[North American] - Macan does NOT support 11 kW charging??? Home / Residential charging update (using Tesla Universal Wall Charger)

[dgkhn]

small nit…

what your'e seeing is 9.1/9.2/9.3 kilowatts (kW) not amps

Yes. Typing too quick. Corrected now.

 

[daveo4EV]

Yes. Typing too quick. Corrected now.

it's all good we're here to support each other ;-)

 

[whitex]

How is the EVSE signaling 44 amps to the car if that is not a J1772 signal? If it can't signal 44 amps, how does it supply 44 amps?

I looked a little deeper, it might be possible, or it might just drop to the next lowest, so might signal 40A. Below is a slide from this slide deck (which by the way is a good overview of the J1772 signaling). It shows discrete steps for the duty cycle.

What is unclear however, is whether the pilot signal can have more steps in between, or is it completely analog/continuous (so even steps of 0.001% or smaller). I have come across mentions that 50% means 32A max, though from the above this duty cycle would have to be 53.33% for 32A.

So it might be possible to signal 44A, even though it's not a typical value since that would imply 55A breaker which is not typical.

@daveo4EV , I given the above, I wonder if your PMCC duty cycle modulation or Macan duty cycle measurement are just not very accurate, and the Macan just reads PMCC's 40A as 40.7A (67.83% duty cycle instead of 66.67%).

 

[daveo4EV]

I looked a little deeper, it might be possible, or it might just drop to the next lowest, so might signal 40A. Below is a slide from this slide deck (which by the way is a good overview of the J1772 signaling). It shows discrete steps for the duty cycle.

What is unclear however, is whether the pilot signal can have more steps in between, or is it completely analog/continuous (so even steps of 0.001% or smaller). I have come across mentions that 50% means 32A max, though from the above this duty cycle would have to be 53.33% for 32A.

So it might be possible to signal 44A, even though it's not a typical value since that would imply 55A breaker which is not typical.

@daveo4EV , I given the above, I wonder if your PMCC duty cycle modulation or Macan duty cycle measurement are just not very accurate, and the Macan just reads PMCC's 40A as 40.7A (67.83% duty cycle instead of 66.67%).

could be lots of things…let's get the source code and figure it out!!

 

[whitex]

could be lots of things…let's get the source code and figure it out!!

It would be easier to hook it up to OpenEVSE and sweep the pilot duty cycle while measuring current and voltage and noting the car's power display. How much time you got, or how determined are you?

 

[daveo4EV]

I'm hoping to make it Porsche's problem - I'm going to visit service shop on Monday so they can document/record it doesn't charge above 9.6 kW on their 19.2 kW Porsche Wall Charger - once we have that they can escalate for Porsche to be confused and ignore it.

 

[dgkhn]

I looked a little deeper, it might be possible, or it might just drop to the next lowest, so might signal 40A. Below is a slide from this slide deck (which by the way is a good overview of the J1772 signaling). It shows discrete steps for the duty cycle.

What is unclear however, is whether the pilot signal can have more steps in between, or is it completely analog/continuous (so even steps of 0.001% or smaller). I have come across mentions that 50% means 32A max, though from the above this duty cycle would have to be 53.33% for 32A.

So it might be possible to signal 44A, even though it's not a typical value since that would imply 55A breaker which is not typical.

@daveo4EV , I given the above, I wonder if your PMCC duty cycle modulation or Macan duty cycle measurement are just not very accurate, and the Macan just reads PMCC's 40A as 40.7A (67.83% duty cycle instead of 66.67%).

Thank you for diving into this; now I'm really curious. I was thinking that if the signaling is discrete steps, then setting to 44A could cause it to signal 40A. Or it might cause some charging sessions to abend. So, to be on the safer side (not that worried about the 55 vs 60 amps ampacity thing), I've returned both my HomeFlex's to 48 amps (although one of them put up a bit of a fight when I tried to do that at first).

However, given that the above says Duty Cycle = Amps / 0.6, my suspicion is that 44 amps causes the EVSE to signal 73.33%. Also, another hint is I believe 16 amps is a standard J1772 charging level, and it's not on the chart (would be 26.66 %), so I'm kind of guessing continuous signaling should be supported.

 

[Dragon Tourniquet]

A few years ago (2 cars and 1 house ago) I had a JuiceBox Pro that I used the API to dynamically set the max charge rate based on the amount of solar our system produced. The minimum was 6 amps, but above that level it could be set to any integer up to the max charging rate, and I would see the difference in draw within 15s.

 

[dgkhn]

So I've been doing a little Googling. I realize this is not close to definitive, but if you look at the explanation here, it certainly looks like the duty cycle function is continuous, not a stepwise function.

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