If you fast charge, Tesla will permanently throttle charging

[Canuck]

I think you missed the hypothetical. If your employer provided a fast charger and you commuted 30-50 miles to work every day, why wouldn't you take advantage of the perk? Tesla has never disclosed that fast charging degrades your battery differently than using a home AC charger.

Good point on the employer provided Chademo. I never thought of that.

I don't think fast charging degrades the battery any faster because of the active thermal management and the stats to date bear this out. In fact, the batteries seem to do better with fast charging.

My guess is the vehicle does not differentiate between fast charges and treats them all as supercharger charges, so he's been throttled back due to excessive use and not out of concern for the battery. That's just my guess though. I just don't see any evidence that fast charging can cause battery degradation over 30% which seems to be the threshold for replacement during the warranty period.

 

[AnxietyRanger]

Good point on the employer provided Chademo. I never thought of that.

I don't think fast charging degrades the battery any faster because of the active thermal management and the stats to date bear this out. In fact, the batteries seem to do better with fast charging.

My guess is the vehicle does not differentiate between fast charges and treats them all as supercharger charges, so he's been throttled back due to excessive use and not out of concern for the battery. That's just my guess though. I just don't see any evidence that fast charging can cause battery degradation over 30% which seems to be the threshold for replacement during the warranty period.

I agree it is possible CHAdeMO charges are being lumped together with higher-powered Supercharges. That said, some reason is making Tesla do this. Fear of something breaking, obviously. What is it? And why again the cloak and daggers. Was it a surprise? A new limiter? Or has it always been this way?

I'm leaning on a new thing (that Tesla added counters/limiters for due to gained experience/data) that is just now coming to light...

 

[bonaire]

CHAdeMO is like 1/2 C charge rate. That is hardly "fast charging" of a Li-Ion battery in today's Li-Ion world..

 

[No2DinosaurFuel]

I think you are a bit confused about the meaning of electrical terms.
Kilowatts is in fact the measure of how much electrical energy you are receiving at the moment; analogous to gallons per unit time of liquids. That is why your battery capacity is rated in kWh, the electrical analogue of gallons of gasoline in your tank.
Amps is a measure of current; analogous to size of a water pipe.
Volts is a measure of electrical potential; analogous to water pressure.

A certain rate of kilowatts of power flow can be achieved by either higher voltage at lower amps (high pressure, small pipe) or lower voltage at higher amps (low pressure, big pipe). Before Tesla changed the display to k/W, we had to mentally multiply the amps by the volts in order to see how fast our batteries were charging.

No I know what kw and amp is. The point of having the amp is if say early in your ownership of the car you see you always start out at 270A. Sure voltage might lower or what not. But later on in the ownership you see you start at 260 always. Guess what? You know they are screwing with the charge current. With KW, it can hide some of this. Say you arrive super low on your SOC. Then your Kw is actually low because your voltage is only 360V or so if you have he 85/90/100kwh battery. But then you start to gain more power as your voltage goes up. My point is voltage is fixed by your SOC of battery, so all you really need is the current. But most people don't know what voltage correspond to what SOC. So I think you analogy of the current as pipe size is incorrect. Current is the flow rate of the electrons not the pipe size. I agree voltage is like the water pressure.

You can probably still get the amp out of the kw but it is harder unless you know the instantaneous voltage. Tesla should make it so you can see the current you starting with.

 

[Canuck]

I agree it is possible CHAdeMO charges are being lumped together with higher-powered Supercharges. That said, some reason is making Tesla do this. Fear of something breaking, obviously. What is it?

My guess: The energy from Superchargers is paid by Tesla and it adds up fast when someone is supercharging (or what appears to be SC) excessively. So excessive users get throttled back to discourage this practice.

 

[AnxietyRanger]

My guess: The energy from Superchargers is paid by Tesla and it adds up fast when someone is supercharging (or what appears to be SC) excessively. So excessive users get throttled back to discourage this practice.

Oookay... I'm not sure which is worse.

 

[SageBrush]

If you go to your second home every weekend that needs one-two DC charges each way,

So every weekend of every year your hypothetical Tesla owner drives 400 - 600 miles each way.

Come ON. I'm sure you can come up with something a bit more realistic

 

[Electroman]

The funny thing is, if the algorithm simply calculates the resistance level and various other parameters and throttled the rate of charge, none of you would be questioning it. Because it already is happening today for SoC above 50%, high ambient temps, position of moon, etc.. Somehow maintaining a counter, brings all the pitchforks.

Tesla could very well do that.. let your battery naturally degrade after a large number fast charging and then as the cell resistance increases, throttle down the charge rate. But instead Tesla is being proactive to avoid such degradation by maintaining a counter (assuming it does maintain one). Thats a great proactive strategy to give us a long battery life with minimal degradation and a great range for years to come.

This is exactly the kind of amazing innovation I have come to expect from Tesla. My opinion of them is a notch higher now.

 

[thefortunes]

My guess: The energy from Superchargers is paid by Tesla and it adds up fast when someone is supercharging (or what appears to be SC) excessively. So excessive users get throttled back to discourage this practice.

But this isn't happening to older cars - we have multiple examples in this thread of much higher SuC use than the OP without throttling.

 

[David29]

Earlier, someone suggested that it would now be a good idea to check if the car's charging rate is restricted before purchasing a CPO vehicle. One might also want to do that before buying an inventory car that has been used as a demonstrator or loaner, too, I suppose.

But another aspect for people who lease is to check on your own car at the end of a lease before deciding whether to buy your car at the guaranteed lease price. In my own case, because I live in a condo, it took me a year to get permission and install my own charger. So in my first year the overwhelming majority of my charging was at a nearby Supercharger. I did also use L2 chargers when I could.
In any case, if I am inclined to buy out my lease car, I might think twice because of the possibility that the car would get restricted charging earlier than it would otherwise, and indeed might also be restricted.

 

[Lloyd]

Earlier, someone suggested that it would now be a good idea to check if the car's charging rate is restricted before purchasing a CPO vehicle. One might also want to do that before buying an inventory car that has been used as a demonstrator or loaner, too, I suppose.

.

That would be another indicator of battery health.

 

[AnxietyRanger]

So every weekend of every year your hypothetical Tesla owner drives 400 - 600 miles each way.

Come ON. I'm sure you can come up with something a bit more realistic

It doesn't have to be 400-600 miles to need two-three DC harges, that much is obvious. Have cold weather and motorway speeds and its half that. Have time-limited DC chargers and you'll be stopping more often. It was an example I use because one close colleague of mine does exactly that. Not in a Tesla, though, but in an ICE.

Look, you can keep dismissing my examples if you want, but the point is - and I think even you agree if you really think about it - 300 DC charges is hardly a very big amount. It is something that a regular long-distance travelling Tesla driver can reach during a normal lease period, so within what I guess most would consider a "new car".

If that's all it takes to start DC throttling (it can be even a smaller number, we don't know when OP got his limitation exactly), that's not a very good thing. It is not like this number would be some completely out there, never gonna run into it thing.

Again, as said, some people have DC chargers in their homes.

This needs to be specified and disclosed by Tesla.

 

[gabeincal]

My guess: The energy from Superchargers is paid by Tesla and it adds up fast when someone is supercharging (or what appears to be SC) excessively. So excessive users get throttled back to discourage this practice.

This would be a very shortsighted scenario..

 

[No2DinosaurFuel]

Tesla certainly never promoted that owners use fast charging primarily.

Not exactly promoting it but if you look at their most recent blog post they are now opening to that exact idea.

Charging Is Our Priority

 

[AnxietyRanger]

The funny thing is, if the algorithm simply calculates the resistance level and various other parameters and throttled the rate of charge, none of you would be questioning it. Because it already is happening today for SoC above 50%, high ambient temps, position of moon, etc.. Somehow maintaining a counter, brings all the pitchforks.

Tesla could very well do that.. let your battery naturally degrade after a large number fast charging and then as the cell resistance increases, throttle down the charge rate. But instead Tesla is being proactive to avoid such degradation by maintaining a counter (assuming it does maintain one). Thats a great proactive strategy to give us a long battery life with minimal degradation and a great range for years to come.

This is exactly the kind of amazing innovation I have come to expect from Tesla. My opinion of them is a notch higher now.

Even if one would agree (I don't), disclosing this would be important. Put it in public specs and let people decide what to think of it.

 

[AnxietyRanger]

Not exactly promoting it but if you look at their most recent blog post they are now opening to that exact idea.

Charging Is Our Priority

I have a hard time reconciling this quote form Tesla and this thread about the dangers of DC charging:

In addition, many sites will be built further off the highway to allow local Tesla drivers to charge quickly when needed, with the goal of making charging ubiquitous in urban centers.

 

[ahaer]

My car is a 2015 P90DL. At the battery level, all charges are DC (they have to be), but DCFC (Superchargers included) bypasses the converters and directly charges the batteries at a high charge rate. L2 and HPWC chargers go through the AC to DC conversion at a much slower rate.

To be clear L2 and HWPC are NOT chargers, they are simply safety switches that communicate with the charger in the car to assure a safe connection before allowing AC power to flow. I remember descriptions that the early supercharges were built by wiring up 12 of the chargers from the car in parallel in the cabinet. So as you say the only difference between AC charging and DC charging is the location of the chargers (internal or external) and the amount of DC power delivered.

 

[Saghost]

Well, I guess this explains why I've not been able to top 87kW at Superchargers this year and normally hover around 60kW or 70kW. Last fall I could hit 110kW or more. I have a May 2016 75D. I've contacted Tesla about this and now their dreaded response of "your car is operating as intended and within spec" seems inevitable. :-/

Are you sure? I've never seen a small battery car go that high - certainly my X never goes past 97 kW.

The lower system voltage results in less power for the same current...

 

[Canuck]

This would be a very shortsighted scenario..

Not really since it only applies to an extremely small percentage of owners and I'd wager a bet that the vast majority of owners would agree with it since it will discourage this practice thus keeping SC'ers more likely to be open when travelling.

But this isn't happening to older cars - we have multiple examples in this thread of much higher SuC use than the OP without throttling.

Do we? I thought we had no other examples where there was no AC charging in addition to the excessive SC'ing, which may be the distinguishing factor in the OP's case.

If you go to your second home every weekend that needs one-two DC charges each way, that's already like 150 DC charges a year. 300 is perhaps two years worth, maybe halfway through your lease. This is not a massively huge number, if you do any regular long-distance travel.

I go to may cabin most weekends with a supercharger half way (they put that in about 2 years ago) that I have used a lot. Not 250 times though. I don't see any throttling back, and I don't anticipate I ever will, since on weekdays I charge at home. That's what I see as the difference. Again, this is all just pure speculation on my part but it's the only way I can make sense of the OP's scenario.

 

[NerdUno]

Of course Tesla could alleviate all the speculation in about 5 seconds unless they have something to hide.