Electric vehicle charging: Systems, levels, and connectors explained

Do you know your AC from your DC? How about level 1 from level 3? In the world of EVs, knowing the difference between hardware and electrical standards could mean the difference between a one-hour charge and an overnight one…

If you’re new to the world of electric vehicles, or you’re just doing some early research, you’ve probably got a bunch of questions about the basics. And that’s totally understandable! While none of the associated tech is particularly complicated in practice, learning and internalizing any new terms and tech standards can be a daunting task.  

After all, if we went back in time to 2006 and handed you an iPhone 14, you’d probably have a ton of questions about how to use it. EV charging is exactly the same for newcomers, which is why we’ve put together this piece exploring some of the most common questions people have on the subject.  

So, if you’re confused about what kind of charger type does what, or you can’t tell your trickles from your DCs, worry not! We’ve got you covered…

What are the three types of EV charging systems?

We’ll move on to the various types of physical chargers you can expect to come across in a bit, but first we need to cover a pretty fundamental topic in the world of electric vehicle charging: the systems through which you’ll deliver charge to your car.  

There are three types – or levels – of charging, depending on the infrastructure you connect your EV to. The higher the level, the faster your car will charge, and the more efficient your charging experience will be.

Level 1: “Trickle” charging

Trickle charging is the slowest and least efficient EV charging system, but it’s also the only one that doesn’t require any kind of extra infrastructure. That’s because level 1 charging is achieved by simply connecting your car to one of your home’s standard mains plugs.

Trickle charging will net you up to around 15 miles of range per hour, but it can be much slower depending on the car. Because of that, this method takes a pretty long time to fully charge an EV and is best reserved for emergencies (or hybrid vehicles with smaller batteries). Besides this, using your standard mains plugs to charge an EV can have knock-on effects on your house’s energy usage and costs.  

In other words? Trickle charging should only really be a last resort.  

Level 2: AC charging

AC charging takes an alternating current, like the kind your house receives from the grid, and ups the voltage (from 120 to around 230) to deliver a faster charge. At home, you’ll achieve this by installing a dedicated AC wall box charger, which can fully charge a car with a 40 kWh battery in around six hours.

When you’re out and about, the majority of the public chargers you’ll come across right now will probably be AC (level 2) ones. AC public charging is usually a lot quicker than charging at home because the infrastructure is built to supply a higher voltage than most homes and home wall boxes.  

Level 3: DC charging

Level 3 charging is the fastest by far. What sets DC charging apart is how the charge boxes deal with the electrical current.  

As a quick science lesson: electricity is normally distributed in the AC (alternating current) standard because its wave-like form helps it travel further. At the point of being transferred to a device’s battery, most devices – including everything from your laptop to your EV – must then convert the current to DC in order to maximize the energy transfer. With electric vehicles, that means having an AC to DV converter built into the car – often called an ‘onboard charger’.  

Ultimately though, the main thing you need to know is that public DC chargers have that converter built right into the box, enabling them to switch the current at the source instead of in your car. That results in much faster charging at around 50 kWh and 450V – though some DC chargers can reach 900V – that can fully charge an EV in around an hour.

What are amps, volts, and watts?

Here’s a little refresher on the units of measurement you’ll commonly run into in the EV charging world:

What are Amps?  

‘Amps’ is short for ‘amperes’, which is the unit for measuring the amount of electric current being used. They’re named after French physicist André-Marie Ampère, who was a fundamental founder of modern electrical science.

What are Volts?  

Volts are the force of the electricity flow – think of voltage in the same way we talk about the bandwidth of your broadband cable, or the flow of the water coming out of your faucets. The more voltage, the higher the force you can exert.

What are Watts?  

Wattage is a measurement describing the delivery of energy in a given period, similar to horsepower in an engine. When we exceed 1000 watts we start using Kilowatts, which are what you’ll normally encounter with EV charging.

The three terms are closely related in that wattage is the sum of ‘amps x volts’. Or, in other words: the amount x the force = the total ‘workload’.

What’s the difference between level 1 and level 2 charging?

At home, the difference between level 1 and level 2 charging is all about hardware. The addition of a wall box charging unit – like the ones Spirii-certified hardware partners provide, enables EV owners to pump higher voltages through their mains and into their cars.  

When out and about, you won’t find level 1 charging as an option. Instead, you’ll either find level 2 (AC) or level 3 (DC) options. As discussed, level 2 charging is the slower of the two, but it’s still much faster than trickle charging using a standard plug socket at home.

What’s the difference between AC and DC charging?

It all boils down to where the current is converted. As mentioned, most electric vehicles have an onboard converter for changing the electric current from AC to DC. The problem is that doing that requires time and energy, which results in a reduction in charging efficiency.  

DC chargers, then, offer some pretty serious speed gains. When you connect your car to a DC charger, it supplies converted DC power directly to your car battery.  

A good way to think of it is to compare it to the protein in food. Here, AC chargers are the equivalent of eating a bunch of meat and waiting for your body to extract the protein. On the other hand, DC chargers are more like drinking a protein shake – you’re going to get a more concentrated blast of the good stuff much more quickly.  

The only real downside is that DC’s faster, more powerful charging can come at a higher cost to the end user, as well as in terms of upfront hardware costs for the charge point operator. It’s also wise to mix up your use of AC and DC charging, since DC (fast) charging can put a bit more strain on your car’s battery, and can reduce its overall lifespan as a result.

Something to remember…

Level 1 and level 2 (AC) charging types typically deliver electricity to car batteries consistently over most of the length of the charge. DC charging is different; it will front-load most of the power delivery before tailing off. That’s to enable cars to get the energy they need for most journeys quickly. As a result, filling up from 80-100% will take longer than any other 20% stretch.

Can any EV use DC charging?

In everyday use, DC chargers don’t differ from AC ones – it’s the same process of connecting your car, charging up, and making a payment.  

A small minority of (mostly older) electric vehicles aren’t compatible with DC chargers due to the specific connector type. However, with DC charging becoming more mainstream, there’s been a movement to standardize charging cables so as to allow any type of car to use any type of charger – AC or DC.

One exception to this in some markets is the Tesla-branded Supercharger. While these chargers do use the more modern CCS connector (more on that in the next section), they have traditionally been software-locked to Tesla cars. At the time of writing, though, Tesla is in the process of opening these chargers up to all EV drivers in select markets.

What are the different EV charger types?

Ok, let’s talk connectors. As with all things EV, it’s one of those things that seems a lot more complicated at first than it really is – so let’s cover the key connector types and dig into what the differences really mean.

AC connector types

Type 1 and Type 2 (J1772) connector  

Type 1 connectors are slightly old by today’s standards. They allow for home or public level 2 AC charging at up to 7kW – or slightly up to 22kW if your car supports rapid AC charging.  

DC connectors

Combined Charging System (CCS1 in the US, CCS2 in Europe)

If you buy an EV today in either the US or Europe, it’s likely to have one of the two standardized CCS connector types. This combined design allows for AC or DC charging – it’s effectively the traditional J1772 with a couple of DC pins underneath.  

Tesla Supercharger

In the US, Teslas have traditionally worked with a proprietary Supercharger connector, but since the EU is able to be tighter on limiting proprietary formats, European Teslas ship with CCS2 connectors. US Tesla owners, meanwhile, can buy a cable adapter for CCS1 compatibility.  


The CHAdeMO standard is big in Japan, but it’s not that common outside of the Asian market aside from use in the Nissan Leaf. It enables DC fast charging, but it actually requires a separate J1772 cable to be plugged in at the same time.

Which EV has the best charging system?

When you’re buying anything new, it’s totally natural to want to be sure that you have the best, most future-proof option there is. If you were in the market for a TV right now, for instance, you’d probably want to be sure you knew your HD from your 4K, and that the one you buy is going to work well for a number of years.  

Buying an EV is no different, but the good news here is that – while battery technology will continue to evolve – pretty much any new electric vehicle you buy today is going to be set up for fast charging for the foreseeable future.

That’s because the connector types that enable AC and DC have now largely been standardized to the CCS1 and CCS2 types in all modern passenger EVs, which allow for either kind of charging.

Ultimately, that means that the best charging system for your car will be the one you have access to when you need it. If an AC charger is available where you are, great. If a DC one is available, even better! If you have a modern electric car you’re likely to be able to connect to either.  

With DC being the faster technology, though, you’ll probably see more and more public DC chargers – with higher and higher kWh and voltage outputs – as the transition to electric vehicles evolves and matures.  

All of which means one thing: while it’s great to know what terms like AC, DC, and levels 1/2/3 mean, driving and charging an electric vehicle are only set to become more and more simple – and jargon-free – activities as time goes on.

What about the software side of things?

We’ve talked a whole lot in this piece about charging hardware, but what about the software? If you’re interested to learn about the tech that underpins today’s eMobility networks, we’ve got an in-depth guide to EV software right here.  

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