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Supercharging speed stuck at 66kW.

axalam

Member
Jul 6, 2020
41
3
NYC
Hey everyone, I just bought a used 2017 90D Tesla and I am very confused as to why my car is stuck at 66kW at superchargers. This is at day and night with no traffic at the superchargers. I verified that the superchargers I went to support 150kW. I am very confused as to why my car won't go beyond 66kW. I even went to the superchargers when there is no one around but still no luck. My car has the high amperage charger upgrade but I believe that only affects home charging and not supercharging. So can someone explain to me why is this happening and what I need to do to get it fixed?

I had the Tesla mobile service come out to fix another issue and when I asked them about this particular issue, they said that my car had a single charger onboard and there was no "slave". Apparently to support upto 150kw there is a "slave" and a "master" and that I would have to upgrade to a dual charger. I believe this information was wrong and he was talking about the 48A charger upgrade to dual. I already have the 72A charger upgrade and I think he was incorrect. Can someone clarify if he was right or wrong?

I am very lost on what to do here.
 
Subscribed. I charge at 2 superchargers that are in my area. One has 5 stalls and 150Kw and one has 250Kw and 8 stalls. I have been at both of these when no one is using them. Our 2020 MSP (with 80-100 mile left on battery) gets about 65Kw at 1st and slowly goes down from there. I also make sure to pre-heat the battery before arriving. Unfortunately I don't know the answer to your question, but I would like to better understand Tesla supercharging. We have lifetime free supercharging if that matters. MSP has 3000 miles on it.

M
 

ucmndd

Well-Known Member
Mar 10, 2016
7,703
14,990
California
I had the Tesla mobile service come out to fix another issue and when I asked them about this particular issue, they said that my car had a single charger onboard and there was no "slave". Apparently to support upto 150kw there is a "slave" and a "master" and that I would have to upgrade to a dual charger. I believe this information was wrong and he was talking about the 48A charger upgrade to dual. I already have the 72A charger upgrade and I think he was incorrect. Can someone clarify if he was right or wrong?
This is a full heaping of grade A bullshit, you are correct.

How are you concluding your car is “stuck” at 66kw?

How many different times have you observed this?

How warm was your car/battery?

What was your state of charge when plugging into the supercharger?

Have you tried different supercharger stations?

There are lots of variables, some in your control and some out. But basically, the car will charge as fast as it can given conditions. Tesla also has been slowing down supercharging speeds on older cars, high mileage cars, and cars with a high amount of lifetime DC charging. You might be running into that as well.
 
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Ostrichsak

Active Member
Sep 6, 2018
3,808
4,430
Colorado, USA
What is your SoC (State of Charge) during these Supercharging sessions?

The representative you spoke with was 100% wrong. Supercharging is DC to DC so no conversion happens. It just shoves power directly in & bypasses the onboard charger(s). The onboard chargers ONLY come into place when you're charging off of AC power as it needs to convert it to DC to store in the batteries. There have been different versions over the years (single, dual, newer style standard & newer style w/high speed unlocked, newer style physically limited to standard, etc) across the different vehicles but for most who only have the ability to charge at 240v @ 32A these differences are irrelevant.

tl;dr You should be seeing higher Supercharger rates so long as your SoC is in the 0-50% range. It tapers down to protect the battery cells the higher your SoC.
 
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Rocky_H

Well-Known Member
Feb 19, 2015
7,314
9,011
Boise, ID
This is a huge thumbs up of support for @ucmndd and @Ostrichsak .
The onboard chargers have nothing to do with it. But my biggest question would be about your state of charge and battery pack temperature. There's not a place to see the temperature directly, but it's more of: "Did you just wake up and drive a cold car 10 minutes to the station? It won't be hot enough yet."

I know there is some of that capping of Supercharging rates on older cars, but I've usually only heard of that down to about 90, or maybe 80 kW on the top. 66 kW is a bit too low for that to be the charge speed throttling.
 
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S

Saabstory88

Guest
I have the same issue on my 100D, but it is only happening on V2 chargers, V3's work fine. I posted a thread in the Supercharger forum with more details. Also, due to a recent service request about this issue, I have had my car confirmed as in good health. I use the same 15 or so stalls every two months or so, and have a pretty good sampling. This used to be a once every 10 sessions thing, now it's an every session thing. I've been looking for more people who've had the experience to try and determine whether this problem is with the car, or with the supercharger network.

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