How to Choose the Right Door Energy EV Charger for Different Application Scenarios?

When it comes to EV charging equipment, higher power is not always better. For residential complexes, hotels, and office buildings, vehicles typically remain parked for several hours, making low-power AC EV chargers sufficient for replenishing energy. In contrast, highway service areas, taxi depots, bus terminals, and logistics parks prioritize vehicle turnover efficiency; if power output is insufficient, the costs associated with queuing times and operational losses can far exceed the initial equipment investment.

Therefore, when selecting an EV charging solution, buyers should look beyond mere equipment price or rated power. Factors such as vehicle battery capacity, parking duration, daily mileage, the number of vehicles charging simultaneously, grid capacity, connector standards, backend management, and future scalability should all be incorporated into the initial planning phase.

Global charging infrastructure continues to expand rapidly. Data from the International Energy Agency (IEA) shows that over 1.3 million new public charging points were added globally in 2024, representing a year-on-year increase of more than 30%. Meanwhile, global EV sales have surpassed 17 million units, accounting for over 20% of total new vehicle sales. As the adoption of electric passenger cars, buses, logistics vehicles, and heavy-duty trucks accelerates, charging sites are evolving from simple installations of a few charging piles into comprehensive energy and operational systems.

This article examines practical application scenarios to guide you in choosing between Door Energy’s W Series, C Series, D Series, U Series, and H Series. The discussion focuses on fixed-installation EV chargers and charging station equipment.

I. Calculate Actual Charging Needs Before Selecting an EV Charging Solution

1. Do Not Equate Rated Power Directly with Actual Charging Speed

The power rating listed on an EV charger indicates the device's maximum output capability; however, a vehicle's ability to continuously accept that power depends on its battery management system (BMS), state of charge (SOC), battery temperature, and charging curve.

For instance, even if an EV is connected to a 160kW DC fast charger, the device will not continuously output 160kW if the vehicle's maximum DC charging power is limited to 100kW. Furthermore, once the battery SOC exceeds approximately 80%, vehicles typically reduce charging power to protect battery safety and longevity. Charging time can be roughly estimated using the following formula:

Charging Time = Energy Required ÷ Average Effective Charging Power

Assuming a vehicle needs to replenish 60 kWh of energy, the theoretical times for equipment with different power ratings are as follows:

The results above are engineering estimates and do not guarantee that all vehicles will achieve these specific speeds. Actual deployments must also account for factors such as vehicle power limitations, charging curves, ambient temperature, and power sharing.

2. Determining Required Power Based on Parking Duration

Parking duration is one of the most readily available and valuable data points for equipment selection.

If hotel guests stay for an average of 8 hours, replenishing 7–11 kWh per hour is usually sufficient to meet daily needs. Conversely, if a taxi can only stop for 30 minutes between shifts, a higher-power DC fast charger is required. As for heavy-duty electric trucks, which may have battery capacities reaching hundreds of kilowatt-hours and short parking windows, high-power equipment-such as the U Series or H Series-is necessary.

Therefore, a sound EV charging solution should begin with vehicle operational planning rather than a product catalog.

II. Residential, Community, Hotel, and Office Buildings: Prioritizing AC EV Chargers

1. Why is blindly pursuing fast charging unnecessary for long-duration parking?

Residential areas, hotels, office buildings, and employee parking lots share a common characteristic: long vehicle dwell times. The goal in these scenarios is usually not to fully charge a vehicle in 20 minutes, but rather to complete the necessary charging before the owner departs.

In terms of total lifecycle costs, AC EV chargers generally entail lower equipment costs, less demanding power distribution requirements, and reduced maintenance complexity compared to high-power DC equipment. Furthermore, multiple low-power charging points can cover more parking spaces, preventing the queuing bottlenecks that often occur with a limited number of high-power units.

Projections from the U.S. Department of Energy indicate that by 2030, Level 1 and Level 2 AC charging will account for approximately 80% of the energy supplied to light-duty electric vehicles, while public DC fast charging will account for about 20%. This demonstrates that, although DC fast chargers garner more attention, slower AC charging remains the backbone of the daily charging ecosystem.

2. How does the Door Energy W Series suit destination charging needs?

The Door Energy W Series offers power ratings of 7 kW, 11 kW, and 22 kW, making it suitable for residential complexes, hotels, communities, office buildings, and employee parking lots.

The W Series supports Type 2 or GB/T connectors and offers various activation methods, such as Plug & Charge, RFID, and App control. OCPP 1.6 comes as standard, with OCPP 2.0 available as an option, allowing project operators to integrate the units into charging management platforms.

Additionally, IP65 and IK08 protection ratings make the units suitable for outdoor installation. With an operating temperature range of -30°C to +50°C, the equipment is well-suited to the typical climatic conditions of most overseas markets.

3. How many units should be installed for a community project?

Suppose a community has 200 parking spaces and currently 40 electric vehicles (EVs), with each vehicle requiring an average daily charge of 15kWh. The total daily demand would be:

40 vehicles × 15kWh = 600kWh

If each 7kW unit operates for an average of 6 hours per day, assuming 90% efficiency:

7kW × 6 hours × 90% = 37.8kWh/day

Theoretically, approximately 16 units would suffice to meet the daily charging requirement of 600kWh. However, to accommodate overlapping charging times, future growth in EV ownership, and equipment maintenance, the project could consider installing 18–20 charging points, or installing the necessary power distribution infrastructure first and adding units in phases. ## III. Shopping Malls, Hospitals, and Public Parking Lots: Balancing Parking Duration and Commercial Turnover

1. Commercial Scenarios Require More Than Just One Power Rating

Vehicle dwell times vary significantly across shopping malls, hospitals, hotels, and urban public parking lots. Some users stay for over three hours, making 22kW AC chargers suitable, while others stay for only 30–60 minutes and prefer 60–160kW DC chargers.

Therefore, commercial projects often benefit from a mixed configuration.

These ratios serve as planning guidelines; final proportions should be adjusted based on actual parking records and vehicle data. For instance, hospital parking durations are typically longer than those at urban transport hubs, so the proportion of AC equipment can be increased. Conversely, areas with rapid turnover-such as airport pick-up zones or transport hubs—should feature a higher proportion of DC equipment.

2. Which Commercial Projects Suit the C Series?

The Door Energy C Series offers power ratings of 20kW, 30kW, and 40kW. This series is ideal for locations where vehicles stay for approximately 1–3 hours and users desire faster charging speeds than standard AC options provide.

The C Series supports wall-mounted or pedestal installations and offers an output voltage range of DC 200–750V. It is suitable for small-scale public fast-charging sites, retail parking lots, community charging hubs, and light-duty charging stations.

It is important to note that the 20kW, 30kW, and 40kW models belong to the C Series, not the D Series. For commercial sites with limited grid capacity, moderate parking durations, or a need to control initial investment costs, the C Series strikes an optimal balance between charging speed and power distribution costs.

3. How to determine if an advertising screen is needed?

The 120kW or 160kW DC EV chargers equipped with a 32-inch advertising screen are better suited for shopping malls, hotels, hospitals, and public parking lots. The screen can display charging instructions, site services, brand content, or commercial advertisements.

However, an advertising screen is not a necessary feature for every project. If the unit is located in a rear parking area with low traffic, the standard D Series may be more cost-effective. Conversely, when the charging unit is situated at a commercial entrance or in a high-traffic area, the screen enhances visibility and provides additional operational value.

IV. Urban Fast-Charging Stations and Highway Service Areas: Choosing Between Door Energy D Series and U Series Based on Turnover Rate

1. Door Energy D Series: Suitable for standard public fast charging

The Door Energy D Series offers power ratings of 60kW, 80kW, 120kW, and 160kW. This series is designed for locations such as shopping malls, parks, hotels, hospitals, public fast-charging stations, and highway service areas.

The D Series offers an output voltage range of DC 200–1000V and a maximum output current of 250A, supporting OCPP, RFID, and mobile app integration, with optional POS terminal support. For commercial charging operations, features such as MID-certified energy meters, remote communication capabilities, and backend platform connectivity are also essential.

2. Measuring Revenue by "Vehicles Served per Parking Space per Day"

Assuming a fast-charging space operates for 14 hours a day, with an average vehicle occupancy time of 45 minutes plus a 15-minute buffer for entry/exit, payment, and connection, the total turnaround cycle is approximately 60 minutes.

The theoretical service capacity is:

14 hours ÷ 1 hour/vehicle = 14 vehicles/day

If the average energy delivered per vehicle is 45kWh, the daily electricity sales volume for a single parking space is approximately:

14 vehicles × 45kWh = 630kWh/day

If lower-power equipment is used, increasing the average occupancy time to 90 minutes, the same space could theoretically serve only about 9 vehicles. Therefore, in areas with high land costs or heavy traffic flow, increasing charging power may be more cost-effective than adding more parking spaces.

However, higher power output also increases requirements for power distribution capacity and demand charges. Since some commercial electricity tariffs calculate demand charges based on the highest average power consumption over a 15-minute interval within the billing cycle, revenue cannot be calculated solely based on the volume of electricity sold.

3. The U Series is Suitable for High-Speed and High-Turnover Scenarios

The Door Energy U Series is an ideal choice when vehicles require a substantial charge within 15–30 minutes, or when the charging site serves public buses, logistics fleets, or electric heavy-duty trucks.

It is important to note that the vehicles must support the corresponding high-voltage and high-power charging platforms; otherwise, the additional power capacity may not translate into shorter charging times.

V. Public Buses, Logistics Parks, and Electric Heavy-Duty Trucks: Determining Site Power Based on Vehicle Scheduling

1. Fleet Projects Require Calculating "Total Energy" and "Peak Power"

While public charging stations primarily serve vehicles arriving at random, fleet charging operations are highly scheduled. Project planners can usually obtain data on vehicle counts, route mileages, return times, and State of Charge (SOC) in advance, enabling the design of a more precise Door Energy EV Charging Solution.

For example, consider a logistics fleet of 30 electric vehicles, each traveling 200 km per day with an average energy consumption of 0.3 kWh/km. The total daily energy requirement is:

30 vehicles × 200 km × 0.3 kWh/km = 1,800 kWh

If the charging window is 8 hours and the system's overall efficiency is 90%, the minimum average input power required is approximately:

1,800 kWh ÷ 8 hours ÷ 90% ≈ 250 kW

However, 250 kW represents only the average demand. If all vehicles connect simultaneously, the project must also account for the number of charging connectors, per-vehicle power requirements, peak load, and vehicle departure schedules.

2. Reference Requirements for Different Fleet Types

The data in the table is intended for preliminary planning and does not represent specific vehicle model specifications. During the engineering design phase, actual battery capacity, maximum charging power, and charging curves provided by the target vehicle manufacturers must be used.

3. Why is dynamic power allocation better suited for large fleets?

If ten independent 400 kW units were installed for ten parking spaces, the theoretical peak load would reach 4 MW; however, in most scenarios, ten vehicles would not simultaneously charge at a continuous 400 kW rate. Such a design would not only increase equipment investment costs but could also result in underutilized power distribution capacity.

The Door Energy H Series utilizes an architecture featuring a centralized main cabinet and multiple terminals, enabling dynamic power allocation based on vehicle State of Charge (SOC), departure schedules, and charging requirements.

Door Energy H Series units feature an efficiency of at least 96%, an output voltage range of DC 200–1000V, and a maximum current of up to 1600A. The system supports 250kW, 500kW, or 600kW charging terminals, with the 600kW terminal utilizing liquid cooling technology.

Through dynamic power allocation, vehicles that return early and are scheduled for imminent departure receive priority high-power charging, while remaining vehicles continue charging at lower power levels. This approach satisfies vehicle scheduling requirements while maximizing the utilization rate of the main cabinet.

VI. Six technical indicators must be evaluated when constructing charging stations

1. Interface standards and vehicle compatibility

Different markets and vehicle models may utilize different charging interfaces. Door Energy DC equipment can be configured with CCS1, CCS2, GB/T, or CHAdeMO connectors based on project requirements, while AC equipment supports Type 2 or GB/T configurations. Before procurement, compile a vehicle inventory and verify at least the following information:

2. Grid Capacity and Peak Load

A site's existing transformer capacity is not entirely available for EV charging; lighting, HVAC, production equipment, and building loads also consume capacity.

For example, if a commercial building has a 1,000 kVA transformer and other peak loads reach 650 kW, simply adding four 160 kW DC chargers would theoretically add 640 kW of load—likely exceeding available capacity. Solutions include power limiting, off-peak charging, dynamic load management, or phased capacity expansion.

3. OCPP and Backend Management Capabilities

For hotels, fleets, and public operators, EV chargers should not be isolated units. OCPP enables remote status monitoring, user authorization, order logging, tariff configuration, fault diagnosis, and platform integration.

Backend management becomes increasingly critical as the number of units exceeds ten. Without a unified platform, O&M staff struggle to timely detect issues such as offline status, communication errors, connector faults, or low utilization rates.

4. Outdoor Protection and Environmental Conditions

Outdoor equipment must be evaluated against factors such as rain, dust, impact, salt spray, temperature extremes, and altitude. Door Energy offers series with IP54, IP55, or IP65 protection ratings and IK08 impact resistance.

However, an IP rating does not mean the equipment can be installed just anywhere. Site engineering must still address drainage, bollards, shading, cable management, and maintenance clearance.

5. Payment, Metering, and User Identification

For residential and enterprise projects, RFID or app-based authorization can be used. Public charging stations, however, may require a combination of apps, RFID, POS terminals, and electricity meters that comply with local metering regulations.

If the target audience includes occasional visitors, an overly complex registration process could reduce equipment utilization rates. Therefore, payment methods should be tailored to the specific user type rather than simply maximizing the number of features.

6. Maintenance and Future Expansion

A reliable EV charging solution should account for vehicle fleet growth over a period of at least 5–10 years. Project developers can install a limited number of units in the initial phase while reserving space and capacity for cable trenches, distribution cabinets, communication lines, and additional parking bays.

Modular design helps minimize maintenance time. If a power module malfunctions, maintenance personnel can quickly locate and replace the component, thereby reducing the risk of prolonged system downtime.

VII. EV Charger Selection: Conclusions and FAQs

Quick Matching Table: Scenarios vs. Door Energy Products

Ultimately, selecting the right equipment is not about choosing the highest power rating, but finding the optimal combination that aligns with the vehicles, site conditions, grid capacity, and operational goals.

For long-duration parking scenarios, the Door Energy W Series enables coverage of more parking bays while placing less strain on the power distribution system. Commercial projects can establish a tiered charging system using the C Series (20–40 kW) and D Series (60–160 kW). Projects involving highways, public transit, logistics, and heavy-duty trucks require further evaluation of the U Series and H Series, particularly regarding their dynamic power allocation capabilities when charging multiple vehicles simultaneously.

Before project initiation, Door Energy can conduct a needs analysis based on vehicle specifications, parking duration, average daily energy consumption, connector standards, and grid capacity. This data-driven approach allows enterprises to minimize the risk of over-provisioning while retaining scalability for future fleet expansion.

FAQ

Q1: How do I decide between a Door Energy AC EV Charger and a Door Energy DC Fast Charger?

A1: The choice depends primarily on parking duration. For vehicles parked for 4 hours or more, 7–22kW AC units are usually more cost-effective; for parking durations of 1–3 hours, the 20–40kW C Series is a suitable option; if a vehicle needs a significant charge within 30–60 minutes, the 60–160kW D Series is the better choice.

Q2: Does higher power output guarantee faster charging?

A2: Not necessarily. Actual charging speed is limited by the vehicle's maximum charging power, battery State of Charge (SOC), temperature, and charging curve. If a vehicle can only accept 100kW, the actual output will be capped by the vehicle's limitations, even when connected to a 160kW charger.

Q3: What are the power ratings for the Door Energy C Series and D Series?

A3: The Door Energy C Series offers 20kW, 30kW, and 40kW options; the D Series offers 60kW, 80kW, 120kW, and 160kW options. The C Series is suitable for medium-speed DC charging, while the D Series is better suited for commercial and public fast-charging applications.

Q4: How many charging ports should be installed at a public charging station?

A4: The number should be calculated based on the average daily number of visiting vehicles, average charging time, and operating hours. A basic formula is: Number of ports ≈ (Number of vehicles during peak periods × Average occupancy time) ÷ Duration of peak period. It is also recommended to include a 10%–20% capacity buffer.

Q5: Why do charging stations need OCPP?

A5: OCPP enables chargers to connect to third-party or proprietary management platforms, facilitating remote monitoring, user authorization, tariff setting, transaction recording, status checking, and fault diagnosis. For projects involving multiple chargers, these features significantly reduce management complexity.

Q6: Do hotels and shopping malls require DC Fast Chargers?

A6: Not necessarily. Hotel guests often stay for several hours or overnight, so AC chargers can meet most needs. Vehicle dwell times at shopping malls vary widely, making a mixed configuration of AC and DC chargers more suitable.

Q7: How do I calculate the total power requirement for an electric bus or logistics fleet?

A7: First, calculate the total daily energy consumption of the vehicles, then divide this by the available charging time and system efficiency. Next, factor in the number of vehicles charging simultaneously, the maximum charging power of the vehicles, and the dispatch schedule to determine the peak power requirements and the number of charging connectors needed.

Q8: What is the difference between the Door Energy H Series flexible charging station and standalone charging piles?

A8: The Door Energy H Series utilizes a centralized main cabinet connected to multiple charging terminals, allowing for dynamic power allocation. Compared to installing high-power equipment at every parking space, this approach is better suited for sites accommodating multiple vehicles and vehicle types with varying departure times.

Q9: What protection parameters should be considered for outdoor installations?

A9:Key factors to check include the IP ingress protection rating, IK impact resistance rating, operating temperature, humidity, altitude, and cooling method. Additionally, drainage, collision protection, shading, foundation construction, and cable management are equally important.

Q10: How much expansion capacity should be reserved when planning an EV charging solution?

A10: Designs can be based on vehicle growth projections for the next 3–5 years. It is generally recommended to reserve space for power distribution cabinets, cable conduits, communication lines, and additional installation sites, while using phased deployment to reduce initial investment costs.

Q11: Should highway service areas choose the Door Energy D Series or the U Series?

A11: If the site primarily serves standard passenger vehicles, the 120–160kW D Series covers a wide range of models. However, if there is high traffic volume, shorter dwell times, or a need to serve high-power passenger vehicles, buses, and logistics vehicles, the 180–400kW U Series should be considered.

Q12: How can one avoid high initial investment in charging stations that suffer from low utilization rates?

A12: It is advisable to analyze actual parking data, vehicle charging capabilities, and peak concurrency rates before deciding on the number of units. Additionally, employing a mix of power ratings, dynamic load management, and phased capacity expansion can help avoid the excessive upfront installation of high-power equipment.