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

9480 Views 77 Replies 22 Participants Last post by  Steverino, 
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https://teslamotorsclub.com/tmc/posts/2088343/

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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scottf200
saghost said:
So GM told you that it would charge slower than a Spark EV and start throttling around 50% SoC in big steps?

I must have missed that thread. The only thing I remember GM communicating was the 90 miles in 30 minutes, and I remember a whole lot of speculation here about how much faster the car might charge.

Not saying a hidden counter is acceptable if such a thing actually exists, but I don't feel like either company has communicated clearly on the subject
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Source for the underlined text is bro1999's own blog post https://bro05.blogspot.ca/2017/03/fast-charging-experiences-with-bolt.html :

The Bolt tapers the max charge rate fairly early compared to say the Spark EV.
While Spark EV owners reported near 50 kW rates from 0% to almost 80% SOC, I've noticed the Bolt starts tapering rates at
around 50% SOC (ramps down to ~38kW/~100 amps) and
again at 70% (down to ~24 kW/~60 amps) from peak ~46 kW/125 amp charge rates at a 125A station.
At a little over 80%, the rate again tapers down to <20 kW and stays there till fully charged.
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The Tesla owner 90kWh battery cars case in question is currently getting 90 kW charging rate max. In my 90kWh battery car case, I taper down over 10 minutes and stay at 80 kW for 20 minutes see this chart.
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So it looks like any peak charge rate slow down is due to Tesla keeping on top of the cell's physical chemistry. This is the same thing that happens when the cells are cold, or the level is too low. Considering it's a rare thing like Scott pointed out, to have the stars align anyway for a charge session that sees 120kW for only a few minutes, I don't see it as being a big deal when my car gets to that point in its life. Who knows, maybe I'll swap in a 100kW battery or something by the time that happens.

https://electrek.co/2017/05/07/tesla-limits-supercharging-speed-number-charges/
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bro1999 said:
"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.
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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.
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Norton
scottf200 said:
....The Tesla cars 'trip planner' will route you from supercharger to supercharger on such trips. You do not have to fill all the way up as it tells you when you can continue your trip when you have about at 12%-15% extra buffer to make the next one. Lunch, bathroom breaks, etc....
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This is such an awesome feature !
I can see the Bolt getting a free SW update OTA in the future for similar Nav functionality.
In the future where there is a usable highway network of 80 - 120 kW CCS chargers (or whatever is the up limit of the SAE spec).

(Just kidding, even if the built in Nav was user friendly and could handle this updated function, the General is not going to give it away...)
{not a fanboi of Chevy, definitely not a fanboi of a large 5000 lb EV that gets gushed about in reviews, with never a negative comment. wth is an "ultra-efficient electric motor" for instance?...}

bro1999 said:
....Anyways, looking at the Spark EV owner forums, some.owners are experiencing notable degradation...I bet fast charging is one of the reasons.
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Some may post a time or two about perceived 'degradation'. The ones that plot each battery cycle show a WIDE range of results. It seems like monthly averages might be better. The data gathering of the system may not be precise.
It's there, but what is notable. I question how the Volt will not display any degradation.
There was that one technical study with two groups of Leafs, one using only DCFC and the other on L2. The results didn't show a problem with DCFC. Can't find it now...
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The integrated trip planner is something that could easily be done through Google Maps. I'm not really concerned about it, truthfully. I check my fuel level, look at the route I'm going to take, and I drive to my destination. Never really needed my hand to be held.
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scottf200
Ladogaboy said:
The integrated trip planner is something that could easily be done through Google Maps. I'm not really concerned about it, truthfully. I check my fuel level, look at the route I'm going to take, and I drive to my destination. Never really needed my hand to be held.
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But is everyone like you and is that they way to appeal to a large mass of customers? Without the smarts of a 'trip planner' people often think they need to charge up to 99 or 100% when 80 or 85% will leave plenty of buffer and charge to MUCH faster.
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scottf200
Chris TX said:
So it looks like any peak charge rate slow down is due to Tesla keeping on top of the cell's physical chemistry. This is the same thing that happens when the cells are cold, or the level is too low. Considering it's a rare thing like Scott pointed out, to have the stars align anyway for a charge session that sees 120kW for only a few minutes, I don't see it as being a big deal when my car gets to that point in its life. Who knows, maybe I'll swap in a 100kW battery or something by the time that happens.

https://electrek.co/2017/05/07/tesla-limits-supercharging-speed-number-charges/
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As people thought: "...after a very large number of high-rate charging sessions. This is due to physical and chemical changes inside of the cells. ... may increase total Supercharge time by about 5 minutes" ... 5 minutes ... ho-hum. Maybe something else will pop up in the next couple days beside the below but so far fairly benign especially if they sustain a reasonable kW rate now (which is obviously less than the max as in my charts example).

In a statement, Tesla explains that it is a software limitation to optimize for the best possible owner experience that’s within the limits of physics. Here’s the [Tesla] statement in full:

“The peak charging rate possible in a li-ion cell will slightly decline after a very large number of high-rate charging sessions. This is due to physical and chemical changes inside of the cells. Our fast-charge control technology is designed to keep the battery safe and to preserve the maximum amount of cell capacity (range capability) in all conditions. To maintain safety and retain maximum range, we need to slow down the charge rate when the cells are too cold, when the state of charge is nearly full, and also when the conditions of the cell change gradually with age and usage.

This change due to age and usage may increase total Supercharge time by about 5 minutes and less than 1% of our customers experience this.

Tesla is not slowing down charge rates to discourage frequent Supercharging – quite the opposite. We encourage our customers to use the Supercharger network at their discretion and we committed to doubling the number of worldwide chargers just this year. We also want to ensure that our customers have the best experience at those Superchargers and preserve as much vehicle range as possible – even after frequent usage.”
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[update]
Above text is from the article but JonMc (Tesla) posted it on the TMC forum as well. https://teslamotorsclub.com/tmc/posts/2092107/
JonMc is Tesla’s president of Global Sales and Service, Jon McNeil.
[/update]
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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.
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scottf200
bro1999 said:
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.
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Jon McNeil -- Tesla’s president of Global Sales and Service:
... To maintain safety and retain maximum range, we need to slow down the charge rate when the cells are too cold, when the state of charge is nearly full, and also when the conditions of the cell change gradually with age and usage.

This change due to age and usage may increase total Supercharge time by about 5 minutes and less than 1% of our customers experience this. ...
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5 minutes -- ho-hum

Compare the charging time (with slow down even) of a Tesla Model 60 to a Bolt 60. How much longer is the Bolt to charge with it's rapid neutered slowdown? Starting at 25% or 50%(!).

Reminder: bro1999's own blog post https://bro05.blogspot.ca/2017/03/fast-charging-experiences-with-bolt.html :

The Bolt tapers the max charge rate fairly early compared to say the Spark EV.
While Spark EV owners reported near 50 kW rates from 0% to almost 80% SOC, I've noticed the Bolt starts tapering rates at
around 50% SOC (ramps down to ~38kW/~100 amps) and
again at 70% (down to ~24 kW/~60 amps) from peak ~46 kW/125 amp charge rates at a 125A station.
At a little over 80%, the rate again tapers down to <20 kW and stays there till fully charged.
Click to expand...
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bro1999 said:
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.
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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."
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saghost said:
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."
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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. ;)
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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: https://chargedevs.com/features/tes...y-a-closer-look-at-silicon-anode-development/

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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bro1999 said:
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. ;)
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I agree it'd be good to know specifics, but limiting SC to "only" 90kW is hardly neutering. It's still almost twice as much power as the average chademo or CCS station around today. If the "only affects 1% of customers" claim is true, I can see why they haven't talked more about a fringe scenario.
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bro1999 said:
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. ;)
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Hilarious that actual Tesla owners are telling you that this is not a big deal, but you, as a non-Tesla owner are making it out to be this scandalous thing.

Don't you have some actual rage to vent about your own car, since the manufacturer has been tight lipped about everything, regarding its substandard, slowest-on-the-market DCFC capabilities?

Thanks for your concern.
-An actual Tesla owner
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scottf200
bro1999 said:
As a person that at one time considered a Tesla purchase, I now feel justified in spurning "big T" for the Bolt. ;)

What is hilarious is that more and more Tesla owners are making posts lamenting Tesla's lack of transparency. But I guess people like you that have the Tesla-shaded blinders on, transparency is not a concern. Good for Tesla to have such customers that don't ever complain about anything and just keep on chugging the Tesla red kool aid. ;)
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What I find hilarious is we are talking about 5 minutes.

How many minutes did charging or dealing with charging take you here? : https://bro05.blogspot.com/2017/04/attention-to-detail.html

Everything is relative and the Tesla pros and ongoing improvements to the car (OTA) as well as the SuperCharger network (doubling this year) outweigh the cons ... by far. The people with issues are using DCFC to the max. Even buying the car and using the maximum range and not accounting for known degradation due to physics and chemistry.

It is not like GM is documenting or telling Bolt owners about degradation over time and how their BMS algorithms will slow down the charging ... but certainly they had to account for that ... because their batteries are not magical defying physics and chemistry. Try doing CCS DCFC almost everyday and let us know how your battery holds up.
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jupitermoon said:
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.
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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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Mcgsp
Wow 10 pages of what basically boils down to a car manufacturer with new technology self correcting itself before something goes horribly wrong. How dare they, aren't they supposed hide these issues and hope no one notices. The Horrors!

How many car manufacturers or their sub contractors hid important information to deadly consequences, when they could of easily shared the information both with the press and their customers. How many years did GM know about the ignition switch in their chevrolet and pontiacs before the recall? Just one of many issues out hundreds of hidden flaws in cars that was hid from the light of day.

I'm not saying Tesla is perfect but their business model is a bit refreshing in how they deal with discovered issues. Again we are talking about relative new battery technology that have been in cars for just 5 years. EV technology is still on a learning & manufacturing curve and while we except perfection for our cars, but after over 120 years of automobiles being on the roads, we still find car manufacturers producing ICE automobiles with defects. So cut Tesla some slack.

Its great that the Bolt and the Volt were conservative in their numbers for their battery packs and kudos for chevrolet in dealing with the over blown Gen 1 battery fire. But if we are talking about time and money, Tesla with their over the air updates vs taking time and energy to drive to a chevy dealership for our updates and then either wait for them or comeback to retrieve the car how is this not inconvenient. And the fact that Tesla will do these things without being prompted or forced to either by law suits or NHTSA is a welcome change. So in the overall aggregate is Tesla so wrong.
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Steverino
The back and forth on this thread is dubious at best. It boils down to 10 page of "tesla lied" refuted with "you are wrong". It's really a pointless exercise to continue as everyone who cares has stated their position at least 6 times. Thread closed.
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