If you fast charge, Tesla will permanently throttle charging

[AnxietyRanger]

I think ALL cases except one have been on the 90 kWh packs. Since there are many more high mileage, high DC-charged 85s than 90s, I think there's a spesific problem with the 90 kWh packs.

Very likely. Though there is that one early 85D also reporting this (as you too note) with Service Center confirmation. But other than that all reports seem to be 90 kWhs while 85 kWhs have large-mileage reports of no throttling (or at least no early charge throttling, changes in taper mostly unknown). @JRP3 also pointed to some interesting and potentially relevant differences in 85 vs. 90 kWh chemistry.

This is what I think is so great about this community - we have a lot of experts here and after the initial shock of what'sthis/neverheard, we have evolved into finding out as a team.

 

[MrAustraliaTax]

Humour/Sarcasm follows:

NEWSFLASH: Tesla service start removing tyres that have rotated too many times, leaving drivers with 3 tyres instead of 4. When questioned about the practice, a Tesla Service Manager said that "we were finding that drivers were using their tyres excessively and to prevent premature wear we are proactively removing the fourth tyre whenever the tyre use counter reaches a Tesla determined limit."

Forum users on TMC are sharply divided between those lauding Tesla for their innovative and wise preventative maintenance program and those that are unhappy about the resultant performance degradation which they were not warned about when they purchased their vehicle.

End of Humour/Sarcasm

 

[Cloxxki]

There must be multiple factors at play.
Bjorn may never have gotten his car to places that are over 100ºF. His battery may well have seen that from extended towing trips, though. And it's not just the 90kW cap in his case, but also an early dropoff to under 50kW. May be an extra layer of issues many others don't experience? It's not about 5 minutes of time loss on that particular car, seems more to me.

Seems to me from what I read here, that the chemisty (first) used on te 90 packs is disappointing. So little gain in range, so sensitive to fast charging.
Now I'm even more curious which way Tesla will go with the 2170 automotive cells. Fast charge specific, because Model 3 owners will have small batteries and reduced access to slow overnight charging)?

One factor I've not read on here (I did skip pages):
I've once heard that it's not good to charge a batttery fully, and then let it sit at high SOC. With owners reliant on SuC, I can imagine this might be unavoidable to them. They charge then they have time, and might not always be able to time it beffore a ride? Would a battery sitting at 100% for a day affect its range more, and how would that relate to charge speed?

 

[MikeBur]

Interesting / long thread with the usual, expected, viewpoints... hoping Tesla/ @JonMc helps us all understand the counter increment criteria and thresholds on which limits, to help stop the masterdebaters (see what I did there? ;-))

On a separate question: Given that there are numerous counters that affect charging rates permanently based upon use history, has anyone done the determination of potential impact if/when able to charge at Elon's promised >300kW updated SpCs?

 

[sorka]

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.

I've just started this thread, so pardon me if this has already been mentioned, but your battery is the first to introduce Silicon into the anode which is a known Lithium Ion battery degrader. The 90's have already, since the beginning had a faster taper than the 85s and Tesla has never explained how they got around increased degradation by using Silicon. I suspect that they didn't and this is their attempt to mitigate the issues caused by the Silicon enhanced chemistry.

Have any others seen the 90KW limit on 85s(not including the A battery which was limited to 90 KW from the very beginning)?

 

[Matias]

On a separate question: Given that there are numerous counters that affect charging rates permanently based upon use history, has anyone done the determination of potential impact if/when able to charge at Elon's promised >300kW updated SpCs?

Given that the current cars can't even use the full 135 kW of SpCs, I'm sure those faster SpCs are for trucks.

 

[Matias]

Have any others seen the 90KW limit on 85s(not including the A battery which was limited to 90 KW from the very beginning)?

There is one 85 reported in this thread, others are 90s. Since there are many more high mileage, high DC-charged 85s than 90s, I think there's a spesific problem with the 90 kWh packs.

 

[AnxietyRanger]

I've just started this thread, so pardon me if this has already been mentioned, but your battery is the first to introduce Silicon into the anode which is a known Lithium Ion battery degrader. The 90's have already, since the beginning had a faster taper than the 85s and Tesla has never explained how they got around increased degradation by using Silicon. I suspect that they didn't and this is their attempt to mitigate the issues caused by the Silicon enhanced chemistry.

Have any others seen the 90KW limit on 85s(not including the A battery which was limited to 90 KW from the very beginning)?

There is one affected 85D report. See a few messages before #550. Other affected reports 90 kWh or non-affected 85 kWh.

 

[AnxietyRanger]

Given that the current cars can't even use the full 135 kW of SpCs, I'm sure those faster SpCs are for trucks.

And/or Model 3s.

It seems plausible that 2710-using Model 3s would be superior to Model S/X in charging.

 

[sorka]

Yet oddly the studies which have tracked pack capacity and charging types have shown cars which have done the most supercharging to have the least capacity degradation.

Yup, and here's why....

Quoting myself from another thread a few months back:

The answer should be that supercharging degrades battery life but anecdotal evidence is pointing to the opposite. A clue can be found here around minute 6:

In which Dahn says that it's not how fast you charge it but how long it spends charging because more time at raised temperature increases parasitic reactions.

The thermal management will keep the battery from rising above x temperature. If you charge at home at 40 amps on a moderate to warm day, the AC will eventually kick in to cool the battery and keep it at x temperature. Say you charge for 4 hours on an 85 to get a 50% SOC increase. The battery has spent 4 hours at x temperature incurring degradation from parasitic reactions.

Now say you supercharge. The battery should get a lot hotter, right? Not necessarily. The thermal cooling will kick in at a much higher rate when needed to keep the battery at the same x temperature threshold. So now you've only spent 20 minutes for the same range and same battery temperature vs 4 hours at 40 amps.

He clearly states that it's not the rate at which you charge but how long the battery stays warm from charging. So if you can charge fast and use energy to keep the battery cool, it will last longer than if you spend more hours charging the battery at the same temperature regardless of the charge rate.

Note, I'm comparing a moderate charging speed in moderate to warm weather to supercharging. Charging at 1.2KW from 110v will not result in any consequential battery temperature increase so that would be the best way to treat the battery even though it takes 1.5 days to get the same 50% increase in SOC.

I guess what I just said is that I think charging at moderate speeds causes the most degradation while supercharging or super slow charging causes the least.

So what I want to say is, no don't supercharge because you'll ruin your battery but I suspect it's not even remotely true.

So instead I'm going to say, be responsible and don't locally charge especially if there's a line of people who are passing through on long distance trips. I can't STAND local chargers because here in the Bay Area, most of the folks charging are doing so to save money from charging at home.

Tesla's change in unlimited couldn't come fast enough for new cars and idling policy for all cars. Hopefully they will tighten down the free for life to actually enforce the "for long distance travel" disclaimer that they put on their site back in early 2015. I suspect those that bought befor ethen won't have to adhere to a "long distance only" charging policy since Tesla's didn't say "for long distance only" prior to that.

 

[sorka]

The original post said replacement at 7%. I said more like 30% and then I used Nissan as an example and I used "~" ("approx") to arrive at 37.5%. I'm off by 3.75%. That's approximately to me!



You're using the Leaf as an example of having clear guidelines for battery replacement when it only came about after a class action lawsuit was certified?

CARB (In California) forced Nissan to replace Leaf batteries when they got to 70% of original capacity.

 

[RubberToe]

How about if Tesla released the source code that controls the cars charging? Doing that and not allowing anyone to modify the actual executing code answers the question more thoroughly than any verbal description.

Can't someone here who has hacked into the code just post it?

RT

 

[sorka]

Can't blame the OP for assuming using Fast DC charging is safe. I have know for years that high C-rate charging was bad for batteries, but not every Tesla owner even knows what that means.

But only because of high temperature. If you're actively cooling the batteries during charging to keep the temperature down, then it's nowhere near as bad as charging slower at the same temperature. There's very little difference in battery temperature when charging at 80 amps vs 100KW yet the batter stays hot for a lot longer when charging at 80 amps for the same kWH charge vs charging at 100KW.

 

[sorka]

Would be interesting to know why some 85's seem to be getting fast charging, possible at very significant capacity losses. Might those be top end cutoffs of sorts? Or huge heat losses making for effectively reduced charging rates anyway?

I wonder if it's more than a simple counter? Perhaps it's counter combined with a ratio and if the ratio of dc faster charging to slow charging remains small that it doesn't restrict you even if you exceed the simple counter? Or perhaps the ratio effects the weighting of the counter changing the abosolute count limit based on the ratio.

 

[sorka]

Ok, no way I'm going to be able to read all the posts. Could someone kindly post a checkpoint summary of the major facts of this thread so far

 

[zambono]

Tesla explains why it limits Supercharging speed after high numbers of DC charges

How is this going to work if they want to expand supercharger access and encourage use for local driving?

 

[WarpedOne]

What is the limit?

Without exact numbers this is pure FUD.

 

[Matias]

Here is 43 pages thread about the subject

If you fast charge, Tesla will permanently throttle charging

 

[MrAustraliaTax]

Ok, no way I'm going to be able to read all the posts. Could someone kindly post a checkpoint summary of the major facts of this thread so far

If you DC fast charge a 90kWh pack too much the charging rate slows down a bit because of a Tesla counter.

The rest is speculation and extra detail surrounding the above core fact.

 

[ODE90D]

If you ask me it is obviously a 90 kWh battery issue - and not a SuC counter thing as the “old” batteries with far more Supercharging are not affected. I wouldn’t be surprised if the peak on the 90Ds continues going south as the car ages because there is a problem with the new silicon anode and Tesla is doing this to avoid rapid degradation leading to warranty issues. So far my peak is reduced by approx 20% after 100.000 km in my 90D. Just wait for more high milage 90 kWh batteries and we will see that practically all are throttled.

For quite a while I have been asking for detailed SuC data from other Tesla owners in this forum, in the Danish teslaforum.dk, the Danish Facebook group and at Superchargers. Although the number of contributions to this analysis is low I have yet to come across something that contradicts my theory that only 90D are affected. You can view and enter data of your own here : Tesla Supercharging Speeds