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Supecharger capacity utilization

rogerbohl

Member
Aug 21, 2014
63
18
USA
Learned from Tesla telephone support 12-16-2015:

Up to 5 miles of range for each charging minute may be available at a Supercharger. However, capacity is provided to pairs of charging "slots" and if one of the slots is is active use, the "companion" slot may (will?) not find that rate of charge to be available. Slot "pairs" are identifiable by number and letter (e.g., 3A is paired with 3B), but note that paired slots may or may not be physically adjacent to each other.

When arriving at a Supercharger, consequently, it is advisable to select a slot whose "companion" is not in use. If many slots are occupied, it may be necessary to share a companion pair with anther Tesla, in which case you may find that the charging rate available is substantially less than 5 miles of range per minute of charging time.

If charging is underway at two companion slots, rather than dividing the capacity equally, as one might expect, the system gives preference to the first car. Experience indicates the following to be true: If the first car of a pair of cars sharing two companion slots completes its charging, the charging rate for second car is not automatically and immediately increased: The owner of the second car must "stop charging" and "start charging" to take advantage of the additional capacity made available by the first car's having vacated its slot. (Stopping and starting charging can be carried out on the touch screen display -- controls-settings-charging -- or remotely by utilizing the mobile app.)
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,024
1,013
This (shared stalls) is the number one item that Tesla needs to teach people. In the past two days we've driven over 1,000 miles and I taught three owners this information during our stops, even though most people here on TMC already know this.

As for the second car not ramping up as first car slows down or leaves, that is incorrect and I've observed my car ramping up if I'm the second to arrive at paired stalls.
 
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Max*

Charging
Apr 8, 2015
6,670
3,719
NoVa
Experience indicates the following to be true: If the first car of a pair of cars sharing two companion slots completes its charging, the charging rate for second car is not automatically and immediately increased: The owner of the second car must "stop charging" and "start charging" to take advantage of the additional capacity made available by the first car's having vacated its slot. (Stopping and starting charging can be carried out on the touch screen display -- controls-settings-charging -- or remotely by utilizing the mobile app.)

I've read this a lot of times on the forums, but in practice I have not been able to replicate it.

When I'm #2 on the pair, and #1 leaves, if I'm watching the current, it always increase substantially.
 

jerry33

(S85-3/2/13 traded in) X LR: F2611##-3/27/20
Mar 8, 2012
19,584
22,059
Texas
I've read this a lot of times on the forums, but in practice I have not been able to replicate it.

When I'm #2 on the pair, and #1 leaves, if I'm watching the current, it always increase substantially.
That was only true with the early SC firmware. It changed to the way you described some time ago. I doubt if any SCs still behave that way.
 
Mar 11, 2010
4,518
1,358
Humboldt/Los Altos
Sad this isn't taught at delivery. I have advised that you need to start/stop charging of the first car to give priority to the later car arriving when the first car is past the fast charging part and was a bit 'flamed' by some people here. It was the only way to optimize the Superchargers without a change in the way charge is split between 2 stalls.

- - - Updated - - -

That was only true with the early SC firmware. It changed to the way you described some time ago. I doubt if any SCs still behave that way.

I hope they don't anymore. It was a bad algorithm....especially when they were leaving cars plugged in at the factory overnight!!! (..long ago)
 

green1

Active Member
Mar 25, 2014
4,548
1,121
Calgary, Alberta, Canada
I have advised that you need to start/stop charging of the first car to give priority to the later car arriving when the first car is past the fast charging part and was a bit 'flamed' by some people here.
I sure hope you don't actually advocate doing that! It's incredibly selfish of you to take over the priority spot from the person who got there first! You'll get whatever amount of charge is left over from their taper, so by the time they taper down, you'll taper up, all without being a jerk and kicking them to the other side of the priority curve.
 
Mar 11, 2010
4,518
1,358
Humboldt/Los Altos
I sure hope you don't actually advocate doing that! It's incredibly selfish of you to take over the priority spot from the person who got there first! You'll get whatever amount of charge is left over from their taper, so by the time they taper down, you'll taper up, all without being a jerk and kicking them to the other side of the priority curve.

not how it used to be,....and I would have 100% advocated it if people understood

Second car was limited to 30kW regardless of the SOC of the first car. It could be at 100% and you'd still only get 30kW
is it bad to take priority then?

If the first car was at <30kW there was no bad being done. ...especially when it was a factory TD car when the delivery center was closed!
..this was 2013 so there was only 90kW charge rates max also.
 
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ReddyLeaf

Active Member
Mar 19, 2014
1,531
2,239
WA State
If charging is underway at two companion slots, rather than dividing the capacity equally, as one might expect, the system gives preference to the first car. Experience indicates the following to be true: If the first car of a pair of cars sharing two companion slots completes its charging, the charging rate for second car is not automatically and immediately increased: The owner of the second car must "stop charging" and "start charging" to take advantage of the additional capacity made available by the first car's having vacated its slot. (Stopping and starting charging can be carried out on the touch screen display -- controls-settings-charging -- or remotely by utilizing the mobile app.)
I've also observed something similar at the 5-stall Ellensburg station this past summer. A S60 had been charging for quite a while, and I plugged into the paired stall. I was planning to have a meal and would be there an hour, so didn't really care about the rate. When I returned to check the car (maybe 15 min later), the rate was much less than 100 A (I don't remember, but maybe even as low as 30 A). I unplugged and moved to the next un-paired stall and then started charging at more than 300 A. The S60 left a few minutes later, so I know he was well tapered. Bottom line: I always plug into an unpaired stall if available, even if planning more than 20 min stop.
 

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