pbui19 wrote:... But from the limited reversed engineering schematic we manage to come up with so far, it seems that the trigger simply & abruptly switch off the relay, thus taxing the bypass (now heated from operation) resistors & caps.
Are you referring to the OBC or the EVSE schematic?
The trigger sends a signal to the microcontroller within the EVSE to stop the charging. It's not clear to me whether there is some sort of control within the EVSE such that it can open the main relay during the zero-voltage crossing of the AC mains to minimize arcing. It seems that the EVSE opens before any relays or contactors in the car.
The EVSE may have some power factor control to sense and monitor the state of the mains at every point in the waveform at 50 or 60 Hz, and so it could alsostop the charging in the event of a loss of mains power (such as from pulling the plug from the wall). It would make sense to do these things in order to reduce the risk of damage to the car.
but i don't have an EVSE schematic to know what it is really doing. There is an unknown processor chip and only one guy on the Leaf forum has figured out what it is and how to read and write the firmware.