Why the clock matters as much as the charger

If you have recently made the switch to an electric car, you will have noticed something fairly quickly: the biggest line in your running costs is no longer petrol or diesel, it is electricity. And unlike fuel, where the price is broadly the same whenever you fill up, electricity is priced by the hour. Plug in at 6pm on a weekday and you are buying power at the most expensive moment of the day. Plug in at 2am and you can pay a fraction of that for exactly the same electrons.

For most UK drivers covering a typical 20 to 30 miles a day, home charging does the heavy lifting. Get the timing right and those miles can cost the equivalent of two or three pence each — comfortably less than a third of what you would pay at a rapid charger on the motorway. The good news is that this does not require any great effort. It mostly requires a timer and a little planning.

How off-peak tariffs actually work

Off-peak pricing has been part of the UK energy market for decades, largely through Economy 7 and Economy 10 meters that offered a cheaper overnight window for storage heaters. Modern electric vehicle tariffs work on the same principle, but with windows designed around when cars tend to sit on driveways rather than when radiators need warming.

Most of these tariffs give you somewhere between four and seven hours of discounted electricity, often starting around midnight or in the small hours. The discount can be substantial — sometimes less than a third of the standard daytime rate. But there is a catch worth understanding before you switch.

• Check the length of the window. A very cheap rate is less useful if it only lasts three hours and your car needs five.
• Compare the peak rate, not just the off-peak one. Many cheap overnight deals come with a slightly higher daytime rate. If your household uses a lot of electricity in the evening, the savings can shrink or vanish.
• Look at the standing charge. A low unit rate means little if the daily charge is noticeably higher than your current one.
• Think about what else you can shift. Dishwashers, washing machines, tumble dryers and immersion heaters can all run overnight too, which is often where the real savings appear.

A useful rule of thumb: if you do more than a few thousand miles a year and can move at least some other appliance use into the cheap window, an off-peak tariff is usually worth it. If you barely drive and run everything in the evening, it may not be.

Set it and forget it: scheduling your charge

Almost every home charge point sold in the UK, and virtually every electric car built in the last five years, includes some form of charging schedule. This is the single most useful feature for cutting costs, and it takes about five minutes to set up.

The simplest approach is to tell the car or the charger to only accept power during your off-peak hours. A slightly smarter version is to set a departure time — say 7:30am — and let the system work out when to start so the battery is ready just before you leave. That way the car is not sitting at a high state of charge for hours, and on cold mornings you can have the cabin warmed using mains power rather than battery energy.

Do check that it actually worked the first few times. A quick glance at your charging app the next morning will confirm the session ran in the cheap window, and your energy provider's app will show the cost split between peak and off-peak usage.

Getting more out of every cheap hour

Charging speed affects efficiency more than most people realise. A standard 7kW home charger is a good balance, but the humble three-pin granny cable is noticeably less efficient because the car's onboard equipment has to work harder for longer. If you have a short off-peak window, a faster charger means more of your energy lands inside the discount.

Battery size matters too. A car with a large pack may need more hours than a single overnight window allows, so you might alternate: charge on Sunday and Wednesday nights rather than every night. If you have solar panels, an off-peak tariff still helps — you can charge from the roof during the day and top up cheaply overnight when the sun is not cooperating.

Public charging follows the same logic

Off-peak pricing is not limited to home electricity. Several public charging networks charge less overnight, and some offer membership plans that reduce the per-unit rate in exchange for a monthly fee. If you cannot charge at home — a common situation for flat dwellers — this is worth investigating, along with overnight destination charging at hotels and car parks.

What you want to avoid is the motorway rapid at 5pm on a Friday. That is peak demand, peak pricing and, often, a queue. Where you can, shift a long journey's top-up to an early morning or late evening stop.

Small habits that add up

• Keep tyre pressures correct; under-inflation quietly steals range.
• Use regenerative braking by anticipating stops rather than braking late.
• Do not leave the battery sitting at 100% if you do not need the range — 80% is kinder to it and to your wallet over time.
• Review your tariff once a year, as off-peak windows and rates change.
• Combine a top-up with a supermarket or workplace charge point if one is available at a low rate.

None of this is complicated, and most of it is a one-off setup. Set your schedule tonight, run the washing machine while you sleep, and let the cheap hours do the work.