Should your site choose 50 kW or 150 kW rapid chargers?

Choose rapid charging power around the energy drivers need during their visit and your site's connection. A 150 kW label does not mean every car receives that power: charging is limited by vehicle capability [S1]. Compare the complete project, including grid work and operating costs, then test whether faster turnover supports the extra investment. Checked October 2026.

Last checked 16 October 2026

How fast do 50 kW and 150 kW chargers charge a vehicle?

Rapid DC charging supplies direct current for the vehicle battery. A kilowatt (kW) measures power; a kilowatt-hour (kWh) measures energy. Higher available power can shorten the charging session, but the car must be able to accept it. Energy Saving Trust explains that vehicle capability can limit the delivered rate [S1].

For an assumed 25 kWh top-up at constant output, time = energy ÷ power. These are ideal arithmetic results, excluding losses, connection time, tapering and interruptions. They are not measured vehicle performance.

Do not promise a visit duration using that table. Request expected session times for relevant cars and arrival conditions. Ask for the average power across a session, not just a brief peak. For customers staying longer, compare destination and en-route charging before selecting rapid units.

Why can actual power be lower than the charger label?

The vehicle’s charging capability is a ceiling, and the energy needed depends on the battery and its starting charge. Charging speed can reduce as the battery fills [S1]. A faster cabinet therefore needs an appropriate vehicle mix and enough connection capacity to offer a useful advantage.

Ask for an output schedule covering the proposed equipment when neighbouring connectors are in use. Have the installer state whether its advertised power is per vehicle, per cabinet or shared across the installation. Request the same explanation for any grid limit or battery-supported design. Write the available service into your tender so that power-sharing assumptions are visible before you compare prices.

For a pub or farm shop, collect normal dwell time and busy periods. For a depot, record each vehicle’s energy requirement and departure deadline. These give the designer a service to deliver; a larger number on the cabinet does not supply that operating brief.

Check connector compatibility as well as power. The council charging guide describes CCS and CHAdeMO DC connections [S5]. Ask which of your intended vehicles each proposed outlet can serve.

What grid connection does your rapid charging site need?

A distribution network operator (DNO) manages the local electricity network. Government guidance recommends early discussion for workplace and depot projects with multiple chargers [S2]. Submit the total site demand and charging schedule, rather than a charger photograph.

As an assumed output-only comparison, two 50 kW chargers total 100 kW while two 150 kW chargers total 300 kW. Neither is the complete import requirement: ask the designer to include equipment losses, auxiliary loads, other business demand and the intended simultaneous operation.

Request separate prices for the electrical connection, on-site equipment, cable routes, civil work and ongoing capacity costs. Ask what remains payable if permission or access prevents construction. Use the DNO process guide and rapid charger cost guide to prepare the specification.

What could each size earn under the three funding models?

This is an illustration, not a quote. Every input is an assumption. Capital ranges are sensitivity inputs, not verified market prices. The example holds energy sold constant to avoid assuming that faster hardware creates demand. It excludes tax, finance, grants, land rent, rates, payment fees and replacement reserves.

Annual energy E = sessions × 365 × 25. Sales = E × £0.70. Electricity cost = E × 1.10 × £0.25. Surplus N = sales − electricity − annual software and maintenance. Mid-use sales are £31,937.50; electricity is £12,546.875. N is £17,390.625 for 50 kW and £16,390.625 for 150 kW.

Fully funded income = sales × 5%. Part funded annual net is half the relevant self funded net: approximately £2,878 / £8,695 / £18,391 for 50 kW and £2,378 / £8,195 / £17,891 for 150 kW. Simple return on investment (ROI) = annual net ÷ host capital × 100; payback = host capital ÷ annual net. Using unrounded results, part funded and self funded have matching ranges here because both capital and net are halved in part funded.

The comparison asks whether extra completed sessions justify extra capital. Model that uplift only after reviewing traffic, competition, vehicle capability and parking turnover. Long payback may exceed the useful equipment or agreement period; simple payback does not allow for replacement spending.

What public charging duties and contract questions matter?

The regulations distinguish workplace-only access from public use and exempt micro businesses from specified operator duties. Check the operator’s status, not only the host’s size [S3]. In-scope paid rapid installations need contactless payment and a free staffed helpline available around the clock [S4].

Ask your solicitor to review lease length, parking control, liability, assignment, removal and exit terms. Request written responsibility for power bills, maintenance, driver support and rates. Compare those terms alongside the funding options.

What should you do next?

Send your site plan, dwell-time evidence and available supply information. Get matched with an installer that covers your area for a scoped proposal.

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