High Power Wall Connecter, can you throttle it?

[SCW-Greg]

Can you throttle the output of the High Power Wall Connecter?

Assuming you have 100A coming in to the HPWC, I've heard conflicting stories from the Tesla reps that charging the Model S at 80A slightly shortens the battery life each time. However, it would be handy to have that high amp capacity for the occasional/urgent need to get back out on the road sooner, but would prefer to have the ability to throttle down the HPWC to 30 or 40A for normal day-to-day charging.

Thoughts?

[ChadS]

Yes. Perhaps not at the HPC, but in the car. With the Roadster (I assume the S will be similar), you can tell the car to pull anywhere from 12A to 70A. Once you set a number in your garage, the car remembers that number for that location until you change it again.

Most Roadster owners have their cars set to pull 32A, even if they have a 70A HPC. I usually have mine at 24A--more grid-friendly, and still plenty fast to have it full by morning. (I don't have an HPC; I have a third-party RFMC that can pull max 40A from my 14-50 outlet).

[Jason S]

Via the car you can set how much power you attempt to draw.

Just set it to 30 or 40A

[SCW-Greg]

Yes. I usually have mine at 24A--more grid-friendly, and still plenty fast to have it full by morning.

Great feedback .
Thanks (Jason too)!

[7racer]

Wait!! Did I miss the memo? Lol should I be chargin my roadster thru the UMC at 30 or 40????

Yes. Perhaps not at the HPC, but in the car. With the Roadster (I assume the S will be similar), you can tell the car to pull anywhere from 12A to 70A. Once you set a number in your garage, the car remembers that number for that location until you change it again.

Most Roadster owners have their cars set to pull 32A, even if they have a 70A HPC. I usually have mine at 24A--more grid-friendly, and still plenty fast to have it full by morning. (I don't have an HPC; I have a third-party RFMC that can pull max 40A from my 14-50 outlet).

[strider]

Wait!! Did I miss the memo? Lol should I be chargin my roadster thru the UMC at 30 or 40????

Through some investigation by Tomsax, he determined that 40A was the optimum balance between charging overhead and charging the batteries. Higher or lower than that and a greater percentage of wall power is going to cooling and managing the batteries. It's a tiny difference (until you get down to 120V) but if you don't need the speed of 70A why not save a few pennies/night?

[ChadS]

Tomsax's blog is HERE.

40A is indeed most efficient, by a small amount. I charge at slower speed (24A) on the theory that the lower power level is better for the grid than the small amount of extra energy. And similarly that the lower power level may be slightly better for the batteries. But even if I'm guessing right, the differences are probably small.

[SCW-Greg]

Tomsax's blog is HERE.

40A is indeed most efficient, by a small amount. I charge at slower speed (24A) on the theory that the lower power level is better for the grid than the small amount of extra energy. And similarly that the lower power level may be slightly better for the batteries. But even if I'm guessing right, the differences are probably small.

Excellent resource (Hat's off to Tomsax). Thx!

[7racer]

thank you!!

[SCW-Greg]

Anyone have dimensions on the HPWC?