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If you fast charge, Tesla will permanently throttle charging

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I think the earlier taper was more of a software update that affected everyone. Because I definitely remember a time when my max rate was low but the taper started late, like 60% ish. Then later the taper started happening before I even got to 50%, but everyone was complaining about that at the time, not just the high mileage people. It was definitely a double whammy though! Would love it if they could reduce the taper with a future software update.
My taper has been later the last few charges, ever since the update that increased peak charging rates a few months ago. The ABRP data very clearly shows a line where the throttling has been reported, but it's only a cut of the peak rate. I think there is a second factor at work, a more subtle one, that is causing an earlier taper. For certain some S cars have ended up with an early taper when the cooling louvers are not working correctly. There may be another subtle fault like that.

And I agree with the other poster. For most people the emotional weight seems to exceed the practical weight.
 
I am still reading through all of the posts, and still just to May 2017. It seems this information was out there for a while. My experience in 2018 when I purchased my MX was about the same as others experienced even before this was known. I did get the unlimited SuC with mine. I have been working with batteries in laptops for years, and set my laptops to only charge to 60% (not all can do this) as they are plugged in 90% of the time. This is to help the Li ion batteries to last longer. Before I leave where I am going to need the battery life, I change it to 100%. I also knew from Samsung phones and laptops with fast charging capabilities that fast charging them can shorten their lifespan (by a small amount). So with this in mind I specifically asked questions about supercharging, charging to 100%, etc. This was in Boston. I was told supercharging was taken care of by the battery management and cooling and wasn't bad to do, that you shouldn't charge to 100% very often unless you really need it and should not leave it at 100% for very long, and then not to go to 0%. I never received a letter from Tesla or anything about supercharging being detrimental. I was given the company line about home charging, and yes, it is very convenient to plug in when I get home and it is charged by the next day.
I have seen and understand about the different factors from the temp, status of the SuC, sharing, SoC, etc. My last trip from MA to VA only had me stopping twice which was fine I have always seen the tapering, and never liked to stop at an urban charger with a 72kw limit, but depending on my Soc at arrival it didn't always seem to be a long difference.

All the AC / DC talk I agree. All input to the batteries is DC and DC is being used to indicate SuC and AC indicating home charging. What the difference is really the rate of charge. 7kw, 14kw, 50kw or 120kw. It would be nice for Tesla to publish (and maybe they have and I haven't seen it yet) that says charging at rates above a certain level would have a more negative affect on the battery.

With the pandemic my travels were stifled for a while. I do have statistics from every charge since receiving my MX. I am going to review my early charging rates, times, and speed. I will continue to read through all of the posts, but I am still very happy with my purchase. I wish I had known about this topic and had been informed. I am not sure it would have changed my charging habits much, but it would have a little. I'll know more after I look at the first 24 months of charging and see if I detect any slow down that is related to over charging. I probably won't have another road trip until November so may not be able to get any more data. If I am topped out at 108-110kw at this time I don't feel I am too affected, but would like to know if this will be dropped to 80 or 90kw at some point. I am also wondering if any of those that feel they have been dropped from 120kw to 80 or 90kw if any software releases increased this for you or if it truly is a chemical limitation.
 
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I don't doubt this...but there are ways to reduce the impact.

Bjorn Nyland has shown the best cross country speeds are to drive down to a lower SoC, and stop charging sooner. Charging past 80% does not make sense unless you can't make your destination with a reasonable margin.
At the time the slower charging really hit, I was traveling from Charleston SC to Cherry Hill NJ periodically. I went from two hours extra on the road for charging to four hours extra. I had to stop at all but one or two of the chargers available at that time, because they were spaced so far apart. Charging to nearly 80% every stop was necessary to make it to the next charger.
Back then navigation was supposed to optimize your charging stops to minimize time, including taking into account time to travel between the chargers and the highway. As chargers were added, I think this optimization was just abandoned. My navigation still wants me to charge to 80% or more on road trips, planning for skipping chargers wherever possible. That tends to maximize, not minimize, travel down time.
 
My navigation still wants me to charge to 80% or more on road trips, planning for skipping chargers wherever possible. That tends to maximize, not minimize, travel down time.

Depends how far from the freeways the SCs are located. I found that if the SCs are right off the freeway exits, it’s a faster overall trip to stop more often to optimize charging to only 50-60% due to the taper after that level.
 
I've read the thread. Far as I can tell, there's currently three distinct populations in the thread. One: people who have some charging problem that prevents high rate charging, such as louver, connector, or cooling system problems. Two: people who have been throttle by Tesla, by chopping off the peak of the rate after high volumes of Supercharging. And three: people who don't understand cold charging or high SOC charging, or other similar problems. This is the smallest group.

The first two both are zero fun for owners subject to them. One is fixable. The other is probably just a reality of these battery packs. In both cases, Tesla's transparency has been rather poor, and I would say that's the biggest issue.

Speaking of the second group: anyone who has been throttled because of high amounts of DC charging, have you seen your rates go up as part of the recent software updates? It's made a big difference on my 90, but I've only done maybe 500 kWh of Supercharging over the life of the car, since most of my charging is at home.

I'm assuming the above summary is reasonably correct. I have a 2013 S85 that has 87k miles. I would guess that <5% of my charging has been supercharging. My supercharging seems to be limited where even under ideal conditions I max out at 75kw and rapidly taper down to the 60s. A year ago I would peak around 110 and rapidly taper down to the 90s in similar conditions.

Is it worth my time to have the car checked by tesla service to see if this is a bad component? Or should I just assume it is a software limit and there is nothing I can do about it? My car is 7 years old so still has 1 year left on the battery/powertrain warranty.
 
That's what I figured. Just wanted to see if anyone had found any hardware issues that were causing slow charging.
The ones that showed up earlier in the thread were around cooling and the charge connector overheating. If your charge connector is staying only slightly warm, the cooling system is smoothly ramping up with cabin cooling still active, and the lower louvers in the front are opening during charging then you are likely just throttled. If the louvers aren't opening up or the connector is quickly getting warm then there could be an issue, but it won't be covered by the battery warranty.
 
The ones that showed up earlier in the thread were around cooling and the charge connector overheating. If your charge connector is staying only slightly warm, the cooling system is smoothly ramping up with cabin cooling still active, and the lower louvers in the front are opening during charging then you are likely just throttled. If the louvers aren't opening up or the connector is quickly getting warm then there could be an issue, but it won't be covered by the battery warranty.

Thanks for that info. Exactly where are the lower louvers? How can you tell if they are open?
 
I think this is normal for all cars.. even those that are not throttled.

charging above 90% takes much longer than charging from 20%-50% and charging above 95% takes FOREVER.
Even assuming that is true that other cars would take an hour and a half — I would guess it isn't — the point I was making is that I need to charge to 95% to have a reasonable shot at longer trip legs. Those driving larger battery cars would never even need to charge that high nor would they need to drive down to 5% or less. Those with larger batteries can also skip Supercharger Stations at times. I can never ever do that on highways with typical Supercharger Station spacing.

So, yes, Supercharging at 95% is pretty slow on any car, however it just isn't needed for most cars on road trips. I hope that those here at TMC, who make road trips, are aware that the fastest way to go is to charge just enough to get to the next Supercharger Station, plus a buffer in case of unfavorable weather or other issues. This avoids most of the taper on most cars and keeps overall Supercharging speeds high. In my car I can only get to a 15-20% buffer on short trip legs so I often make do with 10% or less. (And even a 20% buffer is a lot fewer miles in my car than in a larger battery car, which is something else I have to deal with.)
 
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Here's 11-58% on an S85 for comparison. 30min session.

btx85-gif.581578
 
Yes, this will be the same on any car powered by lithium ion batteries, which is all of them. Charging must slow down as the state of charge increases... It will always be very slow from 90-100%. This is to prevent battery damage.
What you overlook is the speed of the charge from 10% to 90%. On larger battery cars it is much faster than on my car. Even if the speed was about the same above 90%, the overall Supercharging time would be less on the larger battery car. The larger battery car would also be faster in "rated miles" (or kWh) per minute, which is what really matters on a road trip leg.
 
The larger battery car would also be faster in "rated miles" (or kWh) per minute, which is what really matters on a road trip leg.
I'd say that may be true. E.g., the difference between an efficient (Wh/mile) Model 3 and a less efficient (Wh/mile) Model X is in the 50% ballpark so the Model X would need more than 50% more battery capacity for your statement to be true.
 
Agreed. I was only referring to the need to slow down charging at high SoC. If you have a larger battery, then you don't have to charge as high and can get back on the road quicker. Also, smaller cars that use less energy will get more range miles per hour while we are still limited by supercharger kw output. So, that's why the model 3 is the supercharging king. High charging rates, reasonably large battery, and highest efficiency.
 
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I'd say that may be true. E.g., the difference between an efficient (Wh/mile) Model 3 and a less efficient (Wh/mile) Model X is in the 50% ballpark so the Model X would need more than 50% more battery capacity for your statement to be true.
I was comparing different Model S battery sizes. They would have roughly the same efficiency.

It is certainly true that the more efficient Model 3 might charge faster, in miles per minute, than a less efficient Model S or X of somewhat larger battery size, for a given trip leg length. However, I would expect that an LR 3 would charge more quickly than an SR 3, especially for a trip leg approaching the range of the SR (because of the increased taper in the SR).

That is the sort of thing I face frequently in my S-60 because of the limited battery capacity and range, currently about 178 RM. Consider, for example, a trip leg in your area that I have done numerous times: Farmington Supercharger Station to Albuquerque Supercharger Station, 182 miles. It is a tough trip in my S-60! (A Supercharger Station in Cuba would be helpful.)
 
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I was comparing different Model S battery sizes. They would have roughly the same efficiency.

It is certainly true that the more efficient Model 3 might charge faster, in miles per minute, than a less efficient Model S or X of somewhat larger battery size, for a given trip leg length. However, I would expect that an LR 3 would charge more quickly than an SR 3, especially for a trip leg approaching the range of the SR (because of the increased taper in the SR).

Yup. That's true. Road tripping in the S60 going to be take longer because you have to push it to charge to the limit.

Yes, SR model 3 will take longer than the LR model 3.

The LR RWD model 3 is a road tripping beast. When we've gone on trips, it's usually ready to go before I can finish going to the bathroom, drinking some water, and eating a quick snack.
 
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