Wednesday, July 1, 2009

Underwriters Laboratories approves charging plug

It was announced on Sunday that a standard for EV charging will be voted on in July. The standard is known by the catchy name of "SAE J1772". This is why we hire right brained people to come up with the names of things. Yet, I count on the left brained engineers to be in charge of designing the tools we will use for transferring electrons racing through the grid into the battery of my car. So, don't worry about remembering the technical name (J1772) because the important piece is how fast you can charge, which is based on three levels.

Level 1 is already in effect. This is essentially any 120 Volt 20 amp plug. You have them all over your house and probably your garage. Charging at this level will be fine for most people who want a good 4-5 miles of range per hour of charging. Starting a charge at midnight, for instance, will give you 28-35 miles of range by 7 am. If your car is a PHEV, that may be enough for your daily commute.

Since many drivers of EVs will want to charge faster than the 120V plugs will allow, a 240V plug will be necessary. Level 2 charging will be 240V at 12 amps up to 80 amps. Telsa's High Power Connector, for instance, charges at 240V/70A, fast enough to pump 53 kWh into the battery in about 3.5 hours.

The standard discussed from the AutoBlogGreen article will allow charging up to the 240V/80A limit, but will also allow your car to communicate with the utility supplying the electricity and the company supplying the charger. The utility will be able to control the charging to take advantage of the intermittent wind at night, or to prevent too many cars from charging during peak daytime hours when the grid may be over loaded. With "vehicle to grid" technology, utility operators will even be able to "buy" kWh from EV owners during peak hours to stave off a rolling black out.

This standard hopefully will be welcomed by all the car makers that are planning plug-in vehicles since they will all want to build the proper connector into their vehicles from the start. Let’s work to make this a reality.

Source: Autoblog Green
Image: T3 Motion C-3

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