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!
Standard charging speeds
2.3kW (AC)
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)
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)
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. The number of public chargers at 11kW is lower than the options either side.