How does public electric car charging actually work?
What happens between arriving at a charger and driving away, why speed depends on your car as much as the charger, and the practical etiquette that keeps the queue moving.
- Difficulty
- beginner
- Time
- 20 min
- Read
- 5 min
- Safety
- caution
Short answer
Most public chargers now take contactless payment by law for new rapid units, though many still work best through an app or an RFID card, so carry at least one account as a backup. Charging speed is limited by whichever is lower — the charger's output or your car's maximum acceptance rate — and it slows down sharply above about 80 per cent, which is why rapid charging stops are usually short rather than full.
Public charging has a reputation for complexity that is only half deserved. The mechanics are simple: plug in, authorise payment, wait, unplug. What makes it feel complicated is the fragmentation — several networks, several apps, several payment methods, and a charging speed that depends on factors most drivers have not been told about. Once you understand that the car and the charger negotiate a rate together, and that the battery's state of charge changes that rate as it fills, almost everything else about public charging makes sense.
Safety
Step by step
- Plan around chargers rather than hoping.A mapping app that shows live availability and reported faults is the single most useful tool, and most also let you filter by connector and speed. Plan a primary stop and a fallback, particularly on an unfamiliar route.
- Understand the two families of charging.AC charging goes through your car's onboard charger and is limited by that unit — typically 7 kW at home and up to 22 kW at some public posts. DC rapid charging bypasses it and feeds the battery directly, which is why it is far faster. Destination car parks and on-street posts are usually AC; motorway services are usually DC.
- Check what your own car can accept.This is the number people miss. A car with a 50 kW maximum will charge at 50 kW on a 350 kW charger, and paying for the faster unit gains nothing. Similarly, a car with a 7 kW onboard charger will not go faster on a 22 kW AC post.
- Arrive with the battery reasonably low if you are rapid charging.Charging is fastest at low states of charge and slows markedly as the battery fills, typically tapering above around 80 per cent. Two shorter stops from low to 80 per cent are usually quicker overall than one long stop to 100 per cent.
- Sort out payment before you need it.Regulations now require contactless card payment on new rapid chargepoints, and it is increasingly available on older ones, but coverage is uneven. Having one or two network apps set up with a payment method saved, plus an RFID card if your usual network offers one, removes almost all of the stress.
- Precondition the battery if your car offers it.Many EVs will warm the battery on the way to a charger you have set as a destination in the built-in navigation. A cold battery accepts charge much more slowly, so this can halve a winter charging stop. It usually only works through the car's own navigation, not through a phone app.
- Plug in, authorise, and check it has actually started.Seat the connector fully — most lock automatically. Then check the unit's screen or your app shows a session running and a sensible power figure. Walking away from a session that never started is the most common wasted stop.
- Move the car when you are done.Charging bays are for charging, and many networks now apply overstay fees. On a busy rapid charger, taking the car to 100 per cent while others wait is the behaviour that gets people annoyed, because the last twenty per cent takes as long as the first sixty.
Common mistakes
- Relying on a single network app — Coverage is uneven and any one network can be unavailable at the place you stop. Two accounts and a contactless card cover almost every situation.
- Charging to 100 per cent at a rapid charger out of habit — The final stretch is the slowest part by a wide margin. It ties up a bay, costs more time than it saves, and on most journeys is unnecessary.
If it doesn't work
Charger will not start a session
Cause: Payment authorisation, a connector not fully seated, or a unit that needs resetting — Fix: Unplug, reseat firmly, and try again. If it fails twice, try the other connector or bay and report the fault through the network app — most have a phone number on the unit and can reset it remotely.
Charging much slower than expected
Cause: Cold battery, high state of charge, a shared unit, or your car's own limit — Fix: Check whether another car is plugged into the same unit, since many rapid chargers split their output between two bays. Then check your state of charge and the temperature, which explain most of the rest.
Connector will not release
Cause: Locking pin still engaged because the session has not ended cleanly — Fix: Stop the session properly in the app or on the unit, then unlock the car — most cars release the connector when unlocked. Handbooks describe a manual release for the rare case where it does not.
Bay blocked by a petrol car
Cause: Poor enforcement — Fix: Frustrating and common. Report it to the car park operator; many now enforce bay misuse. Having a fallback charger planned is the practical answer.
App says available but the unit is broken
Cause: Live data is not always accurate — Fix: Another argument for a fallback. Reporting the fault genuinely helps, because networks rely on driver reports to spot units that have failed without reporting it themselves.
Questions people ask
Do I have to use an app?
Increasingly not. Regulations require contactless payment on new rapid chargepoints and mandate 99 per cent reliability for rapid networks, which has improved things considerably. Older and slower units are more mixed, so an app or two remains the sensible backstop.
Is public charging more expensive than home charging?
Substantially, especially rapid charging, because it carries the cost of the infrastructure. Home charging on an off-peak tariff is the cheapest way to run an EV by a wide margin, which is why the home-charging question matters so much when deciding whether one suits you.
Do I need to bring my own cable?
For AC charging, usually yes — most AC posts are untethered and you use your own Type 2 cable. DC rapid chargers have their cables permanently attached, so you plug the unit's cable straight into the car.