THE SHORT ANSWER
Divide the battery energy you need to add by the lowest power limit in the chain: the chargepoint, cable or car. A 7 kW home charger adds roughly 7 kWh per hour before losses, but a rapid charger does not hold its headline peak from empty to full.
Use energy to add—not total battery size
If a 60 kWh battery rises from 20% to 80%, it receives about 36 kWh. At a steady 7 kW that is just over five hours before allowing for losses and variations. Charging from a normal arrival level is therefore very different from a theoretical 0-to-100% time.
The slowest component sets the speed
A car with an 11 kW AC onboard charger will still charge at about 7 kW on a typical single-phase 7 kW home unit. Conversely, a powerful chargepoint cannot force a car to accept more than its own limit.
- Domestic three-pin connection: slow and best treated as an occasional solution where the manufacturer and installation permit it.
- Home wallbox: commonly around 7 kW on a UK single-phase supply.
- Public AC: the car's onboard AC charger may be the limiting factor.
- Rapid DC: bypasses the onboard AC charger, but battery temperature and charge level heavily affect speed.
Why rapid charging uses a 10–80% figure
Rapid charging follows a curve rather than a flat rate. The battery may accept high power when warm and at a moderate state of charge, then reduce power as it fills. That is why manufacturers usually advertise a 10–80% time rather than zero to full.
On a long trip, two shorter stops can sometimes be quicker than remaining connected while the final part of the battery fills slowly. The best strategy depends on the car, weather and the next available charger.
Check the handbook for your exact car
The manual explains supported charging connectors, maximum AC capability, battery preconditioning and any charging limits. Use the exact UK model and model year because specifications and menu paths can change.
COMMON QUESTIONS
Frequently asked questions
How long does a 7 kW charger take?
Divide the battery energy being added by 7, then allow extra time for charging losses and power variations. Adding 35 kWh takes approximately five hours plus losses.
Why is my EV charging below the charger's advertised speed?
The car, battery temperature, state of charge, shared charger load, cable or supply can limit power. Rapid charging also deliberately slows as the battery fills.
Can I charge an EV from a three-pin socket?
Some manufacturers supply equipment for this, but it is slow and should not be assumed suitable as a permanent solution. Follow the car and charging-equipment instructions and have the electrical installation assessed where necessary.
SOURCES & FURTHER READING
Check the current guidance
Rules, grants, tariffs and prices can change. Follow the linked source before making a financial or installation decision.