted, Tesla charges an average of 28 cents per kWh for using their superchargers.

HOW CAN YOU FIND A DC FAST CHARGER?

As more and more electric vehicle drivers desire to swiftly charge their vehicles while driving, DC fast charging stations are becoming more and more common. A growing number of DC fast chargers are being deployed in public spaces, but where are they located? These EV charging stations can be located in a few different ways.

• Google Maps – more chargers are being added to google maps every day
• Plugshare – a helpful app for finding EV charging stations; it shows which ones are available and whether they are AC or DCFC
• Open Charge Map – a useful website that shows up to 500 charging stations per search
• DOE – The Department of Energy has a charging station locator for the USA, which shows not only EV charging stations but also Hydrogen, Bio-Diesel, and other alternate fuels
• EV charging networks – If you are a member of an EV charging network, then you can access their DC fast charging locations via their apps

SUMMARY

DC fast charging is becoming more and more necessary as the use of electric vehicles increases. DC rapid charging is crucial for the infrastructure of public EV charging stations. It will facilitate long-distance driving and provide a convenient place for households without at-home EV charging to charge their vehicles. When we convert bigger cars to electric power, DCFC will also be essential since these vehicles will need bigger batteries and faster charging times to function in practical settings.

Only 21,676 DC fast charging stations existed in the United States as of the end of 2021; a significant increase in this number is required if we are to meet the challenging goals set for the number of electric vehicles in use over the following five years.