Every EV charger, from the granny cable in your boot to a 22kW wallbox on your driveway, does the same basic job: it takes AC electricity from the grid and gets it into your car’s battery as DC. The bit that actually converts it, the onboard charger, lives inside the car itself, and it’s the single biggest reason two chargers with different power ratings can charge the exact same car at wildly different speeds. That one fact explains most of what confuses people when they first start looking into home charging.
This guide walks through what’s actually happening every time you plug in, why charging speed varies so much between setups, what the different cable and power options actually mean in practice, and what getting a charger installed at home involves from start to finish.
So what actually happens when I plug my car in?
Electricity from your home’s supply, or from a public charge point, arrives as AC, alternating current. Your car’s battery, though, can only store DC, direct current. Sitting between the two is a component called the onboard charger, built into the car itself, and its job is converting that AC into DC at whatever rate it’s designed to handle.
This is the part most people don’t expect. The wallbox on your wall isn’t actually “charging” your car in the way it sounds like it is. It’s really just safely delivering AC power at a certain rate, and your car’s own onboard charger decides how much of it to actually convert and pass to the battery. That’s why a 7kW charger and a car with a 7kW onboard charger is a perfectly matched pair, but plugging that same car into a 22kW charger won’t get you 22kW of charging. The car simply can’t accept more than its onboard charger allows.
Rapid and ultra rapid public chargers work differently. They skip the car’s onboard charger entirely and deliver DC directly to the battery, which is how they manage speeds a home charger physically can’t. Our guide to the different types of EV charging breaks down AC versus DC charging in a lot more depth if you want the fuller picture.
Why does charging speed vary so much between chargers?
Three things determine it: the charger’s power rating, your car’s onboard charger limit, and (for some cars) the phase supply available at your property. A 3kW charger, a 7kW charger and a 22kW charger are the three common home and workplace ratings in the UK, and each one delivers roughly that amount of power per hour, assuming your car can actually accept it.
In practice, most single vehicle households end up choosing 7kW, since it’s the fastest speed most single phase domestic electrics can support and it suits the vast majority of cars on sale. Our comparison of 3kW versus 7kW versus 22kW home chargers goes through exactly which one makes sense depending on your car, your electrics, and how you actually drive.
What’s actually different between the charger unit and the cable?
The wallbox itself is the charger, it’s wired into your consumer unit, it handles the safety side, and it delivers power at its rated speed. The cable is just the physical connection between that unit and your car. Some chargers come tethered, with the cable permanently attached, others are untethered, meaning you connect your own separate Type 2 cable each time.
Neither is better in every situation, it genuinely depends on your setup. Our full breakdown of tethered versus untethered EV chargers covers which suits a typical single vehicle household versus a multi vehicle one, and our guide to EV charging cables explains the cable specifications themselves, lengths, ratings, and what actually matters when you’re buying one separately.
Can I just charge from a normal three pin socket at home?
Technically, yes, using what’s called a granny charger, the basic cable that comes with most EVs. It’s genuinely useful for occasional or emergency top ups, but it’s not designed for daily use. It draws a continuous 10 amp load from a socket and circuit built for intermittent use, which over months of nightly charging creates real wear at the socket contacts.
Our guides on what a granny charger actually is and specifically what a granny EV charger involves cover when it’s genuinely fine to use and when it isn’t. If you’re weighing up home charging generally, our full guide on how to charge an electric car at home is worth reading end to end before you commit to anything.
Is a granny charger actually a fire risk if I use it every night?
It’s a fair question, and the honest answer is that the risk comes from the setup, not the EV technology itself. A dedicated wallbox on its own 32A circuit, correctly installed, removes the fire risk that comes with running a domestic socket at near maximum load every single night. Our detailed look at EV charger installation and fire risk covers exactly what the data shows, what causes charging related fires when they do happen, and why a properly installed wallbox is considered as safe as any other major domestic appliance.
What’s a smart charger, and does it actually matter?
Every new home charger sold in the UK has to be smart compliant under government regulations, but what that actually gets you is worth understanding properly. A smart charger can schedule charging for cheaper off peak electricity rates, talk to smart tariffs, and in more advanced setups, support vehicle to grid technology, where your car’s battery can actually feed power back into your home or the grid when it isn’t being driven.
Our guide to smart EV chargers and V2G explains how that works in practice and which cars and chargers currently support it, since it’s still a developing area rather than something every setup can use yet.
Can I charge directly from solar panels?
Sort of, and it’s a genuinely popular setup. A smart charger paired with a solar diverter can prioritise using your own generated solar power to charge the car before pulling anything from the grid, which can meaningfully cut running costs if you’ve already got panels installed, or are considering them alongside a charger. Our guide to solar powered EV charging covers how that setup actually works and what it takes to get the two systems talking to each other properly.
What’s actually involved in getting a home charger installed?
It starts with an electrical assessment, checking your consumer unit’s capacity, your incoming supply, and the route the cable will take from consumer unit to charging point. Our home EV charger installation page covers the full process, and if you want to understand your electrics before booking anything, our guide to preparing your home’s electrical system for an EV charger is a genuinely useful read first.
Most straightforward domestic installs are done in a single visit. Our page on how long EV charger installation actually takes sets realistic expectations depending on your property and whether anything unusual comes up during the survey. And if you’re wondering whether you’re even allowed to have one installed, our guide on who can actually have an EV charger installed covers driveway, off street parking and other requirements.
Whoever does the work, it matters that they’re properly qualified. Our guide to finding a certified EV charger installer explains exactly what credentials to check before booking anyone, and why that documentation matters for both safety and insurance down the line.
What does it actually cost, installation and running?
Installation cost depends on your property, the charger you choose, and how much electrical work is needed to get power to the right spot. Our full breakdown of how much EV charger installation costs in the UK and our separate page specifically on installation labour costs both go through what drives the variation between quotes, and our general EV charger installation cost page gives the fuller overview.
There’s also help available to bring that cost down. Our guide to EV charger installation grants in the UK covers what’s currently available and who qualifies, and if you’re VAT registered or installing through a business, our page on VAT on EV charger installation and our guide to tax relief for UK businesses are both worth reading. Running costs, meanwhile, come down mostly to your electricity tariff and how much of your charging happens on off peak rates, which is exactly where a smart charger earns its keep.
It’s also worth checking how a charger affects your home insurance before installation, not after. Our page on EV chargers and home insurance covers what to expect and what to tell your insurer once the work’s done.
What if I live in a flat or a rented property?
This is genuinely one of the more common questions we get, and the honest answer is that it’s more complicated than a driveway install, but far from impossible. Shared or communal parking usually means an untethered charger and, often, permission from a landlord, freeholder or management company before any work starts. Our guide to EV charger installation for flats and rented properties covers the realistic options and what to expect from that process.
Is charging any different for new build homes?
New builds actually have it easier in one specific way: UK building regulations now require most new homes to have EV charging infrastructure built in from the start, which can simplify the installation considerably compared with retrofitting an older property. Our guide for EV charger installation on new build homes and for developers covers what’s typically already in place and what still needs specifying.
What about charging at work, or on commercial premises?
Workplace charging works on the same underlying principles as home charging, AC power, an onboard charger converting it, and speed depending on both the charger and the vehicle, but the scale and management side is usually more involved. Our guide to workplace EV charger installation covers what that typically looks like, and our broader commercial EV charger installation guide, along with our page specifically on commercial installation in London, cover fleet and multi unit setups in more depth.
Which charger models are actually worth knowing about?
A handful of models come up again and again for good reason. The Ohme ePod is well known for its smart tariff integration, particularly with Octopus Intelligent. The Andersen Quartz is a design led option that suits driveway installs where appearance matters as much as function. And the Tesla Wall Connector uses a standard UK Type 2 connector and works with any Type 2 vehicle, not just Teslas. Our full chargers page has the wider range we install if you want to compare more than just these three.
“Do hybrid cars charge the same way as full EVs?”
Plug in hybrids, yes, broadly, they use the same AC charging principles as full EVs, just with a smaller battery that charges faster relative to its size. Self charging hybrids are a genuinely different thing though, and don’t plug in at all. Our guide on what a self charging hybrid car actually is clears up that confusion, since the name itself trips a lot of people up.
Where We Install
We install home, workplace and commercial EV chargers across Barnet, Croydon, Ealing, Richmond upon Thames, Watford, Westminster, Waltham Forest, Wandsworth, Tower Hamlets, Sutton and Brent. Our full locations page covers the wider coverage area beyond these if you’re not sure whether we reach you.
How Do EV Chargers Work FAQs
Does a more powerful charger always mean faster charging?
Not necessarily. Your EV’s onboard charger sets the maximum rate it can accept from an AC home charger. For example, a 22kW charger will not charge a car with a 7kW onboard charger any faster than a 7kW charger, because the vehicle limits the charging rate.
Do I need a three phase electricity supply for a fast home charger?
Most UK homes have a single-phase electricity supply, which can support home charging at around 7kW. Faster AC charging above this level generally requires a three-phase supply, which is less common in domestic properties and may require an electrical supply upgrade.
How long does it actually take to fully charge an EV at home?
Charging time depends on the size of your EV’s battery, its onboard charger and the power available from your home charger. A 7kW charger can typically take around six to twelve hours to fully charge a typical family-sized EV, making overnight charging practical for many drivers.
Is it cheaper to charge at home than at a public charger?
Generally, home charging can be considerably cheaper than using public rapid chargers, particularly when you use an off-peak or EV-specific electricity tariff. Public rapid charging typically costs more because you are paying for faster charging and the infrastructure behind it.
Can I install a charger myself to save money?
EV charger installation involves electrical work that should be carried out by a suitably qualified and competent electrician. The installation also needs to meet relevant electrical and building regulations requirements, with notification or certification required where applicable. Using a qualified installer helps ensure the charger and its dedicated circuit are installed and tested correctly.
Do all EVs use the same charging connector?
For AC home charging in the UK, Type 2 is the standard connector used by virtually all modern EVs. For rapid DC charging, CCS is widely used, while some older or specific vehicles use CHAdeMO. For most home charging installations, Type 2 is the connector you will encounter.
Does cold weather affect home charging speed?
It can. Very cold batteries may charge more slowly because the vehicle’s battery management system regulates charging to protect the battery. The effect can be more noticeable during rapid DC charging, while the impact on normal AC home charging is often less significant.
Can I charge two EVs from one home charger?
A single charge point cannot normally charge two vehicles simultaneously. If you have two EVs, you can either charge them at different times or install a second charger. Some smart charging systems can also support load sharing between multiple chargers so the available electrical capacity is managed safely.
Will a home charger work if I don’t have off street parking?
A standard wall-mounted home charger requires a safe way to connect your vehicle without creating a hazard for pedestrians or other road users. If you do not have off-street parking, options may depend on your property, cable routing and local council requirements. Your installer can assess the site and explain what installation options may be available.
Do I need to tell my energy supplier I’m installing a charger?
Your installer can handle the required notification to your electricity network operator where applicable. This is separate from your electricity supplier. You may also want to contact your supplier if you are considering an EV-specific tariff designed to offer cheaper electricity during certain off-peak periods.
What happens if my car’s onboard charger is slower than my wallbox?
The car simply draws power at the maximum rate its onboard charger allows. A more powerful wallbox will not force the vehicle to charge faster than its own limit, and using a higher-rated charger does not normally damage the vehicle. It can also give you more flexibility if you change to a vehicle with a higher charging capacity later.
Is DC rapid charging bad for my battery if I use it often?
Frequent rapid charging may contribute to faster battery degradation over the long term compared with predominantly using AC charging, although modern EV battery management systems are designed to manage rapid charging safely. Where practical, many drivers use home AC charging as their regular charging method and rapid charging mainly for longer journeys.
Can I get a smart charger installed even if I don’t have a smart meter?
Yes. A smart EV charger and a smart electricity meter are separate technologies. A smart charger can use its own connectivity for features such as scheduling and monitoring. A smart meter can still be useful if you want to use an EV-specific electricity tariff with time-of-use pricing.
Does installing a home charger add value to my property?
A home EV charger can be a useful selling point for buyers who already own an electric vehicle or are considering switching to one. Its effect on property value is difficult to quantify, however, and will depend on the property, location and buyer demand. It is best viewed primarily as a practical convenience and feature for EV owners.
What’s the very first step if I’m completely new to this and just want a charger installed?
The best first step is a proper site survey. An installer can assess your existing electrics, discuss charger options and power ratings that suit your vehicle, check the proposed installation location and provide a quote based on your property rather than a generic estimate.
Ready to Get Started?
Whether you’re installing your first home charger, upgrading an old one, or setting up charging for a workplace or new development, we can talk you through the right option for your situation. See our full services page, check our FAQs, or learn more about us. To get started, request a quote or contact us to arrange a no obligation site survey.
