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DC Fast Charging

When your trip length is longer than your EV's range, you need to recharge while driving. In practice, this means recharging at a "DC Fast Charging Station". Since a regular public charging station will only give you about 20 miles of range per hour of charging, this usually won't be useful. A 50 kW DC Fast Charger will typically give you 140 miles of range per hour of charging, so a well timed lunch break will set up you up for the next leg of your trip.

The reason these fast charging stations are sometimes called "DC" stations is that they pump Direct Current (DC) electricity into your car instead of the Alternating Current (AC) that comes from the electric grid. Your car battery supplies and gets recharged using DC current. When you give it AC current via your EVSE or public charger, the car has an on board charger that converts the supplied AC to DC for the battery. That's why different EVs have different maximum kW or amp ratings for recharging via AC power: their on board charger has different capabilities.

So a DC charging station has a much larger AC to DC converter built into the charging station and feeds DC current directly into your battery bypassing your car's on board charger. This allow you to charge much faster.

Fast Charger Type Typical Power Range Added in 1 Hour
CHAdeMO 50 kW 140 miles
CCS 50 kW 140 miles
Tesla Urban Supercharger 72 kW 210 miles
Tesla Supercharger 120 kW 250-300 miles

There are three types of DC Fast Chargers in the US and Canada, but your EV will only support one of them (Tesla models S, X and 3 support two). However, most CHAdeMO and CCS stations have both both CHAdeMO and CCS handles.

CHAdeMO is supported by Japanese EVs and Teslas ( via an adapter), and the plug looks like this:

CCS is supported by European and domestic EVs (except Tesla):

Finally, the Tesla Supercharger is only supported by Tesla model S, X and 3 cars:

Regardless of which Fast Charging standard your car can support, you must make sure your car is equipped with Fast Charging as it often an extra cost option.

Finding Fast Chargers

Use PlugShare with a High Power Station filter to find DC Fast Chargers.

Tesla owners can use the Find Us part of the Tesla website to find Superchargers along their route.

DC Charging Tips

A battery that is 80% full cannot accept the full power of a DC fast charger. Similarly, to get the maximum charge rate from a Tesla 120 kW Supercharger, your battery must have less than 20% battery remaining. So on a long trip it makes sense to drive until your battery is fairly empty before recharging.

Unless you are right at your range limit to get to your next stop, it never makes sense to fully recharge your battery at a DC fast charger. To minimize trip time, charge just enough to get to your next stop plus a 10%-20% range buffer (how much buffer you need depends on your experience estimating actual range needed for your driving style, and other variables such as elevation, wind, temperature extremes, etc.).

Charging Network Membership

DC Fast Charging stations typically require membership in some sort of payment plan. Use PlugShare to find out which payment plans you need for the Fast Chargers along your route.

Tesla owners either have free unlimited for life Supercharging, or automatic membership into their pay-as-you-go plan once you use a certain number of charges per year.

Here are some links to common charging networks: ChargePoint, EvGo, Blink, Greenlots.

Copyright 2018