Buying an EV is fraught with new terminology particularly when it comes to EV charger types – but what does it all mean?
Life was a little bit simpler when all you had to do was pick between petrol and diesel and be on your way, but owning an EV doesn’t have to be complicated: in this guide we break down all the important terminology so that you can plug in with confidence.
AC and DC
One important thing to remember here is that the power output of the charger (measured in kW) is directly related to the speed that you can charge your EV. If you have a high-power charger, you can charge your EV much faster.
The mains electricity that we get in the UK is alternating current (AC), meaning that the current changes direction 50 times a second. This is great for transmitting electricity over long distances to peoples’ homes, however it’s not so good for charging EV batteries. To do this you need direct current (DC) which maintains a constant current over time.
Your electric car has an AC-to-DC converter inside of it which is used when you plug your car into a home charger or a three-pin plug. This converts the power from AC to DC which is then used to charge the battery. This convertor has a power limit though, which is why AC is usually referred to as “slow charging”.
- AC charging with a three-pin plug: 3kW
- AC charging with a 7kW home charger: 7kW (most common)
- AC charging with a 22kW home charger: 22kW
If you want to go faster, you need to use DC. When you charge your EV using a commercial DC charger it completely bypasses your car’s built-in AC-to-DC converter, meaning that you can get much more power. This is why DC is sometimes referred to as “fast charging”.
DC chargers are faster than AC, but they are expensive and require a dedicated power line so are only found at commercial charging stations. The power output that you can get from a DC charger can vary a lot depending on the specific charger that you are using, your car, and even the temperature. However, DC charging speeds can be several times faster than even the fastest AC chargers!
- DC charging at a Tesla Supercharger: up to 150kW
- DC charging at an InstaVolt charger: 50kW+
This technology is continually improving, and as the power output of chargers steadily increases, the charging time goes down.
The highest power output achieved to-date is 225kW for the Porsche Taycan, allowing it to charge from 20-80% in just 20 minutes at a fast charging station!
Plug Types
Numerous different types of plug exist for electric cars, so it is important to ensure that any charger you purchase is compatible with your vehicle. Having a good knowledge of your vehicle and the different types of plug it can accept is also very useful when it comes to selecting a public charging location – your choice of plug may limit your charging speed. In the UK there are currently four types of plug in use – two for AC charging, and two for DC charging.
Slow Charging Plugs (AC)
Type 1 – this is a slightly older American style of plug (also known as a ‘J plug’) which permits a maximum charging rate of 19.2kW. This type of plug isn’t very common on new cards in the UK, but can still be found in use on some older models.
Type 2 – this is the most common type of slow charging plug found in the UK and much of Europe, with vehicles such as the Nissan Leaf and the Tesla Model 3 using this standard. This has a much higher maximum charging rate of 50kW as it can be used in conjunction with a three-phase supply. This is a more advanced design, and is likely to replace the Type 1 standard entirely over the coming years.
Milebox installs both type 1 and type 2 home chargers.
Fast Charging Plugs (DC)
CCS – this is actually a modified version of the Type 2 standard – the plug looks just like a Type 2 plug with an additional section on the bottom which houses the DC pins. These large pins permit a (theoretical!) maximum charging rate of 350kW – it is uncommon to see this rate of charging in the real world but rates of up to 250kW have been observed. Tesla’s Supercharger network uses a particular version of this connector but unfortunately this is only compatible with Tesla vehicles for the time being.
CHAdeMO – this is a competing fast charging standard which permits charging rates of up to 400kW in its latest iteration (older versions are limited to 62.5kW) which was created in 2010 by a group of Japanese automakers. This is less common on new cars (used on the Nissan Leaf, for example) as it appears that the CCS standard is winning out in the UK.
