Saturday, January 1, 2011
J1772-2009 Charging for Your EV
This is our last show. Actually our last show for 2010. We'll meet this weekend to decide what to do about 2011.
In this episode we continue the fascinating work of building battery boxes for the Speedster. While not an exciting topic, in converting almost any car to electric drive, most new builders are surprised to learn that making the car run on battery power is almost trivial. But 50% of the work centers on placing batteries and building structures to hold them.
The other 50%? Almost entirely environmental. Heat. Cooling. Lighting.
Mounting a controller and motor and getting it to run - you can nearly enough phone it in.
So to avoid making this episode a total yawnfest, we've decided to tackle a probably useful element we promised almost a year ago when we did our episode on the new J1772-2009 standard/plugs/connectors. That is, how to wire your car to actually do J1772 charging.
With the Chevy Volt and the Nissan Leaf finally shipping....er.... more or less shipping....we think you'll finally begin to see some J1772 charging stations begin to appear.
We build our cars to charge quite automatically from either 120VAC single phase or 240vac two phase power. And we almost always use a NEMA 5-15 recessed male connector on the car so that we can universally connect the car anywhere and to virtually any ordinary household extension cable - albeit you do generally want to use a heavy one.
This is mildly illegal in most respects. First, NEMA5-15 is entirely meant for 120vac operation at 15 amperes or less. In practice, we charge the Speedsters at about 25 amperes and 240vac. We simply make up a cord or "adapter" with a NEMA L6-30 or NEMA 14-50 connector on one end, and the usual NEMA 5-15 female on the other.
This is not good frankly. But it is very convenient. If you go to gramma's house, you can still plug in and get a toke on her good juice, even though there's no charge station there. We buy the best cables and connectors we can find, and while they get warm, so far no incidents.
But it isn't really kosher. And soon it will even be a disadvantage. As J1772 charge stations start to appear, at the least in the garages of friends with Nissan Leaf or Chevy Volts, and potentially public charge stations as well, we would be left out of the party.
For a "standard" I am perplexed by how "closed" all this is. The greed is palpable as the charge station vendors strive to "protect" their ground so they get prices as high as $5000 for what is little more than an AC receptacle. The "standard" does provide some safety features to keep the cord dead until it is connected (which I put in our Texaco Fire Chief charge station nearly two years ago). And the plug and connector ARE kind of quality. But it is amazing how difficult it is to find the basic connector hardware - nearly a year after adoption.
Indeed, SAE itself has been piggishly greedy - you can't find an SAE J1772-2009 PDF online anywhere. They are "selling it" on their web site with digital rights management and dire warnings about copyright infringement. Copyright infringement on a public standards body? This is just inexcusable.
In any event, there IS a conspiracy to control these charging stations and maintain high profit margins on the charge stations. The connectors are a couple of hundred dollars each depending on how long and what kind of cable. None of it warrants $5000 or even $2500, I don't care how many approvals it carries. And the whole concept of having a licensed electrician and permit to install it is laughable. Some of them actually just plug into an existing NEMA receptacle just as we do with our cords. In any event, adding a 60amp or 100 amp circuit breaker to your panel, and running a piece of AWG10 orange 3-wire plus ground to a convenient place in your garage, is work ANYONE can do AND SAFELY.
There are numerous home wiring books at the local hardware store, the wire, the NEMA receptacles, and the circuit breakers. And in almost all localities you are entirely legal to do such wiring ON YOUR OWN RESIDENCE without license or permit.
But back to the car. If you buy a J1772-2009 inlet connector and mount it on your car, and connect the two phase pins and the ground pin to your charger, you won't ever be able to charge your car at any of these charging stations.
This is because the car has to provide some "signals" to the Electric Vehicle Support Equipment (EVSE) aka Charge Station to turn it on. These mysterious "signals" are actually trivial They are actually a single diode, two resistors, and a switch. Here's the diagram:
Click on the diagram to blow it up.
For those who find wiring two resistors, a diode, and a switch, a challenge, you can buy ready made adapters from Rush Dougherty at http://www.TucsonEV.com. He has the connectors you'll need anyway, including a nice plug with a full 8 meter (25 foot) long cord. And he has made a little adapter box with switch and light as well.
With our wiring, or Rush's box, you simply connect the J1772 plug to your car, and then turn on the switch. This drops the sense voltage to 6 volts in the EVSE and triggers the unit to turn on the 240vac power.
When you're done charging, you hit the switch to shut OFF the power, THEN remove the cord. Very much a safety improvement over our current methods.
And it will allow you to configure YOUR electric vehicle to use the new charge stations wherever you find them.
In a future video, we'll go into some detail about how you can set up a J1772 charging station of your own, for HUNDREDS of dollars instead of thousands. We're just going to add a cord to our Texaco pump, and switch on the power manually after you connect the cord as we do now.
But another viewer, David Kerzel of Modular EV Power LLC is working on a printed circuit board control circuit for a home charge station with all the bells and whistles of J1772-2009. We'll follow his progress and hopefully have something to show in a future episode for you to build your own charge station at much less cost. His design will use all UL listed components in the contactor and connectors and so forth, and he intends to include instructions on how to get it permitted and inspected and approved if that be your hearts desire.
See you next year.