HPWC Charging Limited to 79A

[Andyw2100]

Again weird. The Tesla rep who stopped by my office with a brand new P90D was getting 80/80 amps at my station, but my early 2013 S85 only sees 79/79.

Well, that --IS-- consistent with the issue being resolved for newer cars, but not for yours.

 

[breser]

Just to clarify. The issue here that I had was that the car was only allowing up to 79A to be selected in the adjuster. I still see 79A a lot in the actual charging amperage. But the car hasn't shown 79A as the maximum possible charging selection since the firmware update that fixed the issue. My guess would be slightly different hardware that had different error ranges than the software was aware of and caused it to calculate the duty cycle signal incorrectly coming up with 79A.

 

[Andyw2100]

Just to clarify. The issue here that I had was that the car was only allowing up to 79A to be selected in the adjuster. I still see 79A a lot in the actual charging amperage. But the car hasn't shown 79A as the maximum possible charging selection since the firmware update that fixed the issue. My guess would be slightly different hardware that had different error ranges than the software was aware of and caused it to calculate the duty cycle signal incorrectly coming up with 79A.

And if I may, I'd like to clarify your clarification, at least as I recall things at the time. (We were experiencing the same issue.) Obviously feel free to correct me if any of this is wrong as it applied to you.

When you write you could only select up to 79A in the adjuster, this would be true for a location once you had plugged in there, and the pilot signal was read or saved. But if that was cleared, or for any new location, or the first time you tried to charge, you would be able to select 80 on the selector, but it would immediately change to 79 Max either once you plugged in or once you started charging (I don't recall which, but I think it was as soon as you plugged in.) From that point on, the display would show 79/79 instead of what it sometimes shows now, which is 79/80. And from that point on you could no longer select 80.

Right?

 

[breser]

And if I may, I'd like to clarify your clarification, at least as I recall things at the time. (We were experiencing the same issue.) Obviously feel free to correct me if any of this is wrong as it applied to you.

When you write you could only select up to 79A in the adjuster, this would be true for a location once you had plugged in there, and the pilot signal was read or saved. But if that was cleared, or for any new location, or the first time you tried to charge, you would be able to select 80 on the selector, but it would immediately change to 79 Max either once you plugged in or once you started charging (I don't recall which, but I think it was as soon as you plugged in.) From that point on, the display would show 79/79 instead of what it sometimes shows now, which is 79/80. And from that point on you could no longer select 80.

Right?

I think so based on your explanation. When I plugged in I would either get a max of 79 or 80A. Mostly just 79A but every once in a while it would go up to 80A. After charging for a while even when it was at 80A it would change to 79A and would not go back to 80A unless you unplugged the car and plugged it back in. Once it went down to 79A the car would stay at 79A at the location unless you raised it back to 80A (if you happened to get lucky and it read that maximum). But it would always end up back at 79A max.

 

[FlasherZ]

And if I may, I'd like to clarify your clarification, at least as I recall things at the time. (We were experiencing the same issue.) Obviously feel free to correct me if any of this is wrong as it applied to you.

When you write you could only select up to 79A in the adjuster, this would be true for a location once you had plugged in there, and the pilot signal was read or saved. But if that was cleared, or for any new location, or the first time you tried to charge, you would be able to select 80 on the selector, but it would immediately change to 79 Max either once you plugged in or once you started charging (I don't recall which, but I think it was as soon as you plugged in.) From that point on, the display would show 79/79 instead of what it sometimes shows now, which is 79/80. And from that point on you could no longer select 80.

Right?

As an observation, this is what the Model X does when the voltage is higher than 240V... you see the maximum is at 72A *before* you plug in, but the minute you plug in, the car will show somewhere between 68-71 based on the voltage the car senses. Tesla explained that the phenomenon occurred because of the higher voltage present (my home operates between 248-253V usually) and limits the charger to 17.5 kW.

 

[breser]

As an observation, this is what the Model X does when the voltage is higher than 240V... you see the maximum is at 72A *before* you plug in, but the minute you plug in, the car will show somewhere between 68-71 based on the voltage the car senses. Tesla explained that the phenomenon occurred because of the higher voltage present (my home operates between 248-253V usually) and limits the charger to 17.5 kW.

Interesting. Though I don't have voltage over 240V very often at my house, so I don't think that was the issue in my case.

 

[FlasherZ]

Interesting. Though I don't have voltage over 240V very often at my house, so I don't think that was the issue in my case.

It's definitely not the case for all Model S's, as my Signature car has shown an 80A pilot & maximum charging current even at those high voltages. I'm wondering if one of the generations of chargers was limited at one point.