Efficiency? I thought range was the big concern
It’s true that range is lots of people’s primary concern with an electric car – but don’t forget about efficiency, either. Considering the former without thinking about the latter is like worrying about the size of your car’s petrol tank without thinking about its fuel consumption.
The trouble is, for a manufacturer it is easy to add range to a car by simply fitting it with a bigger battery. But a bigger battery adds weight, and that extra weight can mean these longer-range electric cars are less efficient, and will therefore cost you more to run – especially if you’re using public chargers all the time.
How do I find out an electric car’s efficiency?
Most manufacturers now list efficiency figures in their brochures; if you can’t find the figure, ask the dealer instead.
Different manufacturers use different units to measure energy efficiency, but here at The Telegraph we have decided it is simplest to use miles per kilowatt-hour (mpkWh). This makes it easy to work out how much a journey will cost you in an electric car: just divide the journey distance in miles by the efficiency figure in mpkWh, then multiply by your electricity rate in kWh.
What is a kilowatt-hour?
A kilowatt-hour, or kWh, is a unit of energy: 1kWh is enough energy to run an electrical appliance (in this case a car) with a power rating of 1,000 watts, or 1 kilowatt (kW), for one hour.
It might help to think of a kilowatt-hour as being a bit like a litre of fuel. Your battery (or fuel tank) can only hold so many of them; once they’re depleted, the car will stop.
If you have a bigger battery (ie one with a higher kWh rating), it will hold more charge – or fuel – and your car will travel further.
But equally, if your EV is more efficient, it will travel further on fewer kilowatt-hours, so it will cost you less, and you won’t need as big a battery.
Is charging an EV as complicated as it sounds?
It can be, but it’s getting easier. Nowadays many public chargers will offer instant payment via an app, so you don’t have to have a subscription like you used to, while many are now starting to offer contactless credit and debit card payment, too.
The network still isn’t as reliable as it needs to be, though, with users complaining of a high rate of inoperative chargers, but again this state of affairs is improving and reliability should also improve as newer chargers are rolled out across the country.
You also used to have to worry about which type of charging socket your car used – there were several at one point – but now most manufacturers have standardised around one particular type, called the Type 2/CCS charger. Almost every charging point will be compatible with this type of charger now.
How easy is it to get a charger installed at home?
Very. It’ll set you back about £800 (although there’s another government grant available here, which gives you a discount on the cost, taking that price down to about £300). Most chargers will come with fitment included in the price, and an engineer will install it for you.
You said it takes a long time to charge an electric car, but how long?
You won’t be in and out as quickly as you would stop for fuel, that’s for sure. But you won’t “refuel” in quite the same way, either. Think of an electric car as being a bit like your smartphone: it’s best if you plug it in to charge overnight so that when you want to use it in the morning the battery is full.
If your car needs more juice during the day, a quick blast at a rapid charger should provide enough to get to your destination. Some of the fastest chargers now being installed can charge at huge speeds – adding about 100 miles to your EV’s range in only 10 minutes.
Sounds great – can any electric car use these faster chargers?
No. An electric car is only capable of receiving charge at a certain rate and that’s limited by its on-board charging equipment. Today, the fastest public chargers in the UK are capable of charging at 150kW.
Charging speeds are measured in kilowatts (kW) – think of these as the number of kilowatt-hours you can add to your car’s battery in an hour. So in that time, a 50kW rapid charger will add 50kWh to the battery.
But if your EV is only capable of receiving charge at 50kW, that’s the fastest it’ll charge at, even if you are hooked up to a 150kW charger. So if you want to charge your car in double-quick time, you need one that is capable of being charged quickly.