How should visitor dwell time determine your charger speed?

Dwell time is how long a vehicle stays parked at your site. Choose charging power by dividing the energy visitors need by their available charging time. DfT groups charging at 150 kW and above with short stops whose main purpose is charging [S1]. Longer stays can support lower power, subject to vehicle limits and shared supply. Checked October 2026.

Last checked 16 October 2026

How does parking time affect the charger you should choose?

Dwell time means how long a vehicle stays parked at your site. For electric vehicle (EV) charging, measure how much of that visit is actually available for charging. Time spent queueing, finding the bay or starting a session does not help meet the driver’s energy requirement.

A kilowatt (kW) measures charging power. A kilowatt-hour (kWh) measures energy. The initial calculation is energy required divided by time available. This reverses Energy Saving Trust’s charging-time equation [S2]. It gives a required average rate, not an instruction to buy equipment with exactly that label.

The Department for Transport associates lower power bands with long stays, middle bands with destination visits, and the highest band with short stops made principally to charge [S1]. Your visitor’s purpose matters as much as your sector name. A hotel can have overnight guests, diners, conference visitors and staff with different needs.

See charging speeds explained for the equipment options and charging times for the limits of simple time estimates.

Which charger speeds should different businesses investigate?

The following visit lengths and energy requirements are assumptions for screening options, not measured sector averages. Suggested equipment is a starting point for assessment. Actual delivery depends on vehicle acceptance, shared power and the connection [S1], [S3].

Alternating current (AC) charging uses the vehicle’s on-board conversion equipment. Direct current (DC) charging converts electricity outside the car [S2]. Before treating the garden-centre example as a case for 22 kW AC, check whether your visitors’ vehicles can accept that power.

The table deliberately shows average power needed below some equipment ratings. Spare time and power matter: a rate that only just meets the arithmetic has no allowance for delays or reduced delivery. Ask the installer to state the performance assumptions behind its proposed equipment.

Follow the relevant hotel, pub and restaurant or retail sector guide to develop your own service brief.

How can you calculate the power your visitors need?

Here is an illustration, not a quote or a forecast. Assume a pub visitor wants 14 kWh and stays for two hours. The required average is 14 ÷ 2 = 7 kW. If an assumed half-hour is lost before charging starts, only 1.5 hours remain. The new requirement is 14 ÷ 1.5 = about 9.3 kW [S2].

Now assume the vehicle accepts only 7 kW AC. A 22 kW AC label does not remove that vehicle limit [S2]. At the assumed constant accepted rate, the shorter charging window delivers 7 × 1.5 = 10.5 kWh before losses. Your choices include a smaller advertised top-up, a longer stay or a different charging service.

Repeat the exercise with your shortest useful visits, not just the longest ones. Ask a sample of visitors how much charge they need and whether they would choose the site because charging is available. Treat those answers as planning inputs, rather than evidence of annual utilisation or income.

For overnight guests, record departure deadlines. For fleets, record the next duty’s energy requirement. The same total overnight energy can produce different designs if some vehicles leave much earlier than others.

How many charging bays should your site provide?

Start with overlapping visits. Count how many vehicles may need charging simultaneously and whether drivers can reasonably move them. Charger speed alone does not determine bay availability: DfT notes that vehicles occupying spaces without actively charging can reduce access [S1].

For an illustration, assume four guests arrive together, each needing 20 kWh over ten hours. Total energy needed is 4 × 20 = 80 kWh. The average charging requirement is 80 ÷ 10 = 8 kW before losses [S2]. That calculation does not mean a single socket serves all guests without someone moving the cable or vehicles.

Ask for a design that tests both the energy schedule and physical access. More sockets with shared power may suit the service better than a single faster outlet. Dynamic load management can adjust charging to other building demand; assess it against your departure requirements [S3]. Read dynamic load management before comparing proposals.

What else should be in your charger brief?

Describe who can use the bays and when. State whether you want overnight guests to leave cars connected, whether short-stay drivers should move after charging and who will explain the system at reception. Request clear payment and parking information before visitors commit to a session.

For paid public charging, government guidance requires contactless payment on new public points rated at 8 kW and above deployed after 24 November 2024, and on all public points rated at 50 kW and above [S4]. That is one reason to assess operating requirements alongside speed. Check the classification and proposed terms with your solicitor; see the public charging checklist.

Then compare commercial charger costs and funding models. Use the names fully funded, part funded and self funded when requesting offers. Ask who controls access, pays connection costs, handles faults and funds removal or changes to the parking layout. Have your solicitor review lease length, liability and exit terms.

This guide selects a service requirement. It does not predict earnings or payback. Return on investment (ROI) compares the return with the capital invested. Take your actual demand, prices, costs and contract terms into the ROI guide before deciding whether charging should be a paid amenity, a fleet service or an income project.

What should you do next?

Write down visitor groups, overlapping stays, energy needs and departure deadlines. Use that brief to get matched with an installer that covers your area.

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