Slow charging at superchargers

[ivolvo]

I have a Tesla Mode 3 long range 4WD for a little over a month and charged it primarily in the garage and didn't have any problems. However, all my experiences charging at superchargers (3 times so far) revealed a slower than expected rate: no more than 40KwH which makes Tesla a barely usable during long trips. I am still not sure: is something wrong with my car; was I unlucky to charge at faulty or not fully functional stations or something else. The charging conditions in all cases were normal: at least 50 degrees, fully warmed car at 20-50% charge, not overcrowded charging stations.
All my attempts to find from Tesla technical personnel how normal it was ended up with non-committal assurances that charging rates vary? how much? they would not answer. I visited a Tesla dealership in Chicago downtown anticipating that I could compare my car charge rate with one that is already there. no luck: they claimed that their stations are old and slow and I would not see much difference. I have a few questions hoping that this forum could help with:

1. How typical this experience is, are my expectations that are under normal circumstances the charge rate ion 135kwh stations should be close to 120kwh which should result in 30 minutes charge for my long range model 3 from 10% to 90% charging
2. What rates people usually observe
3. How to verify that it is not my car fault
4. What pressure I could apply to Tesla to check the car

The other issue: the discharge rate on highways is about 30% faster than the car predicts. I realize that battery depletion depends on many circumstances but I would at least expect that software would detect the existing rate and adapt predictions accordingly. Otherwise, it is an outright unreliable number that one should correct in their head predicting how far she could go before a battery is dead. By exaggerating charge time and underestimating the discharge rate, Tesla plays the way all automakers do. I hoped they would be different for the sake of trust and a good customer relationship. A little disappointed although driving itself and car handling is a lot of fun.

 

[Kermee]

I'm 99% sure your slow Supercharging rates are due to a "cold" battery. Next time, try Supercharging after a long drive so the battery is properly warmed up to a much higher temperature.

At 50F, my Model 3 starts Supercharging at 28kW and stays there for about 20 minutes. It takes almost a full hour for it to hit 122kW if the SoC allows it.

Welcome to Fall/Winter, Tesla EV style.

 

[ewoodrick]

You are never going to get 10-90% in 30 minutes.A Supercharger is definitely going to slow well before 90%
It's going to be over an hour to get to 90%

 

[TexasEV]

Some thoughts:
1. Cold battery. When you supercharge after driving an hour or more on the highway at those SOC you’ll be getting much higher rates. Don’t worry about it. By the way 50 degrees is not warm. Except maybe in Chicago.
2. The range shown on your battery meter is not “predicted”. It’s the EPA rated range, meaning it’s the range when driven on the EPA test cycle. If you don’t think it’s accurate, blame the EPA, not Tesla. For predicted range based on your most recent 5, 15, or 30 miles of driving look at the energy app display. Your actual range is determined mostly by speed and temperature. Also using the car heater greatly increases your energy consumption. Use the seat heaters mostly which have negligible impact on range. Even in the best case in winter you’ll get less range, but it doesn’t matter in this car— you’ll have more than enough range to get to the next supercharger on a road trip.
3. Whether a supercharger is crowded or not is irrelevant. It only matters if another car is charging at your paired stall.

 

[ivolvo]

Thanks, this is interesting and none was given to me at the dealership when I came with these questions. Good to know about after long drive faster charging. BTW, I drove about 20 minutes before charging, I thought that it is enough for everything to warm up.

> The range shown on your battery meter is not “predicted...
So be it. My point is that to show permanently on the screen something that carries no useful information is senseless. The valuable space should be filled with information a driver could use to make informed decisions (e.g. do I need to stop here for recharging or wait until the next station). A car could predict based on current use how long it would last if conditions don't change. And typically they don't.

> Whether a supercharger is crowded or not is irrelevant. It only matters if another car is charging at your paired stall.
I was also surprised when I was told this at Tesla downtown dealership. 2 out of 3 guys I talked to were completely clueless; the 3-rd knew a little bit more and that's what he told me. BTW, how do you know which stalls are paired? And they could not be more than paired, right?. There were 3 out of 8 used stalls in one case and 2/8 in another including my car. So the chances of pairing are not that high. but the temperature conditions that you mentioned could be the cause.

 

[ivolvo]

I'm 99% sure your slow Supercharging rates are due to a "cold" battery. Next time, try Supercharging after a long drive so the battery is properly warmed up to a much higher temperature.

At 50F, my Model 3 starts Supercharging at 28kW and stays there for about 20 minutes. It takes almost a full hour for it to hit 122kW if the SoC allows it.

Welcome to Fall/Winter, Tesla EV style.

Thanks, would charge now on arrival after a long trip

 

[ivolvo]

Are there any indications about battery conditions to receive charge? or you should rely on your experience and see it for yourself at a charging station?

 

[TexasEV]

You’re overthinking this. By the time you need to stop at a supercharger on a trip, your battery will have warmed up enough to take whatever power it can take at that SOC. Really I’ve driven Model S and now Model 3 for almost 6 years, on several 1500-3000 mile trips, and it’s just never been an issue. You’ll also get to know how to judge distance based on rated miles, or if you use nav your projected SOC on arrival does take your recent energy consumption into account.

Look at the stall numbers to see pairing. Search this forum for paired stalls for details, lots of posts explaining it.

By the way it’s not a dealership. It’s a Tesla store. And best to search here for answers rather than asking the sales staff, most of whom don't drive the car except for brief test drives and can be a fountain of misinformation.

 

[ivolvo]

You may be right: fears of a novice. Thanks for the information. I already learned here more than in any Tesla official postings and personal discussions with their employees (although I talked to technicians, not salespeople).
Maybe you also know where I could see and discuss UI related issues. Is there a place that Tesla UI design people look at suggestions? There are so many things that could be improved in that area.

 

[Rocky_H]

@ivolvo You have some good new beginning questions. And yeah, it's just kind of an unfortunate symptom of Tesla's insanely fast growth that they are having to hire tons of new people very quickly, so there is some training, but they just can't know what it is like to use a Tesla daily in all kinds of conditions like owners do. So, specific answers:

Yeah, on long trips, the slow charging shouldn't be an issue, because your battery will already be warm. And yes, you definitely figured that part out, that if you won't have overnight charging at a hotel, it would suck to let the car sit out overnight below freezing and then try to Supercharge first thing in the morning. I did a 5,000+ mile trip in February, and I would go to the Supercharger when I got into the city for at least some 20 minutes or so, to get most of the charge on that really fast rate before heading to my AirBNB.

So your experiences of driving 20 minutes to a Supercharger in the morning, and it's currently 50 degrees... That's still some fairly cold conditions. A 1,000+ pound chunk of metal doesn't warm up quickly just from the outside air temperature, so that battery was probably still 40 degrees or less, which is pretty cold for charging. To get near 100kW charging power, the battery needs to be toasty.

And the pairing: Each number is a stack of the charging hardware, and the A and B sides share that. The layouts are different at different sites, though, so they aren't always next to each other. Some sites are like 1A 2A 3A 4A 1B 2B 3B 4B, so the paired ones could be three spaces apart or something.

About the "miles" usage rate. It's called "rated miles" for a reason. That is exactly according to the EPA rating for their test procedures, which are pretty mild driving and not heating or air conditioning. Most people fall short of EPA mileage ratings in most of their cars anyway; that's pretty common. I think the thing that is catching you off guard is the heating factor with electric cars.

With gas cars, they are always desperately trying to vent waste heat. They generally waste about two thirds of the energy of the gasoline out the tailpipe and radiator and engine block. They are just horribly inefficient. Well, the "upside" of that is that heating the cabin from a gas car is always "free". You can pipe some of that waste heat inside. Electric motors, though, are something like 90% efficient. They are amazing! But that means they don't have "free" waste heat to warm you up inside the car. So they are basically having to run an electric space heater to warm up the inside of the car, and that all comes from the same battery. So you are shocked that the "miles" are running down quickly, but you need to realize that the same battery is supplying "miles" + "heat". The rated miles number is just a different unit for showing how much fuel is there. Some people say to just switch it to % to not be bothered, but I can't think in terms of "It's XX% to Jeff's house." So I keep it on miles, but just mentally know that it's ballpark a bit too high of a number versus real.

 

[Electric700]

Ivolvo, did you try moving over to the next Supercharger connector when you noticed the slower charge rate? If not, that's something to try.

Sometimes the Superchargers do have issues. Try calling the number listed on one next time you notice a slower charge rate: (877) 798-3752.

If the issue persists, you may want to reach out to [email protected]. They can access your car's logs as well.

 

[ivolvo]

Thanks, @Rocky_H, it is extremely useful. I agree (or accept rather) all you've said except this battery display thing. EPA ratings are theoretically useful and should be published on paper. In a car, you need to see information that helps you to decide what to do. Why not delegate this tedious job to a computer and it will give you meaningful suggestions based on your destination, current usage rate and other factors instead of a person making their error-prone calculations in their head. Maybe a car does it for you on trips and you are not aware of it?

 

[ivolvo]

Thanks, @Rocky_H, it is extremely useful. I agree (or accept rather) all you've said except this battery display thing. EPA ratings are theoretically useful and should be published on paper. In a car, you need to see information that helps you to decide what to do. Why not delegate this tedious job to a computer and it will give you meaningful suggestions based on your destination, current usage rate and other factors instead of a person making their error-prone calculations in their head. Maybe a car does it for you on trips and you are not aware of it?

I meant: I am

 

[DR61]

ivolvo, (love the screen name...) excellent questions; I am also a newer owner (2 1/2 months). It has been fairly warm here so far so I haven't had the problem of heating the battery and car interior, but I did have an interesting experience on a trip I took recently. On the trip south down the Sacramento Valley, I got exceptional range due to a constant north wind. Coming back up north, I set the Nav system for home and it indicated I would get back with 20% charge left. I started driving and with after 30 min. going into the high north wind, I got an advisory message on the screen that I should consider stopping to supercharge at Corning, about 50 miles south from home. The estimate of remaining charge had gone down to 8% at arrival. It worked out fine to stop as I appreciated the break. So setting the Nav destination is really a good way to get a reliable real time estimate as you drive on the battery range.

I also tried bringing up the new energy app, that is also very informative about real time range.

As an aside, that high north wind a few days later figured greatly in the ongoing Camp Fire disaster. Thankfully the winds have died down now.

 

[ivolvo]

ivolvo, (love the screen name...) excellent questions
...
I also tried bringing up the new energy app, that is also very informative about real time range.

As an aside, that high north wind a few days later figured greatly in the ongoing Camp Fire disaster. Thankfully the winds have died down now.

No Volvo affiliation, just happened that my first name starts with 'I' and last name with 'Volvo' What is an energy app?

 

[GregRF]

Thanks, @Rocky_H, it is extremely useful. I agree (or accept rather) all you've said except this battery display thing. EPA ratings are theoretically useful and should be published on paper. In a car, you need to see information that helps you to decide what to do. Why not delegate this tedious job to a computer and it will give you meaningful suggestions based on your destination, current usage rate and other factors instead of a person making their error-prone calculations in their head. Maybe a car does it for you on trips and you are not aware of it?

The car does this computation for trips. If you use the navigation it will take into account current usage and tell you what your expected destination battery level will be. Alternatively you can also see this using the Trips tab in the energy graph.

Here is a supercharging graph to help set your expectations:

source

On a recent trip I had a 32 minute charge at an unpaired new charger and went from 8% to 76%:

 

[TexasEV]

Thanks, @Rocky_H, it is extremely useful. I agree (or accept rather) all you've said except this battery display thing. EPA ratings are theoretically useful and should be published on paper. In a car, you need to see information that helps you to decide what to do. Why not delegate this tedious job to a computer and it will give you meaningful suggestions based on your destination, current usage rate and other factors instead of a person making their error-prone calculations in their head. Maybe a car does it for you on trips and you are not aware of it?

It does. That’s what the energy app does (based on past 5, 15, and 30 miles of energy use) and that’s what the nav does when it estimates percent charge at destination. Please try not to be offended, but have you RTFM?

 

[DR61]

No Volvo affiliation, just happened that my first name starts with 'I' and last name with 'Volvo' What is an energy app?

I was just thinking of my high school Latin, and translated 'I ROLL'. The energy app is new to software release 39.x I think. On the bottom line of display next to the music icon there is a new icon; it will show a box with a number of apps including Energy, games, and a web browser.

 

[Big Earl]

Thanks, this is interesting and none was given to me at the dealership when I came with these questions. Good to know about after long drive faster charging. BTW, I drove about 20 minutes before charging, I thought that it is enough for everything to warm up.

> The range shown on your battery meter is not “predicted...
So be it. My point is that to show permanently on the screen something that carries no useful information is senseless. The valuable space should be filled with information a driver could use to make informed decisions (e.g. do I need to stop here for recharging or wait until the next station). A car could predict based on current use how long it would last if conditions don't change. And typically they don't.

> Whether a supercharger is crowded or not is irrelevant. It only matters if another car is charging at your paired stall.
I was also surprised when I was told this at Tesla downtown dealership. 2 out of 3 guys I talked to were completely clueless; the 3-rd knew a little bit more and that's what he told me. BTW, how do you know which stalls are paired? And they could not be more than paired, right?. There were 3 out of 8 used stalls in one case and 2/8 in another including my car. So the chances of pairing are not that high. but the temperature conditions that you mentioned could be the cause.

I highly recommend changing the display to show percent instead of rated miles. I find it to be far more useful. Multiply % by 3 for summer rated range and multiply % by ~2 for winter range.

A full Supercharger station will rate limit ALL chargers to not exceed the maximum capacity of the transformer. I've seen many 8-stall Superchargers on a 500 kVA transformer. At a full load with 8 cars at a low state of charge, each charging station would be limited to 62.5 kW instead of the 72 kW that you would normally see.

 

[Big Earl]

Are there any indications about battery conditions to receive charge? or you should rely on your experience and see it for yourself at a charging station?

The dotted regeneration limit is a very good indication of Supercharging speed. Any dots at all will mean that Supercharger speeds will be significantly reduced. It will take several miles of highway driving after the dots disappear for full speed Supercharging to be allowed (about an hour of highway driving time, in my experience).