How do you size depot charging for a fleet of electric vans?

Size depot charging from route energy and time parked, then test each van against its next departure. The 2021 smart charge point regulations cover eligible private workplace equipment sold in Great Britain [S1]. Smart controls help schedule demand, but your design also needs sufficient power, usable bays and a plan for faults. Checked October 2026.

Last checked 16 October 2026

How much energy does each van need before its next shift?

Begin with route records, not the fleet’s total battery capacity. Record distance, payload, return time, next departure and energy used. Include unusual duties and vans that park away from base. Government research describes varied driving and charging patterns and practical barriers, so a single fleet-wide average is a weak starting point [S3]. For a yard or trade counter, use the trade premises van charging guide to plan the overnight routine.

Define the units in your worksheet. A kilowatt, or kW, measures charging power. A kilowatt-hour, or kWh, measures energy. For an initial calculation, multiply miles by measured kWh per mile, then allow for charging losses. Use trial data for your van, route and load rather than borrowing a passenger-car figure.

Keep the energy needed for the next duty separate from the wish to fill every battery. Ask operations to specify a departure target and reserve. Read the fleet roadmap before fixing the equipment order so vehicle procurement and depot work use the same timetable.

How much depot power does an overnight van fleet need?

Here is an illustration, not an equipment specification. Assume 12 vans, each travelling 80 miles a day at 0.4 kWh per mile delivered from the battery. Assume 90% charging efficiency and a common 10-hour charging window. These are chosen inputs, not market averages.

The distinction matters: nominal charger power and the minimum average required over the window are different calculations. The example assumes constant access throughout the window. It does not include a late return, equipment outage or the building’s demand.

Ask your distribution network operator, or DNO, and electrical designer to assess the resulting demand profile. UK Power Networks’ Optimise Prime work examines commercial-vehicle load profiles and flexibility [S2]. Use the DNO application guide to prepare the information.

How many chargers and connectors does your depot need?

Count accessible connections separately from power. In the illustration, a van needing 35.56 kWh at a constant 7 kW requires about 5.08 hours. Sharing that output between two identical vans needs about 10.16 hours before allowing for movement. It does not fit the assumed 10-hour window.

That arithmetic rules out a simplistic sharing plan for this example. It does not establish a universal connector ratio. Ask the designer to model each arrival, cable connection and departure. A shared-power system may serve many connected vans without every connector receiving its nominal maximum simultaneously.

Check the vehicle’s charging capability. Energy Saving Trust explains that the car or van limits the charging power accepted, even where the point can offer more [S4]. Compare AC charger ratings with the exact vehicle variant, then assess whether faster equipment changes the dispatch outcome.

Can load management avoid a grid upgrade?

It is an option to assess, not a conclusion to assume. Ask for a model combining building demand and charging across the actual charging windows. UK Power Networks discusses flexible and profiled connections for commercial charging [S2]. Its profiled connection guidance describes capacity varying by an agreed schedule, with a contractual minimum [S5]. Availability and terms need a site-specific check.

In the illustration, a 50 kW charging allocation over the whole 10-hour window provides 500 kWh before any operating constraints. That exceeds the assumed fleet requirement, but only a timed model can show that each van receives its energy before departure.

Use the load management guide when preparing the control specification. Request a demonstration of priority vehicles, loss of communications, building-load changes and manual intervention. The smart charge point rules set device requirements for eligible equipment; they do not prove your dispatch schedule works [S1].

What happens when a van returns late or a charger fails?

Stress-test the plan before ordering. Suggested scenarios include a van returning with less energy than expected, a blocked bay, an early departure and a failed charging output. Record which duties still complete and which need another charging arrangement.

Ask the team to demonstrate alerts reaching someone who can act. An alert arriving after the dispatcher leaves is not a complete response procedure. Assign responsibility for checking plugged-in status and resolving a failed session before the next shift.

For public backup, try the route and parking space with the intended van. The official research records charging queues and vehicle-fit concerns [S3]. Add staff time and access costs to the fleet ownership-cost comparison instead of assuming backup energy is the only expense.

The public charging regulations exclude defined workplace charging [S6]. If visitor charging is proposed, ask the operator to assess the access rules before treating the installation as a private depot throughout.

What should you do next?

Send installers an anonymised duty-cycle summary, site load information, parking plan and future fleet phases. Request a timed charging proposal, a priced scope and a demonstrated failure response. For leases, planning, access, liability and exit terms, identify the open questions before accepting the design and check contractual issues with your solicitor.

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