How to charge your electric car in public

Once you have a home charger for your electric car, you'll also probably want a way to charge it up in public while you're out and about. The United States now has almost 20,000 public charging stations. But while most plugs fit any electric car, it's not as easy as just pulling up and using one.

Most public charging stations are connected to one of a handful of networks. And to activate them, you have to essentially be a card-carrying member, identified through RFID or bar-code scanning technology.

Of course, a few chargers are free, and an increasing number can be activated directly by credit card. Charging networks are also beginning to post 800 numbers on their chargers, so that EV drivers who aren't members can call and get signed up or pay for a charge. But the effort to build charge stations that don't require memberships or use a universal membership is growing in fits and starts, according to EV drivers and networks operators we talked to at last month's Electric Drive Transportation Association meeting in Indianapolis.

Most of the charging networks have merged their payment systems into a single EZ Charge card. But Chargepoint doesn't participate. The EZ-Charge card will activate ChargePoint chargers – but pricing is not guaranteed, and the charger isn't even guaranteed to be accessible. 
Tesla doesn't participate either, but its Superchargers are free to Tesla drivers. So, yes, it is a bit complicated.

Think of the network membership like a cell-phone rate plan: You pay by the month or by usage, make your best estimate of how much public charging you'll need to do, and pick from a wide assortment of bewildering options before signing up. (Use our interactive Guide to alternative fuels and EV charging stations.) Some networks now offer home installations, as well.

In the meantime, if you're considering an electric car and wondering what you need to do to get charged up, look for what networks are most prevalent in your area and join that network. We like the idea of the EZ Charge card that can activate several networks, but at this point, it won't activate the majority of charging stations. If you live in California, as most electric-car drivers do, the network of credit-card operated charging stations from eVgo is expanding. But it still may be worth joining Chargepoint, because it has the most chargers so far. While navigation systems, available in all electric cars, can direct you to the nearest public charger, they can't always tell you what you need to get charged up once you get there.

Here's a list of the biggest players and how they charge.

*All have Level 2 (240-volt) and Level 3 (direct current) charging except Tesla, which offers Level 3 only.
**App lets users see what stations are in use
***Offers bundles with home charging stations
**** L3 SAE Combo plugs coming

—Eric Evarts