Getting to grips with EV terminology
This is the measurement of energy transferred in one hour by 1kW of energy. So a 7kW home charger delivers roughly double the amount of energy than a 3.7kW home charger in the same time.
Thus the bigger the car battery, the further the car can travel. Think of it as the difference between a conventional fuel tank that holds 30 litres and one that holds 70 litres. A car with the 70 litre fuel tank will go twice as far as the 30 litre tank car.
There are several connection types. Generally most modern cars are now Type 2 with a seven pin plug; early plug-ins were Type 1 with a five-pin plug - the Mitsubishi Outlander PHEV 2019 model year still features a Type 1 connection.
Other connector types are CHAdeMO - for fast charging (typically Asian-built models). Or Combined Charging System (CCS) - the EU standard for fast-charging.
This is a measurement of miles of range per hour.
Cost to charge
The cost to charge an EV depends on its battery size. The greater the capacity of the battery, the more it will cost to charge.
A Tesla Model S 100 has a 100kW battery. The average cost of electricity per kw in the UK (February 2019) was 13p.
Therefore a Tesla will cost about £13 to fully charge. Whereas a Volkswagen e-Golf has a 36kW battery, and would cost £4.68 to charge.