One of the most frequently asked questions after "how far can it go?" is "how do you charge it?" with the variation "how long does it take to charge?". And its not a simple answer. In section we cover the types of chargers, the networks, how to find out what you need and a few other hints and tips in charging.
Before we get into the detail, an electric car is just like any other car, the distance you can go on an amount of fuel varies by how you drive, and even the weather. The range of the cars is also stated as a figure laid down by a formal testing policy which is more than a little over optimistic. Tesla therefore have 3 range figures available, the Rated (unrealistic but regulations dictate), the Typical (better but can still be a bit high), and a third option only shown on the big screen under energy consumption based on recent average. Do not be disappointed when your 300 mile rated car can only do 240 miles just as your 53mpg car could only do 41mpg.
Before diving into the detail of charging options its worth explaining the basics on what all the different terms mean
This is the amount of electricity and is equivalent to how many gallons you might put into a petrol car. A car with a 85kwh battery is like saying a car has a 10 gallon petrol tank.
This is a term that you don't really have an equivalent for on petrol cars, or certainly not one that doesn't make it more confusing. kw is the rate of energy flow. When charging, it's the rate at which energy is being put into the battery. The nearest thing in a petrol car would be the how fast you can fill your petrol tank up, something that simply isn't quoted. In it's simplest form, if the rate of flow is 7kw, in an hour you can put in 7kwh.
Where it gets a little confusing is on an electric car, the power dial on the car is also measured in kw. This is how much energy is being taken from the battery to propel the car, the more thats taken, the more energy being used to accelerate the car and overcome wind resistance etc. On a petrol car we would probably measure this using bhp.
When you charge your car you can use either AC or DC. AC is the type we get at home through the sockets on the wall. The rate of charge (in kw) is the product of our voltage and current. We operate at 230 Volts in the UK (not the 240V people often think it is), and at 16 Amps we'd get 230 x 16 = 3680 Watts or 3.7kw (the k standing for 1000). Equally at 32 Amps we would have 230 x 32 = 7.4kw. When charging, the voltage can fluctuate a little and as a result these numbers can go up or down a little.
In the UK, we also have 3 phase power supplies, some houses have these as do factories etc. In essence, this is like having 3 separate 230V power supplies, all slightly out of step with each other. The result of this is that when taking 16Amps on a three phase supply, you have 3 x 230 x 16 = 11kw. Some older Teslas can take 32 Amps giving 3 x 230 x 32 = 22kw but later cars with the high power charger are limited to 24A giving 3 x 230 x 24 = 16.5kw. Remember, this is the rate at which you can fill the battery.
The batteries themselves are DC, just like a AA battery is DC. As a result, the cars can also charge using a DC supply which is what you get at super chargers and chademo type chargers. As the batteries are DC, the car does not need to convert the power from AC to DC and can therefore accept much high charge rates. The charger will match the voltage of the car battery (they differ slightly depending on the car model and the state of charge) and then send down as much current as the battery can safely take. The battery voltage can be around 400v, and the current can be as high as about 300Amps leading to approx 400 x 300 = 120kw.
Your car will have a battery which will have a capacity, something like 85kwh, in petrol terms that would be a tank of say 10 gallons.
When charging, the rate will vary depending on what you are using to charge, but typically this may be 7kw at home. If your battery was empty (which is unusual), at 7kw it would take 80 kwh / 7kw = 11.5 hours to fully charge - ie you would need to be adding 7kw for 11.5 hours to add 80kwh. If you were on a faster charger like a DC charger, because the rate is much higher, the time is much less. On a Super charger delivering 100kw, the time would be 80 kwh/100kw = about 50 mins to go from empty to full.
But.. the rate will vary over time, especially on a super charger which slows down as the battery fills up to protect the battery, due to cold batteries in winter etc, hence why there is some variability. Charging also has some wasted energy so a little is lost in the process, but the broad principal is correct.
Teslas have used different AC chargers in the cars over the years.The maximums are 16A 3 Phase (ie 11kw, potentially all cars without an uprated charger), 24A 3 phase (ie 17kw, the High power charger option from 2016) and 32A 3 phase (ie 22kw, the twin charger option prior to 2016). When charging on AC, once the car limit has been met, it can not charge any quicker, irrespective of the capabilities of the charge point.
While quoting kw and kwh is technically correct, it's not very intuitive to many. To try and help, although arguably it adds to the confusion, we sometimes quote how many miles are being added or have been added. This is like saying instead of a 10 gallon petrol tank, we say it has a 400 mile tank (assuming 40 miles per gallon). Its only an approximation as the actual number of miles will vary depending on how you drive, weather etc.
What we can do however is say for an Tesla you get approx 3 miles for every kwh of energy stored in the battery. If we are using a 7kw charger, and as 1kwh = 3 miles, in an hour we have added 7kw x 1 hour x 3 miles per kwh = approx 21 miles or we can say we're charging at 21 miles per hour (mph).
When you charge you are adding energy to the batteries and the rate at which that happens depends on the way you charge. We've included a MPH figure for each type as drivers tend to find it easier to thing this way however this is only indicative and can very between cars and there is no guarantee that adding 25 miles of range will actually mean you can drive 25 miles, in the same way a petrol car that does a theoretical 45 mpg will actually do 45 miles on a gallon. Most users will want to charge in one of the following ways:
At home using a commando socket - This is no more than a blue socket that allows 32A unlike a 3 pin socket that gives a maximum of 10A and about 6 miles of range per hour. To use either, you need to plug in a cable with the appropriate electronics to work (called a UMC), and Tesla supply this with the car. You'll get up to 22 miles per hour of charge with a commando which in nearly all cases leaves you with a charged car in the morning. Be mindful of the smaller blue commando sockets that are limited to 16A and often found in marinas, caravan parks and some ferries, the standard Tesla plug will not fit. You can also get a red 3 phase commando socket. Tesla sell an additional adapter to use these and the car will charge at approx. 33 miles each hour. If you opt to use the 3 pin plug, even though this is by far the slowest way of charging, you must be careful to not overload a circuit, especially if you are using an extension cable.
This is effectively a box on the wall that has the electronics built in, rather than the UMC mentioned above. They can come with either a tethered cable or a socket. All you need to do is use the tethered cable, or if the version is one with a socket, a Type 2 lead to the car. These also typically charge the car at 22 miles per hour. You can get 3 phase versions including 32A ones which will be pretty quick, but they cost a more and require 3 phase supply to your home. They about 50% quicker unless you have dual chargers or the high power charger option in your car. The preference over Commando and a charge point, and whether to go tethered v untethered are all personal choice and often influenced by the grants available. Tesla make the nicest version but its also the most expensive.
Tesla Superchargers just need plugging in and depending on a whole host of factors can put in anything up to 360 miles per hour. The more the car is charged, the slower it gets so they work fastest when arriving nearly empty and charging to about 70%. Tesla are also a little sneaky as chargers are in pairs and both can't deliver the maximum charge rate at the same time. So, if you have a choice, always be the only car on a charger pair (they have 1A and 1B written on them). As one car fills up, it charges more slowly releasing more capacity to the second car. The belief is newer chargers may cure this as they have local storage facility but there is no evidence of this yet. It's worth noting that the all-inclusive super charging stopped for cars ordered after mid Jan 2017 and delivered after March/April 2017. Older cars will continue to get the benefit. Newer cars will have a limited amount for free and then will need to pay extra unless you buy using a referral link, however this is only for the first owner so buying a used car from 2017 is unlikely to have free unlimited supercharging even if the current owner shows that it does. While you may think a private sale means Tesla won't know, you will need to register the car in your name with Tesla to be able to use the app and prevent the old owner from accessing your car. Tesla have introduced penalty charges for leaving your car connected after charging has completed. In essence, the resources are scarce and Tesla are looking at ways to reduce demand and maximise availability.
While the connector will fit in other makes of car, a super charger will not work with any car other than a Tesla.
Rapid chargers like the ecotricity points you see at service stations, are best used using the Chademo adaptor (which costs around GBP 450). This allows DC charging which is quicker at around 120 mph than the AC charging they also offer. Other than the Chademo adapter, all the cables are there. That said, many providers are now charging for use. It is however the second quickest way to charge the car and possibly faster than a supercharger under certain situations. With the increase in destination chargers and super chargers, the need for a Chademo connector has reduced and we recommend you only buy if your travels dictate you may need it.
These are slower and similar to the charger you may have at home. They typically all charge at 22 miles per hour, although some are only half that, and can be found in some car parks, railway stations, restaurants, hotels etc. The idea is you will be leaving your car there for a while so a slower rate of charge is fine. Tesla have their own destination chargers which look identical to the one you may have at home. The Tesla chargers usually have red and white signs behind them, the red will only work with Teslas, the white with any EV. Others require you to use your own Type 2 cable. These are latched to the car so can't be stolen while you are away and are typically started with an app or membership card.
These are like other destination chargers although they can often be 3 phase which gives a charging boost and sometimes load share where one charger will deliver as much as it can, but if two chargers are in use, the power supply may be split so that both cars can charge. They are also tethered so you don't need a cable. These tend to be found at hotels, restaurants, and other places where you might want to visit and if you are reliant on the charger you should ring ahead to check access, many places require you to use their facilities although they may offer the charging for free in return. Look out for the signs behind the chargers, those with a red back are for Tesla cars only, the white back are suitable for any car that can take a Type 2 cable.
Many EV owners charge their car over night at home and rarely need to charge on a public network. Others travel extensively and rely heavily on them. But all owners need to be aware of what networks exist, how much they cost, and what you need to be able to use them.
A word of warning when using any charger. Most chargers are effectively in a car park, and terms and conditions apply. Please don't assume parking is free, sometimes it is so long as you register at the reception, but people have been caught out. Similarly, many motorway services have a 2 hour free parking limit, and while you should be able to charge in that time, its possible that you could overrun especially if you have to wait for a free charger.
Free for cars delivered before April 2017, 20p kWh for cars registered after then.
Breaking news suggests free unlimited charging is back... watch this space
No app required.
These are the Tesla superchargers you find at some motorway services and selected other locations. They ONLY work on Tesla cars even though they use a Type 2 plug - so just because it fits in a different make of car, it doesn't mean it’s working.
Free although aimed at those owners who are using the facilities at the location.
No app required.
Like the zero carbon world scheme, these are aimed at places where you will be leaving your car while using the venues facilities. The chargers should be free, and typically you may find 2 or 3 of the chargers, with some dedicated to only Tesla cars, and others which will work with any car that takes a Type 2 plug.
£7.85 per month after an initial 3 free months.
Either free or 9p/kWh + VAT
App or RFID card
Sometimes refered to as Chargemaster, they operate two schemes, this one and Polar Instant (see below).
You receive a membership card as part of your subscription and these are used to start a charging session.
Located extensively in London and Birmingham but have a smattering acoss the country, many at Asda stores.
£1.20 admin fee per use.
£1 or £1.50 per hour for AC charging units.
£6 for 30 mins for rapid chargers.
As above, sometimes known as Chargemaster. This is the fully pay as you go option and ideal for those that would not use them on a regular basis.
Located extensively in London and Birmingham but have a smattering acoss the country, many at Asda stores.
£20 annual fee for the RFID card or use the free app. Some points have poor reception so the RFID card may be needed in remote areas or underground car parks.
£1 connection fee, although varies
CYC administer the use of other enterprises charging equipment so you sometimes find them in city operated car parts (Greater Manchester being a main one) or even across whole areas like Scotland.
Located extensively around Manchester, Bristol, Newcastle and the south east plus right across Scotland.
£3 for 30 mins on a rapid charge +17p per kwh using their App
Slower, standalone AC chargers are free (but require the RFID card)
Their domestic customers get the connection fee waived.
Ecotricity are located at many motorway service stations and other strategic points across England and to a lesser extent Wales. They mainly focus on Rapid chargers where you will wait near the car for charging to complete.
£12.50 for an RFID card. The App is free.
Most points are free although some charge.
They aim to have a wide network at places where a car may be left for an hour or more.
Located at a mixed bag of locations including various retail destinations across the country.
Free app or £9 RFID card
30p kWh, plus a connection fee of either free, 50p, £1 or £1.80.
Similar to the CYC and Polar networks in use, these types of companies tend to be strong in certain geographies, and almost none existent in others.
One for your holidays, located in Devon and Cornwall, the lakes and a few around Southampton area.
How much does it cost? A year ago, most charging was free with a few exceptions. There is however an increasing trend to charge for public use although some hotels and councils still offer free charging. The charges are also getting close to the price of fuel for a diesel or petrol car. As an example, Ecotricity have introduced a £3 fee for their Rapids plus 17p per kwh. A 30 min charge may cost £3 plus 20x 17p = GBP6.40 and this will be approx 60 miles - thats approx 10p per mile. This is comparable to an efficient diesel car. At home, it depends on your tariff, but typically Economy 7 stars at 6p and a green eco tariff may be 15-20p per kwh. At an average of 10p a kwh this works out at approx 3p per mile. Super Chargers are mostly free (* see note above), as are some destination chargers.
Common to all electric cars are public charging locations. These come in a variety of forms and the proliferation varies from areas to area. We cover the various schemes like Ecotricity, Polar and Charge Your car (CYC) on a different page but it initially makes more sense to describe how you find out which ones are on your travels. For instance there is no point signing up to Ecotricity only to travel around Scotland where they are mainly CYC.
Plugshare list all the sites and you can filter by car type or charging point type so you can see what is available and which network they belong to. I believe the data to be fairly accurate but it is often left to members to correct the data and report failed chargers.
Zapmap is very similar to Plugshare and the combination gives a near 100% coverage in the UK.
The final option is a site called EV Trip planner. This combines a navigation tool with charging locations and so enables you to plan lengthy routes more effectively.