OpenEVSE - Open Source Charging Station

[garygid]

I would plan for the unpowered IN-EVSE to have open relays to both Power lines, both control lines (no Control Pilot and no Proximity), and even the Ground.

 

[Ingineer]

I would plan for the unpowered IN-EVSE to have open relays to both Power lines, both control lines (no Control Pilot and no Proximity), and even the Ground.

Gary, if you open the relays at the same time as you de-assert proximity, your relays are going to likely have a short life. Also, does the Open EVSE have relay contact welding detection? Most EVSE's do.

You do not need, and should not, open the power relays until the car de-asserts the pilot. Simply de-assert proximity as your "stop", then the car immediately stops drawing current. Then you can safely yank the plug, relays or not.

-Phil

 

[garygid]

Right, maybe a maximum of a 1-second delay after Stop (removing Proximity) before opening the Power relay.

 

[Norway]

Just one potentially VERY important point here:

Make sure that the vibrations in the car do not temporarily close the normally open relay contacts, such that the Leaf detects the EVSE when you are driving, and switches itself out of drive mode. (I've no idea what it will do if it happens at speed, but connecting an EVSE while the car is in Drive, will make it go out of Drive.)

 

[Ingineer]

This is true, if the car is ready and/or in drive, and not moving, the main contactor immediately drops (disconnecting the power to the inverter) and the car changes to indicating "N". (Ready --> Ig-on) I don't know what happens if this occurs at speed, I'll have to set up a special test sometime. My guess is it will not disable until you come to a stop.

The car will not charge once this happens until you hit the power button. (Ig-on --> off)

-Phil

 

[Thinwing]

i havent heard any reports from open evse users...anybody up and running yet.Also ,for some reason unable to open component list under download section..anybody have avparts list..sinc kp couch

 

[chris1howell]

The component list is under the Wiki section of the Open EVSE site. There is also athe couple of example builds in the Wiki section also with parts lists. The files in the download section are board and schematic files for the EAGLE PCB editor.

 

[Thinwing]

Ok thanks will try again...kp couch

 

[chris1howell]

It is as late in January as you can get so I owe those waiting for a board some info. Half of the boards are ready to go with new and improved code thanks to lincomatic... the other half should be ready tomorrow. PMs and E-mails will be going out soon. I will build another set in late February, I need to stock up on more PCBs and a lot of parts.

GFCI - second run
1 chris1howell - Done 1/29
2 lincomatic - Delivered 1/29
3 richard - Shipped 1/30
4 geofel - Shipped 1/30
5 geofel - Shipped 1/30
6 mitch672 - Shipped 1/30
7 commutercars - Shipped 1/30
8 mrbigh - Shipped 2/6
9 electronit - Shipped 2/6
10 ernest - Shipped 2/6
11 highdesertdriver -
12 gunther -

Next batch waiting list:
1 skywagonx3
2 caglassmith
3 ollie
4 woodust
5 Darkstar
6 fromport
7 dannyx2
8 Grahamx2
9 Tony
10 KillaWhat
11 mpt
12 garygtx

 

[Thinwing]

How about adding output to a 2 line lcd to show status?thanks for a great design!kpc

 

[chris1howell]

Something like this...? LCD has been part of the Open EVSE design from the beginning. The Open Evse board has headers on the top for 5V -GND - A5 (i2c SDL) - A4 (i2c SDA)

Add this LCD for $9.95
http://www.adafruit.com/products/181

And this i2c backpack for $10.00
http://www.adafruit.com/products/292


24 Amp - Charging by chris1howell, on Flickr

 

[Thinwing]

Thanks chris..I wondered if open evse still suported this .Led /backpack ordered...Adafruit catalog also shows a spi compliant 2 line vacumn florescent display (very similar to chgpoints commercial units)Is code to operate lcds included in firmware?.Thank again for great project..kpc

 

[chris1howell]

The code for LCD is not in the current Open EVSE firmware. However the LCD is pretty easy to add even for a non-programer like me.

Here is an Adafruit tutoral for the LCD and backpack... http://www.ladyada.net/products/i2cspilcdbackpack/
and http://www.ladyada.net/learn/lcd/charlcd.html

Following the tutorial just add the libraries to your Arduino installation and then a few simple commands is all you need such as:

LiquidCrystal lcd(0);
lcd.setCursor(0,1);
lcd.print("hello, world!");

Once you are going, send me a PM if you need help I will do what I can...

Chris

 

[GlennD]

I received my cable today from Avnet. In looking at the cable and the schematic it seems that the plug button switch is not implemented. Would it be a good idea to use that switch to control a relay that interrupts the pilot signal?

 

[Thinwing]

Small world..I also recieved plug and cable from avnet...cable is very heavy duty compared to nissan/panasonic unit...didnot see schematic for cable though..kpc

 

[chris1howell]

The proximity switch is implemented on the EV side. There is really nothing to do on the EVSE.

 

[garygid]

The proximity switch (and two suitable resistors) should be
contained within the J1772 Plug (nozzle), the switch being
activated by the "Release" button on the nozzle.

Right, this "Proximity" circuit does not connect to the EVSE,
but connects to the EV when the nozzle is plugged in.

 

[electronit]

Hi Chris,

In the example EVSE you use a 12V power supply rated 5W (450mA). Is that enough if we also want to connect the LCD ? The relay uses about 150mA, so that leaves 300mA for the cpu, and DC/DC to 5V. An LCD will use around 250mA at 5V (for the backlight), but I don't know the efficiency of the DC/DC.

As discussed by PM, I intend to add a current selection mechanism, and with the LCD, it should be "easy" to use a single push button which cycles through the different options displayed on the LCD.

Unfortunately, I've not yet found the GFCI transformer anywhere in europe, and ordering from Digikey gets really expensive due to tax & UPS "import handling fee" (my last order of 76 euro ended up costing 116 euro in total). You don't have any lying around ? ;-)

Thanks,
Mark

 

[GlennD]

Thanks for the info Chris. To the other person there is no schematic for the cable but it is a simple matter to ohm it out.

The cable was the first item to arrive. I am waiting in the board and contactor. I can not choose the enclosure until I see how big the contactor is. I want to construct for 30A even though my Leaf will use only half of that.

 

[chris1howell]

Mark,

A 5W (415ma @ 12V) supply should be fine for most basic EVSEs. The Open EVSE draws 105ma @ 12V or 1.25W and the relay should draw about 1.75w (150ma), leaving 2W or 160ma @ 12V. The 2 line LCD with i2c backpack that I have draws about 4ma @ 5V (.2w). If yours is 250ma @ 5V 1.25W, which seems a bit high, you would only have .75W buffer and may want to consider a larger power supply (or a less hungry LCD).

Chris