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Can someone please explain supercharger kilowatt rates?

Can someone please explain supercharger kilowatt rates?

I have a MS75 from November 2016. I don't supercharge that often, mostly on road trips, and just plug in, whatever, wait till it fills enough and split. Lately I've done some local charging after reading about charging KW/hr rates. Despite the chargers being rated much higher, they seem to fall to 40 KW/hr or below, even when I'm at about 50%. I was at Hawthorne today and tried the V3 charger that was supposedly 250 KW/hr and it was slower (30 KW/hr) than the conventional plug. So can someone just lay out the fundamentals of what's going on here and the basic strategies for maximizing charge rates for my vehicle? Thanks.

GHammer | 05. Januar 2020

The site is down for maintenance now but this should answer your questions.
https://teslatap.com/articles/supercharger-superguide/

The max rate for an s75 is around 90kW and so will not benefit from the 250kW V3 Superchargers.

Keys for max rate:
Warm battery
Low state of charge
dont "pair up"

NKYTA | 05. Januar 2020

Splash and dash. Charge only to what is a comfortable buffer for you. Tesla uses 20%, but you should know the weather /wind ahead of you, so 20% is sometimes overkill.

Daisy the Road ... | 06. Januar 2020

Also, pay attention to the estimate that the car gives you for battery percentage at the next SC (or destination) you will arrive at. What I have observed is that it will show some number (say 12%), then within the next 20 miles that value will inexorably creep up to an additional 10%. Using the "splash and dash" strategy, I've started taking off when it shows an arrival of 5%. Nearly every time I arrive with 15%, plenty in my opinion. Alternatively, in bad weather we'll charge to the recommended level and then skip to the next SC if possible. Both strategies save a lot of charging time.

TeslaTap.com | 06. Januar 2020

@GHammer - Thanks for letting me know.Sorry about that. I recently left it on Maintenance mode. Now fixed.

T35LAX | 06. Januar 2020

@jb

KW/hr ?
You meant kW.

rxlawdude | 06. Januar 2020

@Daisy, our experience is almost the reverse. If the expected SOC at the next destination is 15%, we usually arrive with 5-7%. I always figure 20% margin will safely get us to the destination with at least 10%.

S75RedRidingHood | 06. Januar 2020

90Kw is about the max that you could expect from S75 late 2016. I have the same model/year and I saw 84Kw max.
Just go between 20% to 80% and don't wait to get up to 90%. Superchargers are everywhere now so no need to wait for it to max out the range.

TeslaTap.com | 06. Januar 2020

@S75RedRidingHood - 90-85 kWh what I was used to in my Dec-2016 S75, but over Thanksgiving, at a full Supercharger, once the adjacent car left, I got 122 kWh for about 15 minutes. I was quite surprised! Started with SOC of 9%. This was a v2 Supercharger too. I've rarely let the SOC get that low, so I've not tried it again, but I will on my next trip. Hopefully, it's the new normal.

T35LAX | 07. Januar 2020

@ TeslaTap.com | January 6, 2020

"... I got 122 kWh for about 15 minutes..." - so, you charged at almost 500 kW charger? What is your MS battery capacity?

Bighorn | 07. Januar 2020

He meant kW. He knows better:)

TeslaTap.com | 07. Januar 2020

Should have said 122 kWh rate for 15 minutes! Good catch. Dam dropped words do make a difference :)

Bighorn | 07. Januar 2020

No, just 122 kW or 122 kWh per hour, which is wasteful.

S75RedRidingHood | 07. Januar 2020

@TeslaTap, I have seen 100kW before too but then it went down to 80kW max for my car starting about mid-2018 or so.
We do lots of road trips and supercharging. Tesla did monitor my supercharging session with me over text messaging and they confirm that because I have done so much DC charging, 21484 kWh at the time, the car will stop charging at higher rate to protect the battery. So I take their words for it. So far at 80kW max still does not slow us down and still keep us going all over the country. No complains here :)

Bighorn | 07. Januar 2020

I’m inclined to believe 122 kW for 15 minutes was a malfunction of BMS. I’ve occasionally seen aberrant numbers before and sometimes it leads to a charging interruption.

TeslaTap.com | 07. Januar 2020

@BH - Always possible, but I had no interruptions. I disconnected at about 60% SOC as it was tapering down and I didn't need any more to get to my next location. I really need to attempt to repeat it to see if it was a fluke or normal.

nukequazar | 07. Januar 2020

@TT, you still want us to believe you have a degree in EE?

Jesperj | 09. Januar 2020

With an AP2 Dec. 2016 MS 75D I've frequently seen rates in excess of 100 kW at superchargers in the past. On a recent road trip the car started out at 38 kW, and then gradually went down to 23 kW. This happened at around 8 different stalls at two different chargers at four different stops. I'm now waiting for a service appointment so they can figure out why this happened because I don't buy the explanation from the call center that "this is in order to protect your battery from damage due to frequent super charging". I had not used a super charger for six months+ when this happened.

Also, the planning for how long you need to stay is severely flawed. Many of my road trips involve skiing, which often involves a roof rack, which reduces the range by 20% or more. The estimates for how much SOC you need to leave the chargers with fails to take that into account, so if I were to believe that we'd have been stranded several times. On the most recent trip, I got an average of 443 Wh per mile, as compared to 345 with the same configuration, without the ski rack. I've asked for a formal bug report to be filed on this, but I don't have a way to verify whether it happened or not.

Yodrak. | 10. Januar 2020

"pay attention to the estimate that the car gives you for battery percentage at the next SC (or destination) you will arrive at. What I have observed is that it will show some number (say 12%), then within the next 20 miles that value will inexorably creep up to an additional 10%."
"our experience is almost the reverse. If the expected SOC at the next destination is 15%, we usually arrive with 5-7%."

My experience is that I get to the next supercharger with 10% more than was predicted when I left the last supercharger.

Bill_75D | 10. Januar 2020

My last two road trips I stopped charging when the car said I would arrive with zero percent, and I always arrived with 10-12%