Electric Charging Solutions for Vehicle Fleets: A Guide to Depot and Overnight Charging

When a company's service vehicles, sales fleet, delivery vans or staff cars go electric, the most critical question is no longer 'which vehicle should we buy' but 'where, when and how will we charge these vehicles'. Fleet charging is a very different engineering problem from a single home's wall-mounted device: because in the same facility multiple vehicles want to charge by sharing a limited amount of electrical power, often during the same hours.

This guide explains step by step why AC charging done at the depot and overnight is the backbone of the fleet, when DC top-up during the day comes into play, how many devices and how much power you will need (sizing), why load management becomes mandatory in a multi-vehicle facility, and how per-driver/per-vehicle authorisation and reporting are set up over OCPP.

Why is fleet charging different from home charging?

At home there is a single vehicle, it stays plugged in all night, and there is plenty of time until morning. With a fleet the picture changes: the number of vehicles rises, everyone's parking window is different, some vehicles are out in the field during the day, and the electrical connection's power may not be able to feed all devices at full power at once.

That is why three headings stand out in fleet charging: (1) the right device type and count, (2) smart sharing of the total site power, (3) measuring how much energy each vehicle/driver consumes. Unless all three are solved together, the fleet transition will not be sustainable.

Depot and overnight charging: AC, the backbone of the fleet

Fleet vehicles mostly sit parked at the facility, depot or car park at night. This is the longest and cheapest charging window. Because vehicles can stay plugged in for 8-12 hours, high power is not needed; AC wallbox devices are at the very centre of this scenario.

In AC charging, the conversion is done by the onboard charger (the in-vehicle charging unit); the station delivers the grid's alternating current to the vehicle, and the vehicle converts it into the direct current suitable for its battery. For this reason AC devices are simpler, more economical and well suited to being rolled out across many parking spaces.

The Bemis E-V Charge AC wallbox family offers Type 2 socket models in the 7.4-22 kW power range; Type 2 is the standard AC charging socket in Türkiye and Europe. This slow but uninterrupted overnight charging is the most reliable and most cost-effective way to ensure the fleet sets off fully charged every morning.

The basic rule of fleet electrification is simple: design your vehicles to be charged cheaply and quietly overnight, not fast during the day.

DC top-up during the day: when is it needed?

Not every fleet fits within the night. In operations that work in shifts, cover high mileage during the day, have short intervals between depot returns, or where vehicles are used around the clock in rotation, fast top-up during the day is needed. This is where CCS2 DC fast charging comes in.

In DC charging the conversion is done not in the vehicle but in the station; this means high-power direct current is delivered directly to the vehicle and charging time is shortened significantly. CCS2 is the standard DC fast-charging socket in Türkiye and Europe. Bemis E-V Charge CCS2 DC units are used to give the vehicle a fast 'energy top-up' during short windows such as breaks or delivery intervals.

The practical setup is usually a hybrid: many AC wallboxes cover the night, while a small number of CCS2 DC units handle urgent/critical top-up during the day. This keeps both the investment balanced and operational flexibility preserved.

Device count and power planning (sizing)

Choosing the right number of devices is the most critical step of a fleet project. Too few devices means queues and vehicles that do not get charged; more power than needed means unnecessary infrastructure cost. When planning, the following questions must be answered:

• How many vehicles are in the fleet and how many kilometres do they cover on average per day?
• What is the vehicles' parking window at the facility (how many hours can they stay plugged in overnight)?
• Do they all return at the same time, or is it shift-based/spread out?
• How much power is the facility's electrical connection suitable to draw (existing transformer/panel capacity)?
• What is the vehicles' onboard charger power (for example, does it accept single-phase or three-phase)?
• Will the fleet grow in the near future (need for scalability)?

The basic distinction here is between kW (power, that is charging speed) and kWh (energy, that is the total amount transferred to the vehicle). You calculate 'how much energy' (kWh) a vehicle needs overnight from its daily kilometres, divide it by the number of hours in the parking window, and find the required 'power' (kW). For most fleets, low-power but numerous AC points are more efficient than a few high-power points.

Parking-window logic

If a vehicle is going to stay plugged in for 10 hours overnight, trying to charge it in 1 hour is unnecessary. Spreading the energy over a wide time span makes it possible both to work with lower-power (and therefore more economical) devices and to share the facility's total power among more vehicles. In fleet planning, the rule 'the longer the window, the lower the required power' is decisive.

Why is load management mandatory in a multi-vehicle facility?

Suppose a facility has 10 units of 22 kW AC devices. If they all run at full power at the same time, an instantaneous demand of 220 kW arises; yet the facility's connection may not be able to handle it. This is where load management (load balancing / dynamic power sharing) comes in.

Load management intelligently distributes the available total power among the vehicles connected at that moment. If few vehicles are plugged in, it gives each of them more power; if many vehicles are charging at once, it divides the power fairly and does not overload the facility's main fuse/transformer. This way you can install more devices without an expensive connection increase or transformer investment.

• Static sharing: total power is divided among the devices in fixed proportions.
• Dynamic sharing: the power remaining for charging is distributed in real time according to the facility's instantaneous consumption.
• Prioritisation: priority can be given to critical vehicles (for example a service vehicle leaving early in the morning).

Load management is not a 'luxury' in a fleet setup but a practical necessity; because a facility's power is usually lower than the total rated power of all the devices.

Per-driver and per-vehicle authorisation: RFID and OCPP

In a fleet, the answer to 'who charged, with which vehicle, and how much' is critical both operationally and financially. Two concepts stand out here: authorisation (who can start charging) and reporting (how much energy was consumed).

RFID cards assign an identity to each driver or vehicle; charging does not start until the card is read at the device. This both prevents unauthorised use and ties each charging session to a specific user. OCPP (Open Charge Point Protocol), on the other hand, is the open protocol that lets the devices talk to a central management software (CSMS).

Bemis E-V Charge's OCPP-compatible models enable remote monitoring and smart management: you can see the devices from a single panel, report on sessions, manage user permissions, and break down energy consumption by vehicle or driver. For a deeper understanding of OCPP, you can take a look at our related guide.

The visibility reporting adds to a fleet

• A monthly breakdown of kWh consumed for each vehicle/driver
• Cost allocation and expensing by department/branch
• Charging-point utilisation intensity (for capacity planning)
• Detection of faulty or unused devices
• Forecasting additional devices that will be needed as the fleet grows

Scalability: 5 vehicles today, 50 tomorrow

Fleet electrification is rarely completed in one go; most companies transition gradually. For this reason, designing the infrastructure to be future-ready at the first installation saves money and time. When the panel, cabling and power allocation are planned from the start with growth in mind, adding new devices becomes far easier and cheaper.

OCPP-compatible devices are advantageous in this respect too: newly added stations are included in the same central management system, so there is no separate management hassle. Thanks to load management, the existing power is also re-shared across the increased number of devices.

A total cost of ownership (TCO) perspective

When evaluating a fleet charging investment, you should look not only at the device price but at the total cost of ownership. In this approach, the installation cost is considered not on its own but together with the value it will create over its operating life.

• Device and installation (hardware + electrical infrastructure)
• Operation: optimising the energy bill by charging during low-cost windows such as the night tariff
• Saving on infrastructure cost by avoiding a connection/transformer investment thanks to load management
• Using reporting to allocate costs to the right place and to see waste
• Making future device additions cheaper thanks to scalable infrastructure

With the right setup, fleet charging becomes an investment that offsets the initial cost over time with low energy expenditure and operational efficiency. (Because the exact savings and payback period will vary according to the electricity tariff, number of vehicles, usage profile and relevant regulations, they should be calculated specifically for the facility.)

An equipment family suited to fleets

In a fleet project, it is not a single product but an equipment family that works together: many AC wallboxes for overnight charging, CCS2 DC units for daytime top-up, the right Type 2 charging cables for the vehicle connection, and OCPP-compatible models for remote management. Bemis E-V Charge offers all of these components under one roof with domestic manufacturing.

The choice of Type 2 cable also matters in a fleet; a cable suited to the vehicles' onboard charger power (single-phase/three-phase, 16A/32A) directly affects charging speed and safety. For corporate fleet projects, our B2B process, which handles planning, sizing and device supply together, comes into play at this point.

Summary: a checklist for fleet charging

• Plenty of AC wallboxes for overnight/depot charging; a small number of CCS2 DC units for critical daytime top-up.
• Size the number of devices according to vehicle count, daily km and parking window (sizing).
• Plan load management (dynamic power sharing) from the start so as not to strain the facility's power.
• Set up authorisation and per-driver/per-vehicle reporting with RFID + OCPP.
• Design the infrastructure to be scalable for future growth.
• Evaluate the investment by total cost of ownership, not by device price.

A company that sets up these six items correctly from the outset can transition its fleet to electric in a smooth, scalable and cost-sustainable way.