Posted: 24th February 2026
What is the Difference Between Slow, Fast, and Rapid EV Chargers?
There are three main ways to charge your electric vehicle, we generally categorise these as slow, fast, and rapid. While the names give you a basic idea, the real difference lies in how they actually fit into your daily life and the long term health of your EV batteries.
In this article, we will break down the different charging speeds, where you will actually find them, and how many miles of range they add while you wait. Most importantly, we will provide a practical recommendation on which one is best for your specific route.
Slow EV charging
A slow charger typically operates between 2.3kW and 3.6kW. These usually come in the form of a standard three-pin plug which many people call a “granny charger” because it is often seen as a backup option for visiting relatives. You might also see dedicated 3.6kW points installed on older driveways.
You will mostly find these in homes or older workplace setups. While they get the job done, they are not a long term solution for the modern driver. One major expert tip is to check your socket regularly if you use a three pin plug. These sockets are not always designed to run at full power for ten hours straight, so they can get quite warm. If you are a business owner, relying on these means you are missing out on dedicated infrastructure and government grant funding that can cover a significant portion of your installation costs.
Fast EV charging (The Home Standard)
In the UK, 7kW, 11kW, and 22kW units are all considered fast chargers. If you have a charger at home, there’s a 9/10 chance that it is a 7kW unit. This is because most UK homes have a single phase power supply which is physically limited to this speed. Even if you buy a 22kW charger for your house, your car will likely still only charge at 7kW unless you pay thousands to upgrade your entire property’s electrical incoming supply.
What this means in miles per hour
A standard 7kW home charger adds about 25-30 miles of range for every hour it is plugged in. This makes it perfect for overnight charging. If you plug in at 9 PM, you will have a full battery by the time you leave for work.
One thing the big advice sites often miss is the choice between tethered and untethered units. A tethered charger has the cable permanently attached, which is much more convenient when it is raining. An untethered unit looks neater on the wall because you hide the cable in your boot, but it means you have to get a wet cable out every morning. The choice usually comes down to whether you prefer aesthetics or convenience.
Rapid and Ultra-Rapid EV charging
If you are on a long motorway journey across the UK, these are the chargers you need. Rapid chargers usually sit around 50kW, while ultra-rapid units can go anywhere from 100kW up to a massive 350kW.
The “Charging Curve” and the 80% Rule
EV charging experts often talk about the “charging curve.” This simply means that your car charges much faster when the battery is low. A 150kW ultra-rapid charger might add 100 miles of range in just 15 minutes if your battery is at just 10% remaining.
However, once you hit 80%, your car will automatically slow down the speed to protect the battery cells from heat damage. Because of this, we recommend only charging to 80% at motorway stops. The last 20% can often take as long as the first 80% to complete. On a busy motorway, staying for that last bit is not just bad for your battery health, it is a waste of your time and blocks the charger for others who might be waiting.
Getting the speed you actually pay for
One thing to remember is that in a cold UK winter, a rapid charger will start much slower than usual until the battery warms up. To avoid this, you should always put your motorway charging stop into the sat nav. This tells the car to pre-heat the battery while you are driving so you actually get the 150kW speeds you are paying for the second you plug in. Without this, you might find your “rapid” charge feels remarkably slow for the first twenty minutes.
Final thoughts
For most drivers, a 7kW home charger is the best daily solution, with rapid chargers reserved for long trips. However, commercial charging is more complex. At ElectrAssure, we specialise in commercial charging, helping businesses like National Grid and Volkswagen. If you have a fleet and want to talk infrastructure, then please do contact us today for a no-obligation chat with our team.