Charging at home off-peak (7p/kWh) costs around 2p per mile. Petrol at 145p/litre and 45mpg is around 14p per mile. Public rapid charging at 70p/kWh costs around 20p per mile — sometimes more than petrol.
EV running costs only make sense if you understand which charger you're using. Here are the real UK numbers.
Home, off-peak (the best case)
A 7p/kWh EV tariff (Octopus Go, Intelligent Octopus, EDF GoElectric) charging a 60kWh battery for 240 miles costs £4.20. That's 1.75p per mile — eight times cheaper than petrol.
Home, standard rate
At 27p/kWh (the typical UK cap), the same 240-mile fill costs £16.20 — about 6.75p per mile. Still half the cost of petrol.
Public rapid (the worst case)
BP Pulse, Instavolt, Ionity at 79–85p/kWh: a 240-mile charge costs £47–£51 — that's 19–21p per mile. Comparable to or worse than a 50mpg diesel.
The honest answer
EVs save money if you charge at home overnight on an off-peak tariff. If you rely on public rapid chargers, the saving disappears. Always do the home-charger sums before buying.
Is a 7kW home charger worth it? — Yes, if you do 8,000+ miles a year. Payback is typically 2–3 years on the kit, and it unlocks the cheap overnight tariffs.
Why are public chargers so expensive? — They pay business-rate electricity, fund the hardware, and absorb 20% VAT (home charging is 5%). Politicians keep promising to fix the VAT — nothing yet.
More detail on: How much does it cost to charge an EV in the UK vs petrol?
The short answer above covers the usual case. Below is the extra detail a UK driver normally needs to act on it — how to narrow the fault down, what it should cost, and when it is worth paying a garage rather than carrying on. This is general guidance from a working mechanic, not a substitute for someone putting your own car on a ramp.
What a fair UK price looks like
Independent labour rates in Scotland and the north of England typically run £45–£75 an hour; main dealers routinely charge £110–£160. On most repairs the parts are the smaller half of the bill, so the labour rate and the book time decide what you pay. Ask for the quote split into parts and labour, ask whether the parts are OE, OE-equivalent (Bosch, Denso, Delphi, Ferodo, Pagid) or budget, and ask what the warranty is on the work. A garage that will not break a quote down is a garage to walk away from.
When a second opinion pays for itself
Any quote over about £400 is worth a second look, and any quote that involves replacing a component nobody has actually tested is worth challenging. Ask what test proved the part is faulty. On sensors and modules in particular, live data or a substitution test should come before a parts bill. It is entirely reasonable to say: show me the reading that tells you this is the fault.
Safe to keep driving?
Treat anything affecting brakes, steering, tyres, seat belts or visibility as stop-now, no matter how well the car appears to be driving. Overheating and low oil pressure are also stop-now: the damage curve on both is measured in minutes, not miles. Most other faults will let you drive gently to a garage, but if the car is in limp mode, losing fluid, or the fault changes how it steers or stops, get it recovered instead. Recovery is cheaper than a tow plus a new engine.
What Bob would check first
Start with the cheap, common and visible: fluid levels and their condition, tyre pressures and wear pattern, battery voltage and terminal condition, and every connector and vacuum pipe in the area of the fault. A surprising share of electrical gremlins are a corroded earth or a chafed loom, and a surprising share of running faults are an air leak downstream of the sensor doing the complaining. Only after that does anything get unbolted.
When it is worth going to a main dealer
Three situations justify main-dealer money: an open safety recall (free), a live manufacturer warranty or goodwill claim, and coding or programming work that needs manufacturer-level software. Everything else — servicing, brakes, suspension, clutches, cambelts, diagnostics — an experienced independent will do to the same standard for a good deal less, and using an independent does not invalidate your warranty under UK block exemption rules as long as the correct parts and schedule are used.
Get an answer on your own car
If you want this looked at properly for your exact vehicle, send the details and Bob will write back — make, model, engine, mileage, when the fault happens and any codes you have. You get a written reply from a qualified UK mechanic with 32 years on the tools, not a chatbot, and your money back if he cannot help.
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