Power and Connectors
Power is the measure of how fast energy moves into your car's battery. It is measured in kW (not to be confused with kWh), and the so-called "standard" charging rate, which is very common on home chargers, is 7kW.
Asking what power you need to charge at is analogous to asking how quickly you want fuel to flow from a petrol pump into your tank. The difference is that petrol flowed so quickly, the whole thing was always over in a matter of seconds.
Electrical energy doesn't tend to flow so quickly - continuing with the liquid flow analogy, charging under 7kW is known as "trickle" charging. You may have to pay a premium on your energy to get it into your car quickly!
Contents
- Typical charging power ratings in the UK
- The weakest link: factors that affect charging power
- Connectors
Typical charging power ratings in the UK
2.3kW (AC, "granny")
If you plug your car into a domestic wall socket in the UK, you are likely to draw energy at 2.3kW. With battery capacity on premium cars reaching three figures, you might need over 40 hours of continuous charging to fill a battery at this speed!
Moreover, arrangements with domestic wall sockets can be unsafe.
3-5kW (AC, "slow")
Lamppost chargers tend to run at powers which are not much higher than domestic plug charging, because it is difficult to get a higher load from a streetlight.
There is debate about whether this kind of charging will always be appropriate for the public. While they are slow, lamppost chargers are often the cheapest to install and the easiest way to ensure a short walk home from a charger, and they also offer lower tariffs than higher power chargers. Some people predict that public charging customers will either optimise on price (which means trickle charging) or time (which means ultra-rapid charging), while demand for chargers which compromise on both will shrink.
7kW (AC, "standard")
If you are in the market for a home charger, the default option is usually 7kW. This will fill up a 100kWh battery inside 15 hours, and a cheaper lower-range car quicker than that. Many people plug in every night after they've used a fraction of the battery capacity and wake up with a full battery again.
Like lamppost chargers above, public 7kW chargers fall into the category of cheaper, low-power chargers prioritised by some public charging schemes like LEVI.
11kW (AC)
The next step up from 7kW is 11kW, which is often a premium option for home chargers. 11kW chargers require three-phase supply, so you may need to undergo grid upgrades to make this an option at your home.
The number of public chargers at 11kW is lower than the options either side, probably because once you have a three-phase supply, you might as well maximise power on each phase to get 22kW.
22kW (AC, "fast")
22kW tends to be the highest power category for AC power, because your car's on-board charger will not be able to convert higher power to DC.
Not all cars can accept 22kW AC charging. If the on-board charger is single-phase or only 16A, then your car will draw power at a slower rate.
50kW, 100 kW, ..., 350kW (DC, "rapid"/"ultra-rapid")
To reach charging powers above 22kW, DC power is necessary. DC chargepoints don't differ so much by situation, so the questions which separate DC powers all the way from a 50kW to 350kW and beyond will be: what charging power your car can accept, how much you are willing to pay, and how quickly you want to charge.
While AC chargers may come with tethered cables or may rely on you bringing your own charging cable, all DC chargers come with tethered cables.
The RAC place the threshold between "rapid" and "ultra-rapid" at 150kW. Anything 150kW or above is "ultra-rapid".
The weakest link: factors that affect charging power
If a charger says 350kW, that doesn't necessarily mean you'll get your energy that fast. Your car will have a maximum charging power, which is something to consider when deciding on which electric car to choose.
Moreover, some chargers perform load-balancing, which means that if several cars are charging at once, you might get a lower charging power.
The phase and capacity of your car's on-board charger affects the maximum AC charging power, but will be irrelevant to the maximum DC charging power, as DC charging bypasses your car's on-board charger.
The power flowing into your car will be the lowest of the car's maximum charging power and the socket's output given the conditions of the time.
Battery protection and charging curves
Even cars which can take in energy at over 100kW will not do so if their state-of-charge is near 100% already. This is to protect the battery from damage. For this reason, many people stop their charges at ultra-rapid chargepoints when they hit 80%.
The relationship between maximum charging power and state of charge of the battery can be represented graphically as a charging curve. The Fast Charge have an excellent article on charging curves, and the article in turn refers to research by German consultancy P3 on the topic.
AC/DC
Without delving too deep into what alternating current and direct current actually mean, the rules are that your car battery likes DC whereas the distribution network of electricity to your home and public chargers is AC. Therefore, the current needs to change from AC to DC between the distribution line and your car battery.
At low powers, this is done by your car's on-board charger.
However, the on-board charger will not accept more than 22kW, even if the battery itself will. To get higher power than this, the conversion from AC to DC must be done by the chargepoint itself before energy comes through the cable to your car. This bypasses the on-board charger.
The equipment to convert AC supply makes DC chargers more expensive to install. They also tend to charge higher tariffs.
Single phase v three phase
Domestic electricity supply is usually single phase, whereas commercial and industrial supply is usually three phase. Three-phase supply can bring in three times as much power. Not all cars have a three-phase on-board charger, and those without are at a disadvantage for the higher end of AC charging.
Connectors
Type 2
You can spot these all over this website! Two pins/holes in the top row, three in the middle row, and two in the bottom row. Type 2 chargers have become standard in the UK and Europe.
Combined Charging System (CCS) Combo 2
These are similar to type 2 connectors except they have two extra big pins/holes underneath, and skip some of the Type 2 pins. The beauty is that CCS Combo 2 inlets accept both CCS Combo 2 and Type 2 connectors. You would use the extra two pins of a CCS charger if using a high-power DC charger.
While CCS Combo 2 has become the standard for ultra-rapid charging in the UK and Europe, it is not as universal as Type 2 for low-power charging because it was competing with CHAdeMO (below) through the 2010s and early 2020s.
CHAdeMO
EVs in the UK by Japanese manufacturers may have CHAdeMO sockets for high power charging. In 2025, the last car to include CHAdeMO inlets in the UK, the Nissan Leaf, switched to CCS inlets for ultra-rapid charging.
An EU directive mandates that all high-power chargepoints offer CCS Combo 2, which is seen as a step towards phasing out CHAdeMO.
Nevertheless, it is not difficult to find CHAdeMO connectors at ultra-rapid public chargepoints in the UK as many ultra-rapid chargepoints have both CSS Combo 2 and CHAdeMO.