How many charging points does a company need? Size capacity and power for demand

The right number of charging points depends on the vehicles that actually need to charge at the same time, the energy they require and the parking time available. A ratio such as “one charging point for every three EVs” is not enough to justify an investment. Plan parking spaces and electricity supply separately: many vehicles can be connected simultaneously while sharing a limited total power supply. Conversely, ample connection capacity is of little use if too few accessible charging spaces are available.

Start with an operating day, not the number of parking spaces

An employee survey about planned EV purchases is helpful, but does not yet describe charging demand. Also record how often those people are on site, where their vehicles charge elsewhere and how much energy they actually need during their stay. Distinguish a dedicated company car that has to visit customers in the morning from a private commuter car with charging available at home.

Choose several typical days. A Tuesday with high office attendance may require more connections than the weekly average. In shift-based operations, handovers may cause the decisive peak. Seasonally high consumption combined with a busy site should also be considered. The existing guide to a charging strategy combining home, workplace and public charging helps classify the vehicle groups in advance.

These five data points determine the initial design

Create a table for each vehicle group. Personal names are normally unnecessary for preliminary technical planning; groups and traceable vehicle references are sufficient.

Plan using the vehicles' actual configurations. A more powerful AC charger does not increase charging power if the car's onboard charger can accept less. The AC/DC/HPC charging guideexplains the technical basics. Electrical sizing itself belongs in professional design; the technical guide from VDE and its partners covers vehicle demand, connection and power management for this purpose.

First calculate energy per time window

A hypothetical office site expects twelve vehicles, each needing to draw 18 kWh at the charging point. The 18 kWh is explicitly an assumed measured consumption quantity including the charging losses already allowed for in the example. Together, the vehicles require 216 kWh. Over six actually usable hours, this mathematically corresponds to 36 kW of average power.

This figure is not a connection commitment. It assumes all vehicles can use the time window, the control system distributes power appropriately and no additional constraints arise. Two vehicles departing earlier change the demand during the first few hours even though total daily energy remains the same. Calculate at least hour by hour, and at shorter intervals for tightly scheduled operations.

For each time window, the first check is that the energy required by that point must not exceed the energy that can realistically be delivered. If the total is sufficient but an early-departing vehicle fails to reach its target, prioritisation or equipment must change.

Make a deliberate decision about moving vehicles

Twelve vehicles cannot automatically be served by six charging points. This works only if switching between vehicles is planned, staff are available and the process is operationally reliable. Include connecting and manoeuvring time. Administration staff cannot spontaneously move a vehicle whose key is with a field sales employee.

Compare two options: more connections sharing power, or fewer connections with more frequent turnover. Assess walking time, interruptions, key management and potential conflicts between departments. Convenient occupancy is often more valuable operationally than a high calculated utilisation rate for each charging point. This must be decided for the specific site; it is not a general preference for one hardware option.

Also define which spaces remain reserved for business vehicles and which can be used flexibly. A visitor who unexpectedly stays for several hours must not block the last necessary connection for a pool vehicle.

Load management must solve the right problem

Static load management limits the charging area to an agreed value. Dynamic load management also takes account of the site's changing load, provided the necessary metering and controls are in place. Both can distribute power, but cannot compensate for missing energy or a charging window that is too short.

Do not therefore request a blanket simultaneity factor without justification. Ask for a traceable load scenario: Which vehicles charge simultaneously, which other loads are running and how much energy is available before departure? Different peaks may matter for an office with a heat pump, kitchen and workshop than for a parking-only site.

The response to a communication failure also belongs in the design. A safe, limited fallback power level may protect the site while still being insufficient for some departures. You should understand that distinction before ordering.

Expand according to demand and prepare costly routes early

Not every forecast vehicle purchase requires an operational charging point immediately. An expansion plan with triggers is sensible: for example, repeatedly missed charging targets, increasing waiting times or new binding vehicle orders. Document the expected timing and the responsible decision-maker.

Distinguish hardware that is easy to add from extensive building work. Cable routes, distribution boards, conduits and parking layouts should be planned so that expansion does not unnecessarily require fresh groundworks. At the same time, unused reserve capacity also costs money. Request separate quotes for the basic provision and a specific expansion phase.

A plan should therefore show three figures: charging points needed today, power required today and expansion capacity technically prepared for. These figures do not have to grow at the same rate.

Make the design subject to verifiable acceptance

Before purchasing, agree on a test day with representative occupancy and at least one demanding departure window. Check whether vehicles reach their agreed targets, the site limit is observed and operation works without unplanned assistance. Successful charging with only one test car does not demonstrate adequate provision for a fleet.

For workplace fleet charging infrastructure , StromNow describes planning based on parking times and vehicle needs with load management. For a site assessment , compile vehicle groups, typical presence, required kWh, connection data and planned fleet growth. This makes it possible to discuss a specific design that can later be measured against operational results.