Last updated on July 26th, 2022 at 10:55 am
Charging your EV should be easy. In fact, it should be as easy as the experience people have putting petrol in their internal combustion cars. But some of the time it isn’t. This is frequently used by EV haters as an excuse to avoid switching to an EV, or even to vocally criticise them on social media. However, a lot of this is merely a cultural change. In the same way that you need to avoid putting petrol in your diesel car (and vice versa), an EV owner needs to know their CHAdeMO from their CCS, their AC from their DC, and other characteristics of their vehicle’s charging capabilities. This WhichEV guide is here to help you navigate the cultural shift, to help you make EV charging easier.
How far does an EV really go on a single charge?
One of the first realisations that tends to puzzle new EV users is what the real range of their car is. Like the miles per gallon rating of a fossil fuel car, the WLTP range of an EV tends to be optimistic. This isn’t because EV manufacturers are liars, but because of how the WLTP rating is calculated. The WLTP rating doesn’t involve days of real-world testing in numerous conditions; it’s a 30-minute drive over a 23km distance equally divided between urban and extra-urban roads.
In complete contrast to petrol and diesel cars, EVs tend to be more efficient in urban conditions than they are on highways. This is a lot to do with wind resistance, which increases exponentially as you go faster. Of course, this also affects internal combustion cars, but they are so uneconomical in urban conditions that motorway driving looks like an improvement. With an EV, it makes a big difference as you go above about 50mph, and even more of a difference if you decide to exceed the UK national 70mph limit. Go well beyond this and watch your EV’s range drop like a stone (on a private track of German Autobahn, obviously).
It is possible to even exceed an EV’s WLTP by driving a constant speed below 60mph, not accelerating much, and in good weather (neither too hot nor too cold – of which more later). But, in reality, you should assume your car’s range is about two thirds of the WLTP rating under normal driving conditions. You will probably do considerably better than this, but to avoid “range anxiety” (worrying about whether your battery will last to your destination), having this in mind as your base figure will help avoid unnecessary anguish. In other words, if your car specification says it has 300 miles of WLTP range, we would recommend having around 200 miles in mind as the true effective range.
The in-car remaining range indication can be more or less accurate, depending on brand, so you should really get to know your car’s characteristics – and work with the percentage instead when calculating trip distances. One final thing to consider is that most EV batteries are best kept at 80% or under for everyday usage, so unless you are going on a long trip, only charge to 80% on a regular basis. It’s also not recommended to go below 20% for extended periods. The one exception to this rule is the current Tesla Model 3 base model, which uses a type of battery called LFP that doesn’t have the same problems with being fully charged all the time.
How much does cold weather affect EV range?
Another popular criticism of EVs by non-enthusiasts is that they only go half the distance in cold weather. This is another partial myth, however. It is true that cold weather does affect the range of an EV – and so does rain, which increases air density, adding extra drag. In both cases you also need to run the heater, including to demist windows. As an EV doesn’t have a hot engine to use to supply its heater as a by-product, it needs to use a separate heating element.
However, an increasing number of EV models now employ a heat pump instead of a heating element, and a heat pump is about four times as efficient. This can drastically reduce the depletion from heating an EV in cold weather. At the end of 2021, a report by Recurrent showed how the range varied for a variety of popular EV models in freezing temperatures versus 70F (21C), which is generally considered the optimum ambient temperature for driving an EV. Teslas, which generally have heat pumps, lost virtually nothing, but the worst cars lost 30%. That’s not great, but it’s nothing like “half the range”, and most recent EVs don’t fare that badly. A Nissan Leaf 62kWh lost just 14%. An EV also uses energy with air conditioning, but so do internal combustion cars. It’s not so obvious, but if you turn on an ICE car’s air conditioning it will use up a little more petrol running the compressor to operate it.
The EV range loss in extreme temperatures isn’t just from heating or cooling the passengers. The batteries also have an optimal operating temperature. But virtually all contemporary EVs have thermal management systems that mitigate for this effectively.
How to handle a long-distance trip
Once you’ve established a basic estimate of your car’s real-world range, the situation where this is most likely to be important is a long journey. If you have convenient local charging, especially home charging, and your regular daily journeys are well within the range of your car, it almost doesn’t matter what its range actually is. Just keep it topped up when you can.
Long journeys, however, need more thought and preparation. Start off with as close to a 100% charge as you can manage. Then fire up your favourite charger location app, such as Zap-Map, PlugShare, or the app for a preferred network with a good reliability reputation such as Osprey or InstaVolt. Some cars will have good charger location “points of interest” stored in their satnavs, but it’s usually better to plan before you start driving as much as possible.
Although you can run your car right down to 0% if you want, this is not a recipe for a calm trip. Instead, we would recommend you aim for a charge around 20%, or 10% at a push. In other words, your first stop should be within 80% of your car’s range. This may mean getting out a calculator. Taking our example of an EV with a 300-mile WLTP range, this would have 200 miles of safe “real” range, so 80% of this figure is 160 miles. On British motorways and A roads, this is likely to be 2-3 hours of driving, which is a good time to take a rest stop anyway.
As we will explain in a later section, it is usually recommended to charge your car only to 80% on a rapid charger, or 90% if the location isn’t busy and you need a few extra miles. So that means your next journey section will be a little shorter. For our 300-mile WLTP car, you are now using 60% of the range, so that would be 120 miles of real range. However, if your next stop is your home or a destination where you are certain of getting a charge, you can go a bit further.
Of course, you can greatly improve your range and time between stops by “hypermiling” (driving as frugally as possible) and stopping at 10% while charging to 90%. But for a new EV user, the rules of thumb we have suggested are the best route to an easy, range anxiety-free life.
Where can I find a public charger?
Now that you’ve worked out approximately where your journey stops should be, the next consideration is – where should you charge? Early EVs had really small batteries and took ages to charge, causing considerable “Range Anxiety”. But now even budget cars like the MG5 have a WLTP range of 250 miles, so range anxiety has been replaced by something we call “Destination Anxiety”. You may know that your EV can reach the next public charger location – but will it be available and working when you get there?
This is where products like Zap-Map are incredibly useful, because you can filter for the type of charger you are looking for, and you can put in a general location, to find more than one option in the area you need. However, most of the information about whether a destination is working depends on other users updating Zap-Map, which is far from universal. The advantage of using an app from a network provider, such as Osprey’s, is that it will give you live info about whether the chargers are working and available.
Another thing to consider is how many chargers are at your destination. The more there are, the better, because even if they are all taken when you arrive, the chances are that someone will be close to finishing. The impact of a faulty unit is also reduced. Think of this like a queue in a shop. One till can go wrong, but finding four, six or more together means you’re likely to get served quickly anyway by another till. Hubs like the one at Banbury in the video above have multiple high-speed chargers available. Charging forecourts like the ones being installed by Gridserve have so many chargers that they will only ever be unavailable if they have a total power failure.
How long does it take to charge an EV?
In every review that WhichEV does, we give the times to fill a battery using a slower AC charger. So if you have specific car in mind, search for the review on WhichEV and we’ll explain in detail how that car works. In general, the time taken will depend on how big your battery is and how fast the charger. Capacities vary a lot but, in 2022, a 40kWh battery would generally be considered quite small and an 80kWh battery is large.
With AC charging, the “charging curve” is usually almost linear, at least up to 11kW. So, with a home charger delivering 7kW, you can do the maths yourself. A 40kWh battery will take a little under six hours from empty to full. Even a huge 80kWh battery will take under 12 hours. Since you’re probably very rarely, if ever, going to let your EV hit zero charge, you can safely assume that a home wall box will fully charge your car overnight.
But DC charging is very different, for several reasons. First, the maximum DC rate of EVs varies a lot between brands. Some earlier designs, such as the BMW i3, have a DC maximum of just 50kW. But some recent models go well beyond this. A Tesla Model 3 Long Range or Performance can charge as high as 225kW, and the Porsche Taycan has a fast maximum too. Recent cars such as the IONIQ 5 and Kia EV6 with 800V systems can go even faster.
To help you find out the maximum charge for your EV, Osprey has created a useful online tool that will tell you precisely how fast your EV can charge at Osprey’s various charger types. This is a great way to see what your maximum could be.
But DC charging is most definitely not linear. You cannot simply divide your battery size by the maximum DC charging power. In fact, there is a definite curve to every EV, and a fast top DC rate doesn’t necessarily mean that a car will charge faster than one that has a lower headline DC rate but can sustain that for longer. The Tesla Model 3 Long Range can only charge at its maximum up to 40% or so, and then drops quite rapidly. An Audi e-tron Quattro 55, in contrast, has a 150kW maximum but can maintain that up to 80%, before dropping off very sharply. Charging network Fastned has tested a wide variety of EVs on its rapid 300kW chargers, with full graphs available showing their curves.
It's not going to be very easy to use this information to work out how long your car will take to charge on a given DC charger to the exact minute. Other factors such as starting state of charge, ambient temperature, and whether battery preheating has occurred will affect speed too. However, in all cases the fastest charging happens up to 80%. This is because charging to full at very high speed can damage EV battery cells. It’s not a factor with AC charging because that is slow, but with DC it will drop down to AC rates for the last 20% to protect the battery.
In other words, once your DC charge goes beyond 80%, it’s likely to take as long to get from there to 100% as it did for the rest of the charge. That is bad for people waiting (see etiquette below) and it’s a real time waster. So our advice is budget for 80% charges at public DC chargers, or 90% if desperate, as we already stated.
Also bear in mind that DC chargers vary greatly in speed too, from 50kW to 350kW. The Osprey chargers in our video above give up to 125kW, and up to 150kW with the latest 800V-capable cars. But they also load balance across the devices, which is common with several networks. So you may not get the full DC level even if your car is capable of it and at the right state of charge to receive it. We have a section below on the variety of charger speeds you might encounter.
Most modern EVs will take less than an hour to go from 10% to 80% with a fast enough DC charger, and some will take considerably less. Check out our reviews to see the stated time for your EV. Even with a slower EV, stopping at a rapid DC charger will only take about enough time to use the facilities, get a drink, or eat something and browse one of the shops – then your EV will be ready to go. You will probably need this every 2-3 hours anyway, so it’s not really the hardship that EV haters make it out to be.
How much does it cost to charge an EV?
Although petrol and diesel prices have gone up a lot, and do vary from pump to pump, the cost of charging an EV varies a lot more. Some network plans include “free” charging (although you pay a static monthly fee and there is usually a cap on how many miles). You can also get night-time home charging electricity supply deals that cost as little as 7.5p per kWh (it used to be 5p until the recent increases). If you can maximise the use of this tariff, you could charge your 80kWh battery EV from zero to full for just £6. Considering you will get well over 200 miles from an EV with a battery this size, that’s less than 3p a mile.
Ad-hoc public charging prices also vary a lot. At the time of writing, slower chargers cost around 32p per kWh, which isn’t much more than the average home electricity supply, going up to 72p for IONITY’s 350kW ultra-rapids. But most rapids are now well over 40p, getting close to 50p per kWh. The Osprey chargers in the video above cost 49p per kWh when we shot the footage, so an 80% charge from 20% on a 40kWh battery would be £11.76, and on an 80kWh battery it would be £23.52. That’s still very cheap, coming in around 10-11p per mile. A typical 40mpg petrol car would cost around twice that per mile at current fuel prices – and those continue to rise.
It's easy to see that charging an EV is way cheaper than filling up a car, but you want to do it at home as much as possible. Even at a typical current day time per-kWh rate, it’s going to be close to half the cost of public charging.
What is good public charger etiquette?
Given that your car will pick up a lot of mileage in the first half hour or so of public charging, it’s nice if you can stop at that point and make the charger available to the next driver. In fact, if you frequent EV groups online, you will see that overstaying on a charger is a regular bugbear for users.
Sure, if you really need 100% and you’re not making anybody else sit around who might need the charger, then you can wait the extra time. But when WhichEV did a survey of our readers, we found that most would like a break every 100-200 miles, which as discussed above will be within the “real-world” capabilities of most current EVs. So, in reality, an 80% charge will easily get you to your next personal resting point.
How fast is rapid?
Home chargers use domestic alternating current and range from 2kW to 3kW with a standard wall socket (also known as “granny” chargers), to just over 7kW with the fastest home chargers that will be permanently installed at your house. You will also encounter AC public charging, as it’s common in municipal car parks, or at shopping and leisure centres.
These AC public chargers start around 7kW (although a few are slower) and they generally go up to 22kW, although only some cars support AC charging over 7kW. Lamppost street chargers will almost all be AC and can vary from 3kW to 7kW too. Ubitricity’s units tend to be around 5.5kW, which is still a good level for an overnight full charge.
DC chargers start around 50kW, but an increasing number are now over 100kW, up to 175kW. The V2 Tesla Supercharger has a 150kW maximum, but the V3 ones the company has been installing since 2019 go up to 250kW. There are even faster 300kW and 350kW ones at Gridserve Electric Forecourts, IONITY stations, and Fastned’s units at the Pivot Power hub in Oxford.
Although AC is great for a top-up, and perfect for overnight charging at home and on the street, if you really need a charge when you are out on a longer journey then you need to focus on DC chargers. While 50kW chargers are fine, 100kW chargers are better and anything over 100kW is what you really need to be looking for – if you want to “charge and go”, and your car supports it.
Read our previous article for more on charging speeds and connector types.
Charging ahead!
Those are some of the most important tips to smooth your charging experiences. Things will get easier as more chargers are installed, which received a boost recently from £1.6 billion pledged for public rollouts, including £450 million from the UK government. A lot more needs to be done. But if you get to know your car’s real range, where the trustworthy chargers are, and which apps can help find you a charger on the road, the EV life can be relatively hassle-free right now.