JoeS wrote:If you are trying to generate the 220vac from inside the car, that is a whole different issue, and actually the topic of this thread, and a much more complicated problem.
Speaking on Herbie's behalf (because I think he's also after what I'm after), I think he's after something a little different to what this thread is about. Herbie also posted the same question on this http://myimiev.com/forum/viewtopic.php?f=14&t=4444
and (assuming he's after what I'm after) we're wanting to install a 220vac socket/feed in a triplet, piggy backing off of the 220vac coming from the J1772 socket, so when the car has finished charging, the control pilot gets hijacked (for want of a better term) to turn the EVSE back on. Tiborx8 was working on something which overlapped with this. Then the 220vac 'socket' can be made live, so that it can be used to preheat the car, probably controlled by a timer or through a 4G/Wifi controlled switch. The preheat being provided by a dedicated 220vac fan heater put in a useful position in the car (but not likely to burn it to the ground).
What I'm not sure about is how to determine with absolute certainty that the car has stopped charging before putting the 220vac fan heater on (so not to overload the cables running to the J1772 connector both in the car and to and from the EVSE). My guess would be to use a relay which would disconnect the 220 vac Fan Heater socket when the car is charging, although I don't know where to get the feed from for this. Or possibly have a double pole double throw relay on the 220vac live and neutral between the J1772 and the car charger so it's impossible for the car charger and the 220vac fan heater to have power at the same time. Actually, I quite like that idea; But I don't know what would happen if the car was requesting a charge from the EVSE and was charging at 16amps, then the relay switches the J1772's 220vac over to fan heater's circuit and the Control Pilot hijack kicks in to keep the EVSE switched on. Would the car identify a fault if the charge was to stop whilst requesting through the Control Pilot, but the proximity detection pin was still connected to the EVSE? I suppose the extreme way around this would be a 4 pole double throw relay which switches the J1772's 220vac live, neutral and the CP and PD all off of the car charge circuit and onto the 220vac fan heater circuit and from there we spoof the CP and PD to control the EVSE. I know very little about how the CP works other than knowing that depending on the voltage, it has three states: No Connected, Connected not charging and Charging. I don't understand if the EVSE's charge current command will have an impact on our implementation as we'd keep the current below 10amp to save any overloading.
The above is a big ol' rambling brain dump, hoping that someone much smarter than I will look at it and know exactly hot to do this or parts of this.