We all know roughly how long it takes to fill up at the gas station, and wherever we are in the world the process is almost identical. But this is not true with electric cars.
To answer what seems like a simple question, you need to factor in a lot of variables – some of which are obvious, like how much you want to fill the battery, and some are more obscure, like the type of onboard charger your car has.
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There are also differences from one country to another, with a range of different plug standards and voltage variations. For this article we will stick to electric car charging in the US, where 120-volt, 15-amp outlets are the domestic standard.
Can you charge an electric car from a wall outlet at home?
Charging from a wall socket can take 24 hoursiStock
Yes, you can. Electric cars come with an adapter for plugging their charge cable into a standard domestic wall outlet. But, while that outlet is great for powering all manner of domestic appliances, even powerful ones like ovens and dryers, it isn't much use for most electric cars.
Plug something like a Tesla into your kitchen outlet and a near-empty battery will take over 24 hours to fill up. While this is impractical in most cases, plugging into a domestic AC socket can add a couple dozen miles of range overnight, which can be useful if visiting family in a rural location with no public EV chargers nearby.
If you plan to buy an electric car, you should absolutely look at installing a dedicated EV charger at your home. This unfortunately isn't an option for those who live in apartments, or who don't have off-street parking. But if you have a garage and/or driveway, you have the space to install a so-called Level 2 charger.
How fast is a Level 2 home EV charger?
Home wall box chargers cost between around $200 and $600JuiceBox
Known as wall box charges, these use a 240-volt, 40-amp supply and have the same type of connection as the public chargers we will cover later. These AC chargers typically supply 7kW (kilowatts) of power, although some offer 9.6kW or even 22kW, but the latter will likely require a three-phase power supply instead of the more common one-phase supply found in most homes. Upgrading to three-phase is very expensive and not really worthwhile, since 7kW is enough to fill most electric cars overnight.
And remember, you are very unlikely to return home with a near-empty battery, just like how you don't come home each night with an empty gas tank. More often than not, your electric car will only need a partial recharge each night, which a 7kW charger is more than capable of delivering in a few hours. In this sense, your car is plugged in and charged at night in the same way your smartphone is.
Also, electricity is usually cheaper at night, so filling your car then is more cost-effective than during the day when energy is more in demand, and therefore more expensive.
These home charges tend to cost in the region of $200 to $600, depending on speed, features, cable length and design. They are all designed to work outside and are therefore safe to use in bad weather.
As for charge time, this will vary depending on the size of the battery and how full it already is. As a general guide, a 7kW charger will provide between 20 and 30 miles of range per hour, meaning roughly 200 miles from an eight-hour overnight charge.
How fast are public chargers?
Public chargers on a city sidewalkiStock
Public chargers are springing up all over the place, and are often located in parking lots at shopping malls, cinemas, hotels, restaurants and other places where you park for an extended period of time. There are also dedicated charging stations run by a wide range of companies, each offering various charging speeds at a range of prices.
EV chargers found in parking lots and on the street tend to be slower than those at dedicated charge stations. Some street chargers offer the same 7kW speed as home wall boxes, while others work at 20 to 50kW.
A quick note on kW and kWh: the former is the speed of a charger and the latter is the capacity of an electric car's battery.
Chargers operating at 50kW are a great option for a quick top-up, as they can mostly fill a Tesla in a couple of hours or so. But remember, you will rarely (if ever) need to refill a battery from zero to 100 percent; you are more likely to plug in while doing your weekly grocery shop, or while out for lunch, and in that time the car will recharge from, say, 20 to 80 percent.
As a rough guide, a 22kW charger should deliver up to 90 miles of range per hour, and for 50kW charger that range will be achieved in 30 minutes (unless the battery is already quite full, in which case it will be slower).
Level 3 DC chargers
Next up we have the fastest of public chargers, known as Level 3 DC rapid chargers. Usually located near highways or at pre-existing service and gas stations, these have a charge rate of 100kW or more, and in some cases can supply power at 250kW or even 350kW.
Such power can add range to your EV at a rate of over 1,000 miles per hour, filling even the biggest batteries from almost empty to over 80 percent full in around 20 minutes.
Remember, an empty battery charges much more quickly than one that is almost full, so that 1,000 mph rate will only be sustained briefly by an almost-empty battery, before gradually slowing as the battery fills. As such, it is often not worth your time charging the last 10 or 20 percent of an EV battery – and why manufacturers often quote 0-80 percent refill times.
The Electrify America charging network offers speeds of up to 350kW at its charging stations located near highways, where rapid charging is most needed. The company offers 50-150kW charging at its stations located in metropolitan areas.
Tesla's Supercharger network, which is for the exclusive use of Tesla vehicles, can charge at up to 250kW using the company's newest V3 chargers. Tesla also has a broad network of so-called destination chargers, which are slower and designed for use at hotels and other places you park at for an extended time.
The fastest and most convenient chargers (in other words, a 350kW charger next to a highway) tend to be the most expensive, while slower public chargers in metropolitan areas are cheaper and sometimes free to use.
What rate is your car capable of charging at?
As well as the power of the charger, how quickly the battery fills is restricted by the car itself, and the capabilities of its own charging hardware. For example, when connected to a rapid DC charger, the Porsche Taycan can charge at up to 270kW using its high-end 800-volt architecture, while the Chevrolet Bolt is limited to a charge rate of 50kW.
The Bolt can still use any home or public charger, but it will only refill at a rate of 50kW, no matter what the charger is capable of.
AC or DC?
The Volkswagen ID4 charges at up to 125kWVolkswagen
Not a rock tribute band, this question refers to how AC and DC car chargers differ. Home chargers and less powerful public chargers use AC (alternating current), while fast and rapid public chargers use DC (direct current).
Electric cars have an onboard AC charger to accept power from an AC connection, but this is often limited to a fairly low charge rate. Looking at the upcoming Volkswagen ID4 as an example; this car's onboard AC charger has a maximum acceptance rate of 11kW – an AC figure shared with many others, including the Taycan.
But when attached to a DC rapid charger, the Volkswagen can accept a charge rate of up to 125kW.
As we said at the top of this article, the topic of electric car charging is complicated. To keep things simple, you need to remember these key points:
- Plugging into a domestic wall socket can help in emergencies
- Using a home 7kW charger at night makes most sense
- Empty batteries charge fastest
- Charging above 80 percent takes an increasingly long time
- Understand the maximum AC and DC charge rates of your car, usually 11kW for the former
- Research where your local public chargers are, especially the fastest DC charger your car can handle
- Look up the fastest compatible public chargers when going on a longer journey