DC fast charging station: which kW, how to calculate charging time, who installs one?

Short answer: A DC fast charging station converts AC from the grid into DC inside its own cabinet and feeds the battery directly, so it is not limited by the car's on-board AC charger. Common sizes for businesses are 40 kW (single connector) and 80–200 kW (usually two connectors). Charging time is roughly "energy to add (kWh) ÷ average power (kW)", but the car's maximum DC charging power and its charging curve decide the result. The DC connector standard in Europe and Turkey is CCS2. Installation needs a three-phase supply, enough connection capacity and, depending on power, often a capacity upgrade or a transformer; the work must be done by qualified electricians and engineers.

The basic difference between AC and DC is covered in our AC vs DC charging guide. This guide focuses on the DC station itself: power, charging time and infrastructure.

How does a DC fast charger work?

An EV battery charges with direct current. With AC charging, the car's on-board charger does the conversion and is usually limited to 11 or 22 kW. In a DC station the rectifiers (power modules) sit inside the cabinet. The station talks to the car, reads the battery voltage and the current it can accept, and adjusts its output.

That is why DC stations are large, heavy and need cooling: the power modules heat up and the cabinet is fan- or liquid-cooled. The key international standard for DC charging stations is IEC 61851-23.

How many kW? 40 kW vs 80–200 kW

• 40 kW (single connector): Suits cafés, restaurants, hotels, city car parks and small fuel stations where cars stay 30–60 minutes or longer. Lower infrastructure needs; wall-mounted or pedestal versions.
• 80–120 kW: The common range for shopping centres, hotels, fleet depots and urban charging hubs. Twin-connector models charge two cars at once.
• 160–200 kW: For motorway service areas and busy fuel stations with 20–30 minute stops. The highest infrastructure needs.

On twin-connector stations the total power is shared. With one car plugged in, it can take more power up to its own limit; with two cars, each gets less. How power is split depends on the model and software settings.

Three questions decide the power: How long do cars stay? How many sessions per day? What is your transformer and connection capacity? Without answers, buying the highest power often means paying for infrastructure you do not need.

How to calculate charging time

The rough formula:

Charging time (hours) ≈ energy to add (kWh) ÷ average charging power (kW)

Three things matter:

1. The car's DC limit: A car never exceeds its own maximum DC charging power. A car limited to 50 kW charges at about 50 kW even on a 200 kW station. Look for "maximum DC charging power" in the car's specifications.
2. Charging curve: The car only takes peak power within a certain state-of-charge window. Near full, especially above 80%, it cuts power sharply, so the last 20% can take almost as long as the first 80%.
3. The 10–80% rule: Manufacturers usually quote DC charging time from 10% to 80%. On a trip it is also the most efficient pattern: leave at 80% and charge again at the next stop.

Example: taking a car with a 60 kWh usable battery from 10% to 80% needs about 42 kWh.

• On a 40 kW station, if the car accepts the full 40 kW, average power stays slightly below 40 kW: roughly 1 hour to 1 hour 15 minutes.
• On a 120 kW station with a car that accepts 120 kW, the curve lowers the average: often around 30–40 minutes.
• If the same car is limited to 50 kW, it still takes close to an hour on the 120 kW station.

In cold weather power can be low until the battery warms up; see driving an EV in winter and EV charging time. For the effect of frequent DC charging on the battery, see does fast charging damage the battery.

CCS2 connector and compatibility

CCS2 (Combo 2) is a Type 2 AC connector with two large DC pins added below. Most DC-capable cars in Europe and Turkey use CCS2; the CHAdeMO connector found on some older models is now rare on new cars. On DC stations the cable is tethered, so drivers do not bring their own.

Both 400 V and 800 V cars are compatible with a station that has a wide DC output voltage range. For all connector types see EV charging cables and connector types.

Who installs a DC fast charger?

• Fuel stations: Give drivers range during a short stop and support shop and café sales.
• Hotels and restaurants: AC is often enough for overnight guests; for short restaurant visits DC makes the difference.
• Shopping centres and large stores: With 1–2 hour visits, 80–120 kW is usually enough.
• Fleets: Taxis, delivery vans, shuttles and rental cars need fast top-ups between shifts to stay on the road.
• Residential complexes and workplaces: Where cars park overnight or during working hours, AC is usually sufficient. A single shared DC unit can cover urgent needs. See EV charging for residential sites and workplaces and EV charging rules for buildings in Turkey.

Electrical infrastructure: transformer, capacity, cables

The biggest cost and time factor is usually the infrastructure, not the charger. In general:

• Three-phase supply: DC stations run on three-phase power. Input power is slightly higher than output because of conversion losses; the exact input (kVA and current) is in the datasheet.
• Connection capacity: Your capacity must cover the station and the building's other loads. A 40 kW unit can sometimes be added to an existing low-voltage connection with a capacity increase; 80–200 kW and multiple units often need a new or larger transformer and a medium-voltage connection.
• Network operator: Capacity increases and new connections are requested from the local distribution company, which assesses the connection point and transformer. This often takes longer than delivering the charger, so start here.
• Cables and protection: Cable size depends on current, distance, installation method and voltage drop. The board needs a dedicated breaker, the residual current protection the manufacturer requires and surge protection; earthing is measured.
• Site works: A concrete base for pedestal units, ducting, impact barriers, lighting and drainage.
• Communication: Ethernet or mobile data (4G) to connect the station to a charging network.

Design and grid connection must be handled by qualified engineers and electricians. Load management across several stations can reduce the capacity needed but cannot replace adequate infrastructure.

Paid charging, licensing and OCPP

Charging your own fleet or staff for free is private use. In Turkey, selling public charging is regulated by EPDK (the Energy Market Regulatory Authority) under the Charging Service Regulation: the station must belong to a licensed charging network operator's network, or the operator must hold its own licence. Roles, the 2026 amendments and pricing rules are explained in opening an EV charging station in Turkey; for networks see EV charging networks in Turkey.

To join a network the station needs OCPP (Open Charge Point Protocol). OCPP 1.6J is the widespread version; OCPP 2.0.1 is newer and more extensive. Ask your network operator which version it supports before choosing hardware. See what is OCPP.

Installation steps

1. Needs: Who will charge, how long do cars stay, how many sessions per day?
2. Site survey: Connection capacity, board, transformer, cable route and station location.
3. Network operator application: Capacity increase or new connection if needed.
4. Hardware: Power, number of connectors, wall or pedestal, OCPP version, IP rating, warranty.
5. Charging network: Contract and integration if you will sell charging.
6. Installation and commissioning: Base, cabling, board, connection, tests, network onboarding and a test charge.

DC fast chargers in our shop

We carry Bemis DC stations made in Turkey. The Bemis BEVDC 40 is a 40 kW unit with one CCS2 connector, in wall-mounted (600 × 320 × 900 mm) and pedestal (600 × 425 × 1770 mm) versions. The twin-connector Bemis BEVDC series comes in 80, 120, 160, 180 and 200 kW and charges two cars at once. Both run on 380–480 V three-phase, deliver 150–1000 V DC, support OCPP 1.6J / 2.0.1, RFID, Ethernet and 4G, and have an IP54, CE-certified enclosure.

Because installation varies by project, the product page shows the device price for reference and the final figure for device plus installation comes in a quote after a site survey. ENGN supplies Bemis from its store in Nilüfer, Bursa, and carries out surveys and installation in Bursa.

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