When shopping for a car, we all have different priorities. Some of us need to think about the number of seats its has, while others will be more preoccupied with in-car entertainment options, performance specifications or style.
For those picking an electric car, one of the primary concerns with any new car is how far it will travel per charge — but here at Transport Evolved we want to remind you that the speed and way in which your new car charges is just as important, because at some point during ownership of your new car, you’ll wish it could charge faster than it can.
Understanding the differences in charging
In general, the higher the number listed in your car’s specification sheet for charging, the quicker it will be able to replenish its battery pack. A car fitted with a 3.3 kilowatt on-board charger will take almost twice as long to charge as one with a 6.6 kilowatt on-board charger if both vehicles have an identical battery pack, for example. Similarly, a Tesla Model S, fitted with 130 kilowatt direct current (DC) Supercharger capability will be able to recharge its battery pack from an external rapid charge station faster than a Nissan LEAF charging at a 50 kilowatt DC CHAdeMO quick charge station.
But the most important thing to bear in mind here is that the first example we’ve given is based on a car’s on-board alternating current (AC) mains charging capability, while the second relies on an external DC charging station.
It’s common for both on-board AC charging capabilities and DC quick charging capabilities to be quoted on the vehicle specification sheets, so it’s important that you understand how each works.
AC slow/fast charging = home
For the most part, AC charging figures — with the exception of the Renault Zoe which we will come to later — relate to how fast you’ll be able to charge your car at home from a dedicated charging station or in public at a Type 2 or Level 2 public charging station.
Typically, you’ll find on-board AC charging power of an EV lies somewhere between 3 kilowatts and 10 kilowatts. (In the case of the Tesla Model S, you can even opt for up to 20 kilowatts of on-board charging capability in the U.S. and 22 kilowatts of on-board charging capability in Europe, but you’ll need a specially-deigned Tesla charging station to charge that quickly from a household power supply).
Many electric cars, like the Nissan LEAF and Tesla Model S, come with optional upgrades to their on-board charger. If you buy the base-model Nissan LEAF in many markets for example, your car will come with just a 3.3 kilowatt on-board charger — but you can pay extra for an upgrade to a 6.6 kilowatt on-board charger.
In the case of the Nissan LEAF, this turns the 6-8 hour recharge time from a domestic charging station to somewhere between 3 and 4 hours if you have a charging station capable of providing 6.6 kilowatts — but you should be aware that not all public charging stations or domestic charging stations can supply that kind of power. If you’re unsure, ask — otherwise you may find your car takes longer to charge than you expected.
DC (and AC) quick/rapid charging = on the road
While AC slow/fast charging is primarily for home, DC quick or rapid charging — and supercharging in the case of the Tesla Model S — is for use on the road when you need to refill your car’s battery pack quickly to make longer distance trips.
In quick charging situations, the cars rely on some form of external quick charging apparatus to quickly charge your car’s battery pack. With the exception of the Renault Zoe (see below) quick charging can only be performed at dedicated quick charging stations where power is channeled from off-board charging apparatus directly into the car’s battery pack, bypassing any on-board charging unit.
To do this, DC quick charging requires your car be fitted with a special DC quick charge socket. Normally, this will be a CHAdeMO quick charge, or Combo DC plug. In the case of the Tesla Model S — which uses the same connector for both AC slow and DC quick charging — you’ll need to get Supercharger capability turned on if you opt for the base-model 60 kWh Model S.
Importantly, quick charging capability is not related to the on-board charger you have in your vehicle. It’s possible, for example, to have a Nissan LEAF with a 3.3 kilowatt on-board charger and CHAdeMO quick charge capability, or a 6.6 kilowatt on-board charger and CHAdeMO quick charge capability. Despite having a more powerful on-board charger for charging at home, the second vehicle will charge just as quickly as the first at a quick charge station.
As for the Renault Zoe — the one we said had AC quick charging? That’s in a special league of its own. With a single chameleon charger fitted as standard to all Zoes, it’s possible to charge your car with anything from a 3 kilowatt domestic charging station to a dedicated 43 kW AC quick charge station with attached charging lead. Unlike DC quick charging cars, the Zoe actually turns AC power from the charging station into DC current to charge the battery on-board using its own power electronics. (If you’re thinking of buying a Renault Zoe — you can probably skip the rest of this article.)
Always buy the best charging you can afford
It’s worth noting that when it comes to DC quick charging, not all cars come with the capability fitted as standard. Many cars — like the Nissan LEAF and BMW i3 — are capable of DC quick charging, but you’ll have to specify the option at the point of ordering your car as you won’t be able to add it later. While it will add a little extra cost to your new car, it makes sense to always order an EV with quick charging capability because you never know when you’ll need to use it. Better still, as more and more quick charging stations are installed, the retail value of a car fitted with quick charge technology will always be more than one without, even if there are no DC quick chargers in your area.
In the same way, it’s always worth specifying the best on-board charging capabilities you can when ordering your car. While you may be buying an electric car with DC quick charge capabilities, a powerful on-board charger makes a massive difference when you’re left stranded by a malfunctioning charging station.
In fact, with 6.6 kW charging taking far less time than 3.3 kW charging, buying that charger upgrade can make the difference between making your destination an hour or so late and not arriving until the next day.
Essentially, our advice is pretty simple. Forget the leather trim, heated seats and fancy radio: if you’re strapped for cash and buying an electric car, always spend extra on charging in preference to other extras.
As for those other extras? They’re nice… but they won’t help you get out of a sticky charging situation quickly.
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