20 March 2012

"Guerrilla" charging

2.5 kW transformer, "Quick 220" safety box, Think 220 volt EVSE
There are electrical outlets everywhere in the United States.  Unfortunately for EV drivers, most of these outlets supply 120 volts, unlike Europe's faster 230 volt standard.  So until there are more public 240 volt charging stations in the US, I carry extra tools on longer trips.

The "Quick 220" box in the middle is well known among EV adventurers in the US, but it does not work when your source outlets have Ground Fault Interrupters, or GFIs.  (Every outdoor outlet should have a GFI for safety.)  In the photo above there is an isolation transformer on the left which allows the Quick 220 to work from any two 120 volt outlets as long as they are on separate circuits. 

The plug on the yellow cord feeds into the transformer, the plug on the short black cord simply passes through the case and joins the neutral leg to the output of the transformer.  Without a common neutral on both circuits feeding the Quick 220, the safety relays will not engage.  This transformer is wired for 120 volts in and 120 volts out.  It must be an isolation transformer to work with the Quick 220, not an "autoformer" like many voltage converters found on the internet.

On the far right is Think's proprietary 220 volt EVSE from Europe.  There is a button on the front to select between 12 amps and 16 amps.  I bought it from a seller at www.elbil.no, which is a EV forum in Norway.  (Most of the discussion at www.elbil.no are in Norwegian, but Google Translate does an acceptable job, and I believe English posts are generally welcome.)

Common adapters, extension cords and meters
My typical long trip is once a month, 140 miles in one day.  We spend a few hours at a social event where I can park between two 120 volt outlets on separate 20 amp circuits that are about eighty feet apart.  I use a forty foot long 12 gauge extension cord (the gray one above) for the nearest outlet, and a sixty foot long 10 gauge extension cord (the black one above) running to the far outlet.  The 10 gauge cord has heavy 600 volt insulation, which makes it cumbersome but also much more durable.

There are various other adapters pictured, which are useful when there is a 240 volt dryer or kitchen range outlet available.  I have three such opportunities on various routes through nearby towns.  These outlets are found at homes, churches and businesses which are friendly to EVs.

In an older post I showed a variable auto transformer (a so called "Variac") which is useful in industrial areas where power is typically three phase, 208 volts.  The Variac allows 208 to be adjusted up to 240.  I don't use it much anymore, although it could be useful at some of the new public charging stations that supply the slower 208 volts.  I would need to acquire a J1772 receptacle to get the Variac between a public EVSE and my car.

A public EVSE at an Interstate Freeway rest stop nearby
Of course, carrying all that stuff is inconvenient, and certainly not for the average driver.  Fortunately there are more public rest stops appearing near where I live.  But I suspect I will be still be charging occasionally from conventional outlets for many years.