Electric car battery care for longer life

Why a little battery care goes a long way

An electric car's battery does not wear out like a clutch or a set of brake pads. It fades, quietly and gradually, losing a fraction of its usable capacity with every charge and every spell of high temperature. That fade is not inevitable, though. How you charge, where you park and how you drive all nudge the rate of degradation up or down, and the difference over five years of West Country driving is bigger than most people expect.

A pack that has been treated sensibly can still hold well over 90 per cent of its original capacity at 100,000 miles, while one that has lived on rapid chargers and been left sitting at 100 per cent for days on end can dip below 80 per cent far sooner. That matters twice over: once for your range on a wet Tuesday in January, and again when you come to sell, because battery health is the first question any sensible buyer asks.

Live in the twenty to eighty per cent band

For everyday driving, the sweet spot is simple. Keep the charge somewhere between 20 per cent and 80 per cent, and treat the extremes as occasional rather than routine. Sitting at a full charge for hours puts pressure on the cells, and running close to empty stresses them from the other direction.

• Set your car's charge limit to 80 per cent at home and leave it there. It takes a moment in the settings menu and it will pay for itself many times over.
• Charge little and often rather than waiting for a big top-up. Plugging in overnight at 7kW is the gentlest option available to most drivers.
• If you are heading to Cornwall or the Cotswolds tomorrow, charge to 100 per cent the night before and set off reasonably early. What you want to avoid is a car that sits at full for three days between trips.
• Avoid dropping below 10 per cent as a matter of habit. Some cars also lose a little performance and regenerative braking in that zone, which is unhelpful on a steep lane.

If your car uses an older lithium iron phosphate chemistry, the advice is slightly different: those packs prefer a full charge to 100 per cent once a week or so to keep their internal calibration honest, then the usual 80 per cent routine in between. Your handbook will tell you which you have.

Treat rapid chargers as a tool, not a habit

Rapid charging is brilliant. It is also the hardest thing you can do to a battery on a regular basis, because pumping 100kW or more into a pack generates real heat, and heat is what ages cells. Using a rapid charger occasionally on a long journey is entirely fine. Relying on one three times a week because you have no home charging is where the wear creeps in.

A few practical habits help:

• Use rapid chargers for journeys, not for the weekly shop.
• If you can charge at home or at work on a 7kW or 22kW point, do that instead, even if it is slower.
• After a long motorway run in warm weather, the pack is already hot. If you have the choice, let it rest for a while or use a slower charger rather than hitting it with maximum power immediately.
• On very cold mornings, a rapid charger will accept power slowly anyway while the pack warms. Do not panic if the first ten minutes look sluggish.

Precondition in the cold and think about where you park

Cold is the West Country driver's quiet enemy. A frosty morning in Exeter, Bodmin or Salisbury Plain can knock 20 to 30 per cent off your range before you have gone anywhere, because a cold battery both gives up energy less willingly and accepts it more slowly.

The answer is preconditioning. Most modern electric cars let you schedule a departure time, or warm the car from an app while it is still plugged in. Doing this uses mains electricity rather than your stored charge, so you set off with a warm cabin, clear windows and a pack that is already at a sensible working temperature. Ten minutes of preconditioning on a January morning is worth far more than ten minutes of frantic scraper work.

Where you park matters too. A garage, a carport or a sheltered side of the house keeps the pack a few degrees warmer overnight. If you must leave the car outside in a hard frost, try not to leave it at a very low state of charge. Somewhere around 40 to 50 per cent is a comfortable place for a cold snap. And once you are moving, lean on the heated seats and steering wheel rather than the cabin heater; they use a fraction of the energy.

Hills, coast roads and long trips

The West Country is genuinely good news for electric driving in one respect: hills. Regenerative braking on a descent down Porlock Hill or off Dartmoor puts energy back into the pack rather than cooking your brake discs. Get used to one-pedal driving and you will find your range on a hilly route is often better than you feared.

There is a catch worth knowing. Regenerative braking is reduced when the battery is cold or already at 100 per cent. If you are setting off on a hilly day, charging to 80 per cent rather than full means the regen is available from the first mile instead of being wasted.

Along the coast, salt air does not harm the battery itself, but it does not do your charge port any favours. Give the port and the cable ends a wipe and a rinse now and then, particularly through the winter, and check the rubber seal is sitting properly. A damp, gritty charge port is a nuisance you can easily avoid.

Buying, owning and selling with battery health in mind

If you are buying used, ask for a battery health report showing the state of health, and check the remaining warranty; most manufacturers cover the pack for eight years or 100,000 miles to around 70 per cent capacity. A car that has been charged to 80 per cent most of its life and rapid charged rarely is a better long-term buy than one with fewer miles and a harder charging history.

While you own it, keep a simple record of your charging habits and any health checks. When the time comes to sell, that paperwork is worth real money. A private buyer or dealer faced with two similar cars will pay more for the one with a documented 92 per cent state of health and an owner who can explain how they charged it. Look after the battery and it will look after your range, your running costs and your resale value in equal measure.