J1772 plug/cable from China with proximity problem

[pgrovetom]

I ordered a J1772 connector from China for around $100 and got a big surprise during prototyping my EVSE circuit. I thought about using a micro-controller but realized its not really needed as I didn't have a development environment. But when I looked into the J1772 Proximity function, I realized the S3 switch and 150/330 Ohm resistors must be built into the plug. The one I received had the proximity pin wired to the cable (like the pilot conductor/pin) and the latch had no S3 switch or the 150/330 resistors. I made the dumb mistake of assuming even a Chinese J1772 plug manufacturer would have properly dealt with the proximity function - my bad assumption. Before you buy one anywhere, make sure they have implemented the proximity function in a manner that will work correctly as returning it can be difficult. I suspect they may have sent me a prototype without the proximity implementation.

The latch which releases the plug from the receptacle must be tied the J1772 defined S3 switch which causes the EV to see the 150+330=480 Ohms when the latch is pressed so it can cut its current draw to prevent arching upon removal. While engaged, S3 is closed presenting 150 Ohms to the EV so the EV knows its safe to draw current. I'm going to need to either buy another J1772 plug/cable or implement the proximity with a disconnect switch on the EVSE. Its still much cheaper than buying one. That of course requires the operator to know to engage an EVSE switch before pulling the plug out - not fool-proof.

 

[davewill]

Any way you could mount a micro switch inside the handle so that the latch button could still trigger the proximity function?

 

[DarkStar]

The cable that came with my EV-Charge America EVSE had the exact same issue. Looking inside of it though, I'm pretty sure I'll be able to throw a microswitch and the proper resistors (be sure to use 1%) in it.

I've since found out that even though Tuscon EV has the same looking cables, they are wired properly with microswitches and resistors.

 

[pgrovetom]

I'm considering trying to install a micro-switch inside but it looks difficult to make it reliable. If that doesn't work I'll but a push-button on the EVSE box for disconnect. Since I'm the only one who uses it and typically the charging is done by time I remove it, its better than buying yet another J1772 cable/plug. Does anyone know if the Leaf needs to see the proximity 480 Ohm followed by 150 Ohm on insertion - latch push and release - in order to begin its charging sequence? It doesn't seem to be functionally required on insertion but the software might want to see the full sequence. If I did need a removal switch on the EVSE that simulates the latch push and release, then it would be nice if it wasn't required on insertion and removal. This is one of those little subtleties that could vary from EV to EV. The J1772 spec seems to only indicate that the proximity switch S3 is only relevant during removal but the software could look for it during insertion also.

 

[davewill]

I'm considering trying to install a micro-switch inside but it looks difficult to make it reliable. If that doesn't work I'll but a push-button on the EVSE box for disconnect. ...

At least put the push button on the J1772 plug. Much more convenient that way, plus your EVSE design doesn't have to change if a proper plug with the proximity feature is substituted.

 

[highcountryrider]

I tried this this morning. My AV EVSE and/or the LEAF do nothing when I push the
release button. Charging and/or climate control continue to operate until I actually
pull the J1772 out of the socket. :?

 

[davewill]

I tried this this morning. My AV EVSE and/or the LEAF do nothing when I push the
release button. Charging and/or climate control continue to operate until I actually
pull the J1772 out of the socket. :?

We've had this discussion elsewhere. There are no visible signs, but when you measure the current draw, it does drop to zero when you push the button.

 

[highcountryrider]

Oh.