What Is an EV Charger? A Beginner's Guide to Charging at Home and in Public

If you have just ordered your frst electric car, the charging side of it can feel like the part nobody explained properly. The brochure quotes one number, the charging app quotes another, and it is common to wonder why a 7 kW unit seems to be delivering half that.

An EV charger is, at its simplest, the box that sits between your electricity supply and your car and manages the safe transfer of power into the battery. That definition is accurate but not very useful, because almost everything people find confusing about charging happens inside that word "manages".

This guide covers what the equipment actually does, how EV charging works step by step, what differs between charging at home and charging in public, and where AC and DC part company. It is written for the UK, where the supply voltage, connectors and regulations differ from other markets.

What an EV charger actually is

The industry calls it electric vehicle supply equipment, or EVSE. You will also see chargepoint, charge point and charging station used interchangeably, and in the UK "home charger" or "wallbox" for the domestic version.

Here is the part that catches people out. On a home unit, the box on your wall is not really doing the charging. It is a very clever switch: it checks the connection is safe, talks to the car, and then passes mains electricity through to it. The actual conversion happens elsewhere.

Why the real charger is inside your car

A battery can only take direct current. The grid delivers alternating current. Something has to convert one to the other, and on a home unit that something is a component in the car called the on-board charger, or OBC.

This single fact explains most of the confusion further down this page — including why two cars plugged into identical chargers can fill at completely different rates.

How EV charging works, step by step

Plug in and the sequence is roughly this. The connector locks. The charger and the car exchange a short handshake over a control pilot signal, agreeing how much current the installation can safely supply and how much the car is willing to accept. Only once both sides agree does anything become live.

Power then flows, with the charger monitoring for faults — earth leakage, over-current, over-temperature — and cutting the supply if it sees one. When the battery reaches the target state of charge, or you stop the session, the flow stops and the connector unlocks.

Nothing in that cable is live until the handshake completes. It is also why charging in the rain is entirely safe, a question that comes up constantly.

AC and DC: the distinction that explains everything else

There are only two real families of charging, and once you have them straight the rest falls into place.

AC charging sends alternating current to the car and lets the car's on-board charger convert it. The equipment is small, cheap and simple, which is why it is what you get at home. The ceiling is the car's OBC.

DC charging does the conversion inside the charging unit and feeds direct current straight to the battery, bypassing the OBC entirely. That removes the ceiling, which is why motorway chargers can hit 150kW and beyond — but it also means a cabinet full of power electronics, which is why you do not find one on the side of a house.

The UK uses charging "modes",not "levels"

You may come across the terms Level 1, Level 2 and Level 3. These come from SAE J1772, the North American standard, and describe equipment for a 120/240 V system with connectors such as J1772 and NACS —which is not what a UK car and supply use.

Europe and the UK use IEC 61851, which sorts charging into four modes rather than levels:

Mode	What it is	Where you meet it
Mode 1	A plain socket, no EV-specific protection	Effectively obsolete for cars
Mode 2	A three-pin plug with a protection box built into the lead	The "granny cable" in your boot, around 2.3kW
Mode 3	Fixed AC charging over a dedicated Type 2 connection	Home wallboxes and most public AC posts, 3.7–22kW
Mode 4	DC fast charging with the conversion in the unit	Motorway and forecourt rapids, 50kW and up

Practically all UK domestic installations are Mode 3. When someone says "home charger", that is what they mean.

Home versus public charging: what actually differs

Around seven in ten EV drivers do most of their charging at home, and the reasons are less about speed than people assume.

	Home charging	Public charging
Typical speed	Slow — an overnight job	Fast — 20 minutes to an hour on a rapid
Cost shape	Money up front, then cheap per mile	Nothing up front, more per mile
Experience	Plug in, forget about it, wake up full	Finding a working unit and a free bay
Energy integration	Can be tied to a cheap overnight tariff or your own solar	Not possible

The gap in running cost is the real argument. GRIDSERVE, which operates one of the larger UK rapid networks, puts home charging at roughly 3p per mile against about 18p per mile on the public network — with petrol around 20p. That is a network operator being candid about its own product being the expensive option.

None of which means you need a driveway to run an EV. It does mean that if you have one, the sums change substantially.

Why your 7kW charger might only deliver 3.6kW

This is a common question from new owners, and it is almost never a fault. Three things cap your speed, and the lowest one wins.

Your car's on-board charger. If the OBC tops out at 7.4kW, an 11kW or 22kW wallbox will not move it any faster. Some earlier and cheaper models shipped with a 3.6kW OBC, and no amount of charger will change that.

Your electricity supply. Most UK homes have a single-phase 230 V supply. At 16 A that gives about 3.7kW; at 32 A, about 7.4kW. If your main fuse, meter tails or consumer unit will not support 32 A, your installer will commission the unit at 16 A.

Load management. A well-configured installation will pull power back when the oven, shower and kettle are all running, to keep the whole house inside the capacity of its main fuse. That is the system protecting you, not short-changing you.

Smart charging:why your charger is required to pause

Every domestic chargepoint sold in Great Britain since 30 June 2022 has to be "smart", under The Electric Vehicles (Smart Charge Points) Regulations 2021 (SI 2021/1467). This explains two behaviours that otherwise look like faults.

First, default charging hours. Regulation 10 requires the unit to arrive pre-set to charge outside peak hours, which the regulations define as 8am to 11am and 4pm to 10pm on weekdays. On first use you must be offered the choice to accept those hours, change them or remove them altogether. Plug in at six on a Tuesday evening without touching that setting and nothing will happen — by design.

Second, the randomised delay. Regulation 11 requires the charger to be capable of waiting a random interval of up to 600 seconds before starting, so that thousands of cars on the same cheap overnight tariff do not all switch on at 00:30 and hit the grid at once. You can cancel it for a given session, but out of the box, a pause of several minutes is normal.

Two limits are worth knowing. The regulations apply to England, Wales and Scotland — Northern Ireland has its own arrangements. And they exclude public chargepoints and rapid units of 50kW or more, which is why nothing on a motorway forecourt behaves this way.

What installation involves, and where the cost jumps

A straightforward installation is a few hours' work by a qualified electrician. The quotes that come in far higher usually do so for one of four reasons, all of which are worth asking about before you commit.

Distance is the common one: a charger on a detached garage may need armoured cable trenched from the consumer unit, and that can double a quote. Then there is supply capacity — if your main fuse or meter tails need upgrading, that is your distribution network operator's work, not your installer's, and it runs on their timetable rather than yours.

The third is the consumer unit itself, which may need additional protective devices or spare ways. The fourth is load management hardware, typically a current transformer clamp fitted near your meter so the charger can see total household demand. Installers are sometimes accused of upselling here; in a house with a modest main fuse it is genuinely the thing that lets you run at full power safely.

On grants, the current position is set out on GOV.UK. The Offce for Zero Emission Vehicles offers up to £500 towards a home chargepoint (increased from £350 on 1 April 2026)for renters, fat owners, and households with only on-street parking installing a cross-pavement solution. The schemes were extended for a fnal year and run until 31 March 2027. Owner-occupiers of a house with a private driveway are not eligible. Because the fgures and eligibility have changed recently, it is worth confrming the latest details on the GOV.UK chargepoint grants guidance before you apply.

Charging from your own solar: what has to be true

Anyone with panels on the roof arrives at the same reasonable question — can I just charge the car with those? The honest answer is yes, but only if three conditions hold, and none of them is automatic.

The first is that something must be able to see your surplus. Your solar generation and your household consumption both change minute to minute, and the only way to route what is genuinely spare into the car, rather than exporting it cheaply, is to measure the flow at the point where your supply meets the grid. That is a metering job, not a charger job.

The second is that the surplus has to be large enough to be useful. Charging cannot start below roughly 6 A, and on a 230 V single-phase supply that is about 1,380 W of spare generation. Below that threshold, a charger that tries to run will simply stop and start.

The third is that the charger has to follow the sun rather than fight it. A cloud passes, output halves, and a unit locked to one charging mode will drop out.

This is the specific problem the Zendure EVFlow AC series was built around. It is a Mode 3 wallbox in 7.4, 11 and 22kW versions, with Type 2 socket or five-metre tethered cable, and it works as part of a home energy management system rather than as an isolated load. On the 22kW unit it will hold off below 1,380 W of surplus, charge single-phase between roughly 1,380 W and 4,140 W, and step up to three-phase above that — so a partly cloudy afternoon produces continuous charging instead of a series of aborted attempts.

The same measurement underpins dynamic load balancing, which trims charging power when the rest of the house draws hard and restores it when demand falls. Worth being clear on one point: solar surplus charging, solar forecast charging and dynamic load balancing all depend on the separately available Zendure Smart Meter 3CT. They are not out-of-the-box behaviour, and any charger promising them without a meter is promising something it cannot see.

If your roof is not generating, the fallback is a cheap overnight window. The unit connects to live tariff data and charges below a price threshold you set, which is the same logic behind most practical approaches to reducing your electricity bill. 

On the safety side, the unit carries built-in residual current protection of AC 30 mA plus DC 6 mA, designed against IEC 62955 and IEC 61008. Your installation will still need an upstream Type A 30 mA RCD or equivalent; the integrated protection reduces configuration work rather than replacing it. Enclosure ratings are IP65 for the cable version and IP55 for the socket version, with IK10 impact resistance and an operating range of −30 °C to +50 °C, which is comfortably beyond anything a British winter will manage.

How to choose: three questions, in order

A useful way to start is with your house rather than with brands.

• What supply do you have? Single-phase means 7.4kW is your ceiling. Three-phase opens up 11 and 22kW. Checking the consumer unit is the quick test — three main breakers suggests three-phase, though your installer should confirm it.
• What can the car accept on AC? Look up the AC figure specifically, not the headline rapid-charging number. A car advertised at 150kW might well be limited to 7.4kW or 11kW on a home unit, because those are two entirely different paths into the battery.
• Tethered or untethered? This one generates more regret than any other, in both directions. A tethered unit is genuinely more convenient day to day — park, plug in, done — but you are committed to that cable and that length, and you will still want a loose Type 2 lead for untethered public posts. A socket version lets you choose your own cable and swap it later. If you already own a Type 2 cable, or one came with the car, the socket version is usually the better buy.

Frequently asked questions

Do I really need a home charger, or can I manage on public ones?

You can certainly manage. Plenty of drivers without off-street parking run EVs perfectly happily using on-street posts, workplace charging and destination chargers. What you give up is the cost advantage — public charging is several times the price per mile of a good overnight home tariff — and the convenience of never thinking about it. If you have somewhere to park off the road, a home unit typically pays for itself well within its life.

Can I install a rapid DC charger at home?

In practice, no. Rapid charging needs power-conversion equipment and a grid connection on a scale no domestic supply provides, which is why those units sit at motorway services rather than on driveways. It is also unnecessary: a car parked for ten hours overnight has no use for a charge that completes in twenty minutes, and slower AC charging is gentler on the battery.

Can I just use the three-pin plug that came with the car?

For occasional use, yes. The lead in your boot is Mode 2 equipment and delivers around 2.3kW, which is enough for perhaps 10 miles of range in an hour. It is not intended as your everyday method — a standard socket is not designed to carry near its full rated current for eight hours at a stretch, and extension leads should never be used for it. Have an electrician check the socket if you plan to rely on it at all.

Why doesn't my new charger start as soon as I plug in?

Almost always one of two legal requirements rather than a fault. The unit ships with default charging hours set outside peak times, so an evening plug-in may wait until later; and it applies a randomised delay of up to ten minutes before starting, to spread demand across the grid. Both are adjustable in the app, and both are covered above.

What extra equipment do I need to charge from solar panels?

A charger that supports solar surplus charging, and a meter or current transformer that can measure the flow between your home and the grid. Without that measurement there is no way to distinguish genuine surplus from power you are importing, so the charger cannot make the decision. If you also want the charger to back off when the rest of the house is drawing heavily, the same hardware provides that.

The short version

An EV charger is a safety and control device that connects your supply to your car. At home it passes AC to the car and lets the car convert it, which caps the speed at whatever the car's on-board charger allows. In public, rapid units convert to DC themselves and skip that limit.

For a first purchase, the sequence that avoids most regret is: confirm your phase supply, look up your car's AC limit rather than its rapid figure, then decide on the cable. Everything else — smart features, solar integration, tariff scheduling — sits on top of those three answers rather than substituting for them.