Why the Official Figure Is Only a Starting Point

Every new electric car sold in the UK quotes a range figure produced under a standard laboratory procedure known as WLTP. It is a genuinely useful test: it is repeatable, it is the same for every manufacturer, and it lets you compare one model against another fairly. What it is not, however, is a prediction of your Tuesday morning drive to work.

The test takes place on a rolling road in a temperature-controlled cell. The speed profile is prescribed, the acceleration gentle, the climate control restricted, and there are no passengers, no shopping in the boot and no roof bars. Tyres are at ideal pressures and the battery starts in optimum condition. Real life rarely obliges on all counts at once, which is why the number on the screen and the number in the brochure can differ by a third or more.

Speed Is the Single Biggest Factor

Aerodynamic drag rises with the square of your speed, so the energy required to push through the air climbs steeply as you press on. A typical electric car might use half again as much energy per mile at 70 mph as it does at 40 mph. That is not a quirk of electric cars — it applies to petrol and diesel too — but it is more noticeable when your "fuel tank" is a battery you have to recharge.

• Town driving: at 25-35 mph, with gentle stop-start and regenerative braking recovering energy, many EVs beat their official figure.
• A steady 50-60 mph: this is where most cars land closest to the published range.
• Motorway speeds of 70 mph and above: expect 15-25% less range than the label suggests, and more in wind or rain.

A practical habit worth adopting: on a long journey, easing off from 70 to 65 mph costs you only a few minutes over a hundred miles but can add a comfortable margin of range.

What Cold Weather Really Does

Lithium-ion batteries are happiest at around 20-25°C. Below roughly 10°C the chemistry slows, internal resistance rises, and the pack both accepts and delivers energy less readily. On top of that, you are heating a cabin rather than using waste engine heat, as a combustion car does. Cabin heating can draw 2-4 kW, which over an hour is the equivalent of a good few miles of driving. A heat pump softens this considerably; a simple resistive heater does not.

In a British winter, a 15-30% range reduction is entirely normal, and very short urban trips in freezing conditions can be worse still because the battery never warms through. Summer motorway driving with the air conditioning on typically costs only 5-10%.

• Precondition the cabin and battery while still plugged in, so the grid pays for the warm-up rather than your battery.
• Lean on seat and steering wheel heating, which warms you directly for far less energy than heating the whole cabin.
• Defrost and demist while connected, not on the move.
• Park in a garage or under cover where you can — even a few degrees helps.

Weight, Roof Boxes and What You Are Carrying

Every extra 100 kg costs roughly 2-5% of range, so four adults and a full boot genuinely register. Roof bars and roof boxes are worse still, because they attack the one thing that hurts most: aerodynamics. A loaded roof box at motorway speed can knock 10-20% off your range, and the effect is worse in a headwind.

Towing is in a category of its own. A caravan or trailer can halve your range, so plan realistically on 50% of your normal figure and route accordingly. Tyre pressures matter too — under-inflated tyres increase rolling resistance and can cost a couple of percent on their own, so check them monthly, and more often in cold snaps.

Driving Style and Regeneration

Smooth really is fast in an electric car. Anticipating traffic, lifting off early and letting regenerative braking do the slowing means energy flows back into the battery instead of disappearing as heat from the friction brakes. Harsh acceleration followed by hard braking throws that opportunity away.

Eco modes dull the throttle response, which sounds dull but genuinely helps. One-pedal driving, where lifting off slows the car noticeably, encourages exactly the behaviour that saves energy once you are used to it. Cruise control is efficient on flat motorways but can be wasteful on rolling hills, where it brakes downhill and accelerates uphill rather than letting momentum work for you.

Reading Your Own Numbers and Planning with Confidence

The most useful figure you can learn is your car's miles per kWh — the electric equivalent of miles per gallon. A mid-sized EV might return 3.5-4.5 miles per kWh in mild weather and 2.5-3.2 in the depths of winter. Multiply that by your battery's usable capacity and you have a far more honest range estimate than anything in the brochure.

Trip computers and predicted-range displays recalculate constantly, and they get more trustworthy the longer you have been driving in similar conditions. After twenty minutes at a steady motorway speed in the cold, the car's own estimate is usually better than your mental arithmetic.

For everyday use, though, most drivers cover 20-30 miles a day and charge at home overnight, where range simply never becomes a consideration. For longer trips, the winning approach is to plan one sensible charging stop, arrive with a buffer, and remember that fast charging is quickest between roughly 10% and 80%. Warm the car while plugged in, drive a little more gently, carry less, keep the tyres right — those small habits add up to a real-world range that matches the paperwork far more often than you might expect.