EV Charging Stations aka EVSE

EV Charging Stations aka EVSE

Posted 4-1-2014 in Reviews by Christopher

An electric car charging station is usually the first accessory that a new EV driver purchases for their car. A charge cord comes with every electric car sold but in the US almost all of them are 120 volt trickle chargers.

A 120v charge cord only provides about 4 miles of range per hour. If you don't drive very much, that might be enough to get by. If you charge for 12 hours, that's 48 miles. 

Most people opt for a 240v charger rated between 16-30 amps. Those units provide between 10 to 20 miles of range per hour of charge. That allows you to come home from work, charge for an hour or two, and be ready to go back out for a drive that evening. It also helps ensure that you can charge within the cheapest rate window offered by your utility.

The choice of 16 or 30 amp unit depends on what kind of EV you drive and your budget. A Chevy Volt or Spark, for example charges at a maximum of 3 kW, which what a 16 amp unit puts out at 240v. So those cars charge at the rate of 10 miles per hour.

A Fiat 500e or Ford Focus Electric charges at a maximum of 6 kW, so those cars can make full use of a 30 amp charger and charge at the rate of 20 miles per hour.

The formula is Volts x Amps = Watts for the mathematically inclined. If you're wondering why the numbers don't line up perfectly it's because electrical circuits are designed to run at 80% of the maximum rating. So the actual charging rate is a little less than the rated value but it's close enough for our rule of thumb examples.

The lone exception to the 120v charge cord default offering is Tesla, who provides as standard equipment a beautiful, elegant and powerful 240v 40amp charger that also happens to be portable, and will also plug into a 120v outlet if necessary.

I'm not sure why all manufacturers don't make that kind of flexible and capable charge cord available but it probably has as much to do with risk aversion as it does cost. Tesla has had to update their software and swap out the plug adapter on their charger because some of the units ran too hot.

Fortunately a couple of vendors provide excellent aftermarket chargers that provide a combination of higher charge rates, portability and flexibility. We'll review some of those options in this section.

In the interest of being totally complete, Tesla also offers a dual charger option that charges at over 50 miles per hour, but we'll leave that review for Tesla specific web sites.

Tesla and other electric car manufacturers also provide special commercial fast charging sites that can charge EVs in about 30 minutes, but this section is focused on gear you can buy for your car and use at home or work. If you're interested in learning more about these commercial Quick Chargers, Electric Car Insider magazine has some good write-ups. 

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