# First time Supercharging.... help me understand these numbers



## Power Surge (Jan 6, 2022)

So I've been wanting to try out the local Supercharger near my house, and today I gave it a try. The car was at 52% when I arrived, and i charged it to 90%. I did select the station on my map, and it did show preparing battery for fast charging as I was headed there.

This is an 8 stall station, with the spec showing max 250 kwh (not sure if that unit is correct). I know the stalls are shared 1a/1b, 2a/2b, etc. There were 4 cars there already, so I had to share a paired stall with a Model S.

The first portion of charging, my car was showing 68 kW 291 m/hr +10 kWh.

After a short period, the Model S next to me left. About that same time, I decided to raise my charge limit from 84% to 90% which I did through my app.

After both of these things occurred, my car was then showing 32 kW 138 m/hr +25 kWh.

I don't fully understand these numbers, but to me that seems like my charging slowed down? I did only have a few minutes left on the charge at that point.

And for data sake, it took about 20 minutes to go from 52% to 90%. Total Supercharger cost was $9.88.

Any and all input on these number is appreciated. Trying to learn all this stuff.


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## iChris93 (Feb 3, 2017)

Power Surge said:


> This is an 8 stall station, with the spec showing max 250 kwh (not sure if that unit is correct). I know the stalls are shared 1a/1b, 2a/2b, etc.


Units are kW. 250 kW superchargers, V3, are not shared.

As for the other stuff, it is significantly faster charging from 0-50% then from 50-100%. The charge rate slows as the battery reaches higher states of charge.


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## garsh (Apr 4, 2016)

Power Surge said:


> This is an 8 stall station, with the spec showing max 250 kwh (not sure if that unit is correct).


it's kW (killowatts). Killowatts is a unit of power - a rate of energy transfer.
kWh (killowatt-hour) measures energy. Battery capacity is measured in kWh, but charging is measured in kW.



Power Surge said:


> I know the stalls are shared 1a/1b, 2a/2b, etc. There were 4 cars there already, so I had to share a paired stall with a Model S.


A 250kW supercharger is a V3 supercharger. Supposedly, they don't share power with a paired station like the older V2 150kW superchargers.



Power Surge said:


> I don't fully understand these numbers, but to me that seems like my charging slowed down?


You had two things working against you. First of all, you visited a local supercharger. High-speed charging requires the battery to be warmed up to about 100° F.
When you've been driving for an hour or two, the car's preconditioning can get it to this level pretty easily.
But in your case, the car was too cold, and it just wasn't possible to warm the battery enough. So the lower battery temperature won't allow it to charge at the highest speeds.

Secondly, supercharging slows down a lot as the battery state-of-charge (SOC) increases.
When I'm travelling, I try to arrive at a supercharger with as close to 0% SOC as I dare. You'll only see the full 250kW rate when your battery is really low.
Supercharging will start to drop below 150kW once you've reached 50% SOC, so I generally only supercharge up to about 60% SOC.


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## FRC (Aug 4, 2018)

At a 250kw, if you pull in with 10-15% charge you'll likely see charge rates in excess of 1000mph when it ramps up. That will slow quickly to 500-600 as you approach 50% and quickly down from there to 100 mph as you near 90%. @iChris93 is correct, no pairing involved at 250kw, only at the 150 and 120kw. These are easy to recognize since the 250kw has a much slimmer and lighter cord.

Generally speaking, unless needed for a long road trip leg charging above 80% at a supercharger wastes time and oftentimes money.


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## Power Surge (Jan 6, 2022)

garsh said:


> it's kW (killowatts). Killowatts is a unit of power - a rate of energy transfer.
> kWh (killowatt-hour) measures energy. Battery capacity is measured in kWh, but charging is measured in kW.
> 
> A 250kW supercharger is a V3 supercharger. Supposedly, they don't share power with a paired station like the older V2 150kW superchargers.
> ...


Thanks garsh (and ichris). So everything seems normal for my situation? I wasn't complaining about charge speed, I actually was pretty impressed for the first time trying.

So am I correct in assuming that 32 kW 138 mi/hr +25 kWh means energy (charge) being put into the battery at a rate of 32 kw, adding 138 miles per hour of charge for that rate, and added 25 kWh of energy to the battery pack at that point?


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## Power Surge (Jan 6, 2022)

FRC said:


> At a 250kw, if you pull in with 10-15% charge you'll likely see charge rates in excess of 1000mph when it ramps up. That will slow quickly to 500-600 as you approach 50% and quickly down from there to 100 mph as you near 90%. @iChris93 is correct, no pairing involved at 250kw, only at the 150 and 120kw. These are easy to recognize since the 250kw has a much slimmer and lighter cord.
> 
> Generally speaking, unless needed for a long road trip leg charging above 80% at a supercharger wastes time and oftentimes money.


Awesome, that's good to know. I know the car does show the kw rating of the station, so that should tell me ahead of time if it's a paired station or not. Good to know about the rate of charging also.

I don't plan to use the Supercharger unless I'm going on a trip. I just wanted to give it a try so I know how it all works and make sure there were no issues.


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## garsh (Apr 4, 2016)

Power Surge said:


> So am I correct in assuming that 32 kW 138 mi/hr +25 kWh means energy (charge) being put into the battery at a rate of 32 kw, adding 138 miles per hour of charge for that rate, and added 25 kWh of energy to the battery pack at that point?


That is correct.


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## FRC (Aug 4, 2018)

garsh said:


> That is correct.


Fast learner!!


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## Power Surge (Jan 6, 2022)

How long after charging is completed do the idle fees start?


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## FRC (Aug 4, 2018)

Power Surge said:


> How long after charging is completed do the idle fees start?


5 minutes, but only if the location is 50% or more occupied.


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## Power Surge (Jan 6, 2022)

FRC said:


> 5 minutes, but only if the location is 50% or more occupied.


Does it not apply idle time if there is less than 50% in use?


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## FRC (Aug 4, 2018)

Power Surge said:


> Does it not apply idle time if there is less than 50% in use?


No, it does not. But a warning, you could be the first to plug in, go away, and then have the supercharger fill up while you're gone and incur fees. Years ago, I pulled into a 4 stall supercharger by myself and another car pulled in and plugged in. We were the only two there and we got to talking about our cool new cars, and an hour later we both got hit with hefty idle fees even though we were next to our cars and two stalls remained open the whole time.


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## Power Surge (Jan 6, 2022)

FRC said:


> No, it does not. But a warning, you could be the first to plug in, go away, and then have the supercharger fill up while you're gone and incur fees. Years ago, I pulled into a 4 stall supercharger by myself and another car pulled in and plugged in. We were the only two there and we got to talking about our cool new cars, and an hour later we both got hit with hefty idle fees even though we were next to our cars and two stalls remained open the whole time.


Oof.... good to know


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## garsh (Apr 4, 2016)

Power Surge said:


> Oof.... good to know


The Tesla App should give you a notification when the supercharger becomes 50% occupied and idle fees are in effect. At least, I remember receiving such notifications while traveling & charging.

But notifications appear to be broken in some of the latest versions of the app, so YMMV.


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## MachV (Jan 15, 2019)

Power Surge said:


> This is an 8 stall station, with the spec showing max 250 kwh (not sure if that unit is correct). I know the stalls are shared 1a/1b, 2a/2b, etc. There were 4 cars there already, so I had to share a paired stall with a Model S.


If the station shows 1a/1b/1c as shown in your picture, you are sharing with those stalls. My local supercharger is 6 stalls, where they are labeled 1a/1b/1c and 1a/2b/2c because they essentially share (2) 250kW chargers. I pulled into my local 250kW station yesterday with 19% and the max rate I ever got was 77kW because it was full and showing a Long wait. if I charge at midnight when its empty, I get the full 250kW because its not sharing. Still, it takes less than an hour on a 75kwh M3, which is much faster than the 6kW chargers at Whole Foods.

(I hope) There are not many 250kW stations like this, but they do exist. 250kW is shared between the 3 chargers. Many people don't know this because they have only used their local supercharger(s). It will send more power to the lowest charged car and less to the more charged cars, which is also consistent with normal charging dynamics. But the max between the 3 cars cannot exceed 250kW. If the other 2 cars are almost full, then you might get something approaching 200kW. If you have 50%, and the other 2 shared cars are very low, your charge rate will suffer.


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## FRC (Aug 4, 2018)

MachV said:


> If the station shows 1a/1b/1c as shown in your picture, you are sharing with those stalls. My local supercharger is 6 stalls, where they are labeled 1a/1b/1c and 1a/2b/2c because they essentially share (2) 250kW chargers. I pulled into my local 250kW station yesterday with 19% and the max rate I ever got was 77kW because it was full and showing a Long wait. if I charge at midnight when its empty, I get the full 250kW because its not sharing. Still, it takes less than an hour on a 75kwh M3, which is much faster than the 6kW chargers at Whole Foods.
> 
> (I hope) There are not many 250kW stations like this, but they do exist. 250kW is shared between the 3 chargers. Many people don't know this because they have only used their local supercharger(s). It will send more power to the lowest charged car and less to the more charged cars, which is also consistent with normal charging dynamics. But the max between the 3 cars cannot exceed 250kW. If the other 2 cars are almost full, then you might get something approaching 200kW. If you have 50%, and the other 2 shared cars are very low, your charge rate will suffer.


I've used dozens, if not hundreds, of different superchargers across North America and have never encountered this to the best of my knowledge. And on the face of it, this flies directly in the face of everything I've learned about supercharging from Tesla. Can you tell us exactly where this supercharger is located? I'd like to try to educate myself further. Thanks.


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## garsh (Apr 4, 2016)

MachV said:


> My local supercharger is 6 stalls, where they are labeled 1a/1b/1c and 1a/2b/2c because they essentially share (2) 250kW chargers..


Tesla didn't design V3 Superchargers to share like they did the V2. But I've run into problems with some V3 locations where my car refuses to charge faster than the speeds you mention, even though I was the only other vehicle present and I tried several stations within the location. I think this behavior is more likely due to an issue with the electric feed to that supercharger location.


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## garsh (Apr 4, 2016)

garsh said:


> But notifications appear to be broken in some of the latest versions of the app, so YMMV.


FYI, I've split off the "app notifications" sub-discussion into a separate thread.

https://teslaownersonline.com/threads/app-notifications-no-longer-working.21401/


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## MachV (Jan 15, 2019)

FRC said:


> I've used dozens, if not hundreds, of different superchargers across North America and have never encountered this to the best of my knowledge. And on the face of it, this flies directly in the face of everything I've learned about supercharging from Tesla. Can you tell us exactly where this supercharger is located? I'd like to try to educate myself further. Thanks.


Pearl City Mall - Aiea, Hawaii. (Honolulu). I was dubious and dissapointed too. But at least there is a supercharger now. Cost is $0.44/kWh. Which is cheaper than the 2 slower level 3 Chademo at $0.57/kwh, hosted by the power company. Always full with a waiting line. 6 chargers, 250kW labeled 1a/1b/1c and 2a/2b/2c. Honolulu opened Christmas 2021. The permit was for 12 stalls, but they couldn't make it happen so this is "Temporary". The Tesla engineers had to make custom modifications to this station, probably because they could not get enough amperage capacity. No outer islands have superchargers, except Lanai which Larry Ellison owns 98% of including "his" chargers.

Traveling the USA, supercharging under the Linq in Las Vegas is my favorite - its a real 250kW , 24 stall, non shared. Also Henrietta TX was fun to see the animatronic dinasaurs. I also liked when the superchargers were in covered spaces in a mall. That way you have some window shopping time while charging, and abundant facilities. Looking forward to checking out the new 50+ stall locations soon.


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## Power Surge (Jan 6, 2022)

Ok, I did a second session at the same local Supercharger. This time the car was at 18%. There were less cars there, and I used a stall that did not have a matched stall in use. Still not sure if this station has stall matched pairs, because some people say it shouldn't if it's a 250kw station, and some people say it does since it's got matched stall numbers.

This time it started out charging at 104kw and 444mi/hr. Slowed down to about half that towards the end. What really surprised me was how fast it charged. I went inside and got a sandwich and drink and sat outside and before I was even halfway through the sandwich, my phone notified me that charging was close to done. Maybe 20 minutes total to go from 18% to 85%. 

Also, I met a guy at the Tanger Outlet mall this morning to pick up a part I bought. I noticed the were installing Volta EV fast chargers.


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## FRC (Aug 4, 2018)

Power Surge said:


> Ok, I did a second session at the same local Supercharger. This time the car was at 18%. There were less cars there, and I used a stall that did not have a matched stall in use. Still not sure if this station has stall matched pairs, because some people say it shouldn't if it's a 250kw station, and some people say it does since it's got matched stall numbers.
> 
> This time it started out charging at 104kw and 444mi/hr. Slowed down to about half that towards the end. What really surprised me was how fast it charged. I went inside and got a sandwich and drink and sat outside and before I was even halfway through the sandwich, my phone notified me that charging was close to done. Maybe 20 minutes total to go from 18% to 85%.
> 
> Also, I met a guy at the Tanger Outlet mall this morning to pick up a part I bought. I noticed the were installing Volta EV fast chargers.


If it's the one at the WaWa, it's 250, and unpaired.


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## garsh (Apr 4, 2016)

Power Surge said:


> Ok, I did a second session at the same local Supercharger.


Unless your car's already at 100°F, you're not going to see the really good supercharging speeds. The battery needs a lot of time to get warmed up to that ideal charging temperature.


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## Power Surge (Jan 6, 2022)

FRC said:


> If it's the one at the WaWa, it's 250, and unpaired.


It is!


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## Power Surge (Jan 6, 2022)

garsh said:


> Unless your car's already at 100°F, you're not going to see the really good supercharging speeds. The battery needs a lot of time to get warmed up to that ideal charging temperature.


I actually thought that was pretty damn fast, lol. I did start preconditioning about 45 minutes before charging. Is there another way to go into preconditioning mode besides choosing a station via nav?


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