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Tesla may have fast charging hard cap, Supercharging speeds permanently reduced

9481 Views 77 Replies 22 Participants Last post by  Steverino

An owner of a Model S has received official confirmation from Tesla that ALL Tesla's now have a hard count of how many fast charging sessions are allowed (Supercharging OR via CHAdeMO adapter). Once the hard count is reached, max Supercharging speeds are PERMANENTLY reduced FOREVER.

Wow! If I was a Tesla owner I'd be pissed! Never being told about this restriction up front. Supercharging not what it used to be, eh?
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That certainly won't help resale value (*permanently gimped Supercharging).
This hard capping of max SC speeds was brought up previously on TMC too:

<deleted taunting>
thread re-opened (at least until more is learned about this potential issue/practise)
But please keep it civil people
Thanks. I'm waiting on my 3rd contact to verify, but he chuckled when he understood the question. He said he would have seen it pop on on a ton of cars, well before this week.
If this was a new change, he probably would chuckle since he's far away from the mothership and probably doesn't even know it happened yet.

What we know for sure is that a 2015 P90D owner has experienced degraded Supercharging, and a Tesla engineer in MO documented that the degraded SC rates are normal and that the owner's Tesla has had Supercharging ability PERMANENTLY REDUCED. There is no disputing those facts.

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And op also said he used to get 115. 90<115 last time I checked.

Tesla Bjorn has also confirmed his S has suffered SC rate neutering.
And op also said he used to get 115. 90<115 last time I checked.
That is why I stated current in this statement: "The OP claims he is current getting 90kW charging."

If true, then again how much extra time would this take him to actually charge?
25 kW is 25 kW. Because it's only realized for 5-10 minutes a charge session, it's okay to be taken away? I guess you would be fine if Tesla pushed out a firmware update reducing HP by 50 to increase power train life too, huh?

The main point of contention is that Tesla is doing these under the hood changes without telling their customers. When's the last time GM or anyone else put out an update that reduces the speed someone can fill their gas tank?
So you are ok with Tesla downgrading performance without informing customers beforehand if it's in the name of reducing failures (and warranty expenditures).
Oooooook, Tesla is lucky to have such understanding customer's as yourself.
You are not acknowledging my question about what GM does in informing the customers about the details. Why give them a pass?

I'm OK with GM managing my battery for longevity in the 3 Volts my family has. Same as I'm OK with Tesla managing my battery for longevity.

Again, did GM document to you how they are managing your Bolt's kW power flow over a single charge? Do they start at 44kW and keep that rate until you stop the charge? Or does the BMS manage that rate? Is it documented? Will it change over the life of your battery? Is it documented?

Again, did GM Bolt document to you how they are managing your Bolt's kW power flow over X number of DC charges or Y months? Do you think it will remain the same from day 1 to year 10? Is it documented?
GM hasn't (in the...7 vehicles I've possessed over the years) applied an update without my knowledge that degraded the performance of my vehicle like Tesla has done once already (ludicrous launch limiter), and likely again with the fast charging hard cap limit.

GM states that I can charge up to 25 miles an hour @ 240V/32 amp EVSE, and up to 90 miles in 30 minutes when hooked up to a 80 kW fast charging station. I've realized the 25 miles/hour figure, but I have yet to realize 90 EPA miles in 30 minutes, but then again I have only used a 50 kW max DCFC station, not 80. I'm not even sure why you are even bringing up the Bolt, because we are talking about Tesla's (loose) business practices here.

Looking at the thread on TMC again, I see more people have come forward stating they have been "SC neutered" as well. Tesla better state some official soon before the crap hits the fan.
Don't buy a Tesla. problem solved.
A better thing would be don't post in Tesla forums.

Then again if you are worried about charge rate and even with the "supposed" reduction isn't it still faster than the Bolt? Meaning that if the Tesla is to slow to charge wouldn't that mean the Bolt is so slow it shouldn't even be considered?
If you bothered to read either of the threads on either forum, the main issue is Tesla sneaking in ninja firmware updates that degrade performance without informing owners of such changes. Just like the Ludicrous mode counter debacle. Duh.

Bolt's DCFC rate may be relatively slow, but at least GM is upfront about it. The max fast charging rate is likely higher than published specs.
"up to 90 miles in 30 minutes when hooked to a 80 kW DCFC" is what is in the manual. I don't think anyone ever said "it will fast charge exactly like a Spark EV!".

Anyways, looking at the Spark EV owner forums, some.owners are experiencing notable degradation...I bet fast charging is one of the reasons.
So it's confirmed that Tesla does permanently reduce SC rates after so many DCFC sessions. JonMc also did not dispel the DCFC hard counter belief, nor to he address if CHAdeMO charge sessions (can be as low as 18 kW) have an impact on the eventual SC max rate neutering.
He said nothing that confirmed a charge session counter, either. He did indicate that the BMS changed the charge parameters based on age and usage, but provided no indication of how Tesla determines that age/usage that I saw.

I'm not sure how that leads to "after so many DCFC sessions."
And that is what many Tesla owners want to know; unfortunately, JonMc did not address all the questions people want answered.

-How many DCFC sessions before this max SC charge rate neutering takes place?
- Does CHAdeMO charging have an effect on how fast the reduction happens? If so, do 18 and 50 kW charge rates have the same impact?
- Is rarely ever charging AC a factor?
- Is the limitation based on time DCFC'ing? Or sessions? kWh charged? Miles driven? All of the above?

Tesla's continued lack of clarity on the issue is still a huge point of contention of owners. I don't think the thread on TMC would have 800+ replies if it wasn't. ;)
Tesla's tweaked chemistry introduced in 2015 in the 90 kWh packs that included more silicon may be the reason for the decreased SC capability:

Usage of silicon allowed for increased energy density in cells, but with the downside of decreased longevity, which may be finally surfacing now with frequent DCFC'ing owners.

"Silicon’s challenges, however, arise from the same attributes that make it attractive. Unlike the porous graphite material that has specific sites open and waiting for ions, when the lithium-silicon alloy forms, the structure of the anode changes, resulting in large volumetric fluctuations. For example, if a particle of silicon absorbs as much lithium as thermodynamically possible, its volume increases by about 300%. That compares to about 7% expansion observed in the intercalation of lithium into graphite.

The problem with the current state of silicon anodes is that the repeated expansion and contraction during charging and discharging leads to drastically reduced cycle life."

So that explains why owners of older Model S's have not experienced the max SC rate neutering. This may be an issue unique to the 90 kWh packs introduced in 2015.

I bet owners of 2015 90 Teslas wish they knew about this prior to purchasing.
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You bet wrong. My Spark EV lost over 25% of its battery capacity over three years and I didn't even have fast charging.

Also, you have ZERO proof that Tesla "sneaked in" a software update to throttle back charging rates. But let's say for kicks they did do that. Good for them, they apparently understand battery life/conditioning better than GM does if they adjusted battery charging capacities in order to increase battery life and longevity.

Anyway, we'll wait for your proof. As of yet, there's been none and any owner issues and/complaints have been individual issues/examples that have ZERO bearing on the fleet. And, as mentioned earlier, these seem to be issues that have reached back as far as mid-2016.
Too bad your Spark EV did not have DCFC. Would have been a good data point for how GM BEVs handle peak DCFC charging in degraded states.
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