EV Charging Explained

Charger speeds: what the numbers actually mean

EV charging is measured in kilowatts (kW). The key is matching the charger speed to how long your customers stay — not buying the fastest or cheapest option.

Charger type	Power	Time to charge 20–80% *	Dwell needed	Best for
🔌 3-pin plug	2.3kW	26+ hours	—	✕ Not recommended — see section below
🌙 Slow AC	7.4kW	5–7 hours	Overnight	Hotels, B&Bs, holiday parks
☀ Fast AC	22kW	~2 hours	Half day	Workplaces, restaurants
⚡ Rapid DC	50kW	~45 mins	Short stop	Roadside, retail parks
🚀 Ultra-rapid DC	150kW+	~15 mins	En route	Motorway services only

* Typical charge time from 20–80% state of charge on a 60kWh battery. Actual times vary by vehicle model, battery temperature and the vehicle’s own onboard charger limit. Most EVs cap AC charging at 7.4kW or 11kW regardless of charger output. Above 80%, battery charging slows significantly to protect battery health — this is called the charging curve.

For most small businesses, 7.4kW AC is the right starting point. It handles overnight stays completely, costs £1,000–£2,000 installed after grants, works on single-phase electricity, and delivers a full battery by morning. See the DC rapid charging guide if you have high footfall and short dwell times.

Why not just use a 3-pin plug?

The most common question from B&B and hotel owners. The answer covers fire safety, legal compliance, insurance and guest experience.

Fire risk: A 3-pin socket runs near its maximum 13A rating continuously for 8–10 hours. On older commercial wiring this is a genuine overheating and fire risk.
No safety cutoff: Many older commercial properties lack RCD protection on outdoor circuits. Without it, a fault in the charging cable has no automatic safety cutoff.
Legal position: The IET Code of Practice states 3-pin charging is acceptable for temporary use only. Regular business use requires a dedicated circuit with RCD protection, compliant with BS 7671.
Insurance: Commercial property insurers are increasingly asking about EV charging arrangements. An unmonitored 3-pin socket in a guest car park is a grey area that may affect your cover.
No metering: A 3-pin socket cannot measure how much electricity a guest uses. You cannot charge guests for usage, and bear the full cost yourself.
Insufficient speed: 2.3kW adds ~8 miles of range per hour. A guest arriving with 40 miles of range may not have enough charge to leave by morning.

Bottom line: A dedicated smart charger installed by an OZEV-approved electrician costs as little as £1,000 net of grants, is fully insurable, lets you meter and charge for electricity, and gives guests a full battery overnight. The 3-pin socket saves nothing and risks everything.

The Ofgem rules on charging guests for electricity

This is the rule most hospitality operators don’t know about — and one you can inadvertently break.

Ofgem Maximum Resale Price

Under Ofgem’s Maximum Resale Price rules, anyone reselling electricity to overnight guests cannot charge a higher unit rate than they pay their own supplier.

The typical commercial electricity rate is 27–30p/kWh as of 2026. You can add a reasonable service fee on top — but you cannot simply multiply your rate by three and call it a charging fee.

The good news: Ofgem’s 2014 decision confirmed that the MRP does not apply to electricity sold from dedicated EV charge points. A properly installed, metered EV charger gives you genuine pricing flexibility — pricing at or near your actual cost per kWh with a transparent service fee is the safest approach and likely to remain compliant under any forthcoming rule changes.

A 3-pin socket, by contrast, cannot meter usage — you either give electricity away for free or have no way to charge fairly.

The 8kW payment regulation — what it means for AC charging

The Public Charge Point Regulations 2023 require contactless payment on public chargers above 8kW. Here’s how this applies to the most common business charger speeds.

7.4kW AC — below the 8kW threshold

A 7.4kW charger falls below the 8kW contactless payment threshold. You are not legally required to offer contactless payment. However, you will still need a smart charger with RFID or app-based metering if you want to charge guests per kWh. This is the right setup for most hotels, B&Bs and holiday parks.

22kW AC — above the 8kW threshold

If your 22kW charger is publicly accessible — listed on Zapmap or open to non-guests — contactless payment (debit/credit card) is mandatory from November 2024. Penalty: up to £10,000 per charger for non-compliance. Pricing must be displayed in pence per kWh.

If access is restricted to guests or employees only via RFID or a gate, the public charger regulations may not apply. Confirm with your installer before installation.

22kW AC requires three-phase electricity

This is the most important practical point. A standard UK property has single-phase electricity, which limits AC charging to a maximum of 7.4kW. To install a 22kW fast charger you need a three-phase supply — or a supply upgrade from your DNO, which typically costs £3,000–£10,000 and can take 6–12 weeks to arrange.

For most small hospitality businesses, 7.4kW AC on single-phase is the practical and cost-effective choice. 22kW makes sense for workplaces with high EV staff usage or restaurants with 2–4 hour dwell times where you already have three-phase supply.

Recovering your installation costs over time

A 7.4kW smart charger is not just a cost — it’s an asset. Here’s how the numbers work for a typical B&B or hotel.

Example: rural B&B, 1 unit, 7.4kW smart charger

Installed cost: ~£1,200 net after £500 Workplace Charging Scheme grant
Electricity cost: 28p/kWh (typical commercial rate)
Guest charge rate: 38p/kWh + £1.50 session fee
Typical session: 30kWh (arriving at 40%, leaving at 90%)
Revenue per session: £11.40 + £1.50 = £12.90
Electricity cost per session: £8.40
Net margin per session: ~£4.50
Payback at 3 sessions/week: ~18 months

After payback the charger generates ongoing income — and the competitive advantage of being EV-accessible continues to grow in value as adoption increases.

For DC rapid charging revenue models and CPO partnership arrangements, see the DC rapid charging guide.

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