Sorry, I should be more specific with my question. The J1772 spec shows a partial schematic but doesn't discuss how the the switch inside the J1772 connector and 330/150 ohm resistors and actual detection circuit uses them.
Its the purpose both functionally and for safety or reliability of the engage lock button and the disconnected, being engaged but S3 open and fully engaged with S3 open - 3 states are actually used by EV that I'm wondering about. Since its vague, I can't help but wonder if the Leaf, Volt and other EVs behave differently as the not inserted to being inserted lock button pushed to fully inserted plus if the human doing it starts, stops, pushes button, changes mind and or is erratic... etc.. what happens? Does it matter?
The J1772 spec shows a diagram with a switch, 150 ohm and 330ohm resistor that appears to be integrated into the J1772 connector. I says that when the connector engagement lock is pushed, the 330ohm resistor is shunted such that the 150 ohm resistor appears from ground to the proximity pin. Once engaged and the lock released, the 150 + 330 ohm resistors or 480 ohms appears to ground. The EV provides a 330 ohm pullup and a 2.7K pulldown to ground. When the connector is disconnected, the 330 ohm pullup dominates and the EV proximity detection circuitry sees 90% of the +5V which tells the EV, the connector is not inserted. When the connector is inserted with the lock pushed shunting the 330 ohm, 150 ohms appears to ground and the EV proximity circuitry sees about 1/3 of the +5v due to the series 330 ohm to +5v and 150 ohm to ground. Then when the lock is released and the connector fully engaged, the 480 ohm ( 330 + 150) results in 480/(480+330) * 5V to the proximity detector.
So it looks like they want to discriminate between connector not engaged, connector being engaged with lock pushed and fully engaged and lock released. My real question is does the Leaf actually look for the full transition and how it reacts.
Resistance across proximity pin to ground equal to:
open = not engaged
480 ohms = being engaged with lock being pushed by installer
150 ohms = fully engaged = ready and safe to connect power and charge
The J1772 connector and cable I have appears to have no integrated resistors or electrical switch S3 tied to the lock button.
Is it really necessary to provide the lock button interlock?
If the EVSE simply had the 150 ohms to ground without the additional delay due to the lock button interlock state (480 ohms), will it result in any functional issues. It seems one purpose of this scheme is to possibly assist in prevented arching of the AC pins.
On initial insertion, the AC is disconnected due to the pilot/state sequence. But on removal, the charging could be underway and arching could occur if the connector is pulled out. If the EV detects the lock button being pressed and shuts off its current draw, then this scheme could help prevent any removal bounce arching.
Does anyone know specifically how this scheme is used on the Leaf and what would be the downside to not providing the button pushed 480 ohm removal condition? Is the risk functional or arching protection or both?
Since my connector does not implement the scheme, I could have a switch on the EVSE to simulate the lock button switch. Its not as good because one needs to remember to use it but my only other option is getting a new connector/cable.
Does anyone have any additional thoughts on the implications of the scheme and how the Leaf uses it?
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