How EV Fast Charging Works

Electric vehicles may be the future, but they aren’t the most popular vehicles on the market today by a long shot. Buyers have dozens of reasons for being leery of EVs, some of which are legitimate, and some are not rooted in reality. Two concerns that go hand in hand are range anxiety and long charging times, and while range is becoming less of an issue as new vehicles come to market, charging still takes too long in many cases.

This is where fast charging, or DC fast charging, comes in. With a vehicle capable of handling them, fast chargers can return as much as 80 percent of range within a half an hour or less, in some cases. Those are impressive numbers, but it is important to understand the basics of fast charging and how it works with today’s electric vehicles.

What Is Fast Charging?

Batteries need direct current, or DC, to both charge and discharge, but your local power grid operates using alternating current, or AC. This means that the AC must be converted to DC so that the battery can be charged, which requires a converter, either onboard the vehicle or in the charger itself. To increase the speed of conversion, and subsequently charging, the charging and converter components must be larger and heavier. While many vehicles have small onboard chargers that perform the power conversion, increasing the size of in-vehicle components make it heavier and more complex.

DC fast charging, also referred to as Level 3 charging, takes care of these problems. In EVs that are capable of using the technology, fast chargers bypass the onboard charger and send power to the battery directly. The rate of charging can reach 15 times that of other chargers, and in some cases can add as much as 75 percent or more of battery capacity in as little as 30 minutes. DC fast chargers are large and expensive, however, and are not practical or possible for most EV buyers, even if they have room for one. Some units can cost $50,000 or more, which is why they are mostly reserved for public charging stations.

Charging Levels Explained

Level 1

Level 1 charging utilizes standard household outlets and is only capable of providing around five miles of range per hour. Most drivers find this method of charging far too slow to be practical for everyday use, and only consider it as a backup for when more powerful charging is not available. Level 1 charging also is not used in many global markets, because 220V is the standard in several countries.

Level 2

Level 2 chargers handle voltages in excess of 200 volts and can charge many EVs at a much higher mileage rate than Level 1. In general, a vehicle being charged at Level 2 will regain 20 to 60 miles of range per hour.

Level 3

Level 3 charging is considered DC fast charging or fast charging. Since it uses much higher voltages and requires a larger footprint than Level 2 charging, Level 3 charging is reserved primarily for public charging stations and those installed at commercial properties. The upside to fast charging is that it can recharge a capable EV to 80 percent or more in a half hour or so.

Is It Worth Installing a Level 2 Charger at Home?

If you own an electric vehicle and expect to do any charging at home, a Level 2 charger should be at or near the top of your to-do list. Charging with a standard 120V household outlet can take days to charge a modern EV with ranges of 300 miles or more. Consider this: At the typical household charging rate of four to five miles of range per hour, it could take you over two days to charge a Tesla Model 3 with a battery that is nearly empty. Moving to a Level 2 charger can cut that time by 80 percent or more, as some EVs can charge at up to 50 or 60 miles of range per hour.

How Much Does Installing a Level 2 Charger Cost?

The cost of installing a Level 2 charger at home will vary, depending on the location and on the existing electrical situation. If the garage or charging area has existing wiring or an existing 240V outlet, installation may be less expensive. On average, though, homeowners pay around $1,200 to have the charging system installed. Multiple-vehicle chargers and specialty installations cost more.


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