For my Model 3, the EVSE unit is attached about every other day. I set the start time for after midnight and usually rate of charge for 22A. My 240v, 14-50 outlet will easily support 40A. When choosing 22A, dose the car "communicate" with my EVSE or is this thru the duty cycle PWM? I ask, because I'm trying to understand how another after market EVSE would work. I also monitor the status using my phone App; Is this again a communication with my car or my EVSE?
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Charging Rate Control for Tesla vs after market EVSE.
- Thread starter SimbadCA
- Start date
Tam
Well-Known Member
I guess there is some communication with Tesla and non-Tesla charger as I tried to crank my Amperes above 30A and I could not while I could with a Tesla charger.
Thanks. I have found the following:
"Communication between the EV charger (EVSE) and the EV is performed using PWM signalization over Control Pilot as per IEC 61851-1 and J1772."
The PWM is a +/-12V square wave that changes width (duty cycle) depending on the amperage. The part still has me confused... I would think that the EV is controlling the amperage with its on-board unit (OBCM); perhaps the EVSE sends the PWM signal to communicate to the EV what its amperage limitation.
"Communication between the EV charger (EVSE) and the EV is performed using PWM signalization over Control Pilot as per IEC 61851-1 and J1772."
The PWM is a +/-12V square wave that changes width (duty cycle) depending on the amperage. The part still has me confused... I would think that the EV is controlling the amperage with its on-board unit (OBCM); perhaps the EVSE sends the PWM signal to communicate to the EV what its amperage limitation.
israndy
Supercharger Hunter
You got it, that is the limit the EVSE can provide, so the car is told not to draw more, if it tries the EVSE disconnects, that's why it's there and not just a wall plug with a breaker, more automatic, just plug any of them in and they communicate with your car and it charges.
This is ALSO how some EVSE can be set to control your cars charging rate based on software features, either a Tesla Wall Connector or a 3P EVSE can change the rate they want to charge at so features have been added to some that will track the amount of solar you are generating and change the charge rate based on that.
But when you are controlling your car with the app and are changing the rate you are telling the car over WiFi what rate to use (as long as it's below the previously agreed upon rate with the EVSE). Ultimately it's the car that does the changing of the charging rate, but if it goes too high the EVSE always has a veto.
This is ALSO how some EVSE can be set to control your cars charging rate based on software features, either a Tesla Wall Connector or a 3P EVSE can change the rate they want to charge at so features have been added to some that will track the amount of solar you are generating and change the charge rate based on that.
But when you are controlling your car with the app and are changing the rate you are telling the car over WiFi what rate to use (as long as it's below the previously agreed upon rate with the EVSE). Ultimately it's the car that does the changing of the charging rate, but if it goes too high the EVSE always has a veto.
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