If you fast charge, Tesla will permanently throttle charging

[NerdUno]

Other than offending the Tesla worshippers, what was it about the Forbes article that was inaccurate?

 

[scottf200]

Other than offending the Tesla worshippers, what was it about the Forbes article that was inaccurate?

Very misleading to the average user. 5-7 minutes every few hours of supercharging is "slow charge hell". If they would have stated what I did all the readers would be like ... that's not even enough of a problem to waste ink on.

Tesla appears to put overenthusiastic Supercharger users into slow charge hell “permanently.”

 

[TexasEV]

Just my .02 here; in 8 months of ownership of a 60s and trips from San Diego to Santa Fe and San Diego to Atlanta and back, along with a few uses of the San Diego supercharger, I have never seen (what I consider to be) the mythical 3 digit rate of supercharging. To Atlanta and back, stopping so supercharge 30-40 times, I have seen charging consistently starting at 90-95kW and tapering from there. The San Diego SC rates are all over the map, high 30s to low 80s.

That's the starting rate for 60s. It's only the bigger batteries that get 110-115kW, and then it's only if they're nearly empty.

 

[Az_Rael]

And since I charge to 100% daily (which is between 231-238),

Wow, my 2013 P85 "B" pack has a 232 range for my 90% at 50k miles; you certainly have lost quite a bit of range on your battery. Have you ever had Tesla check it for a bad module?

 

[Electricfan]

Why don't you use AC? Exclusively DC? No plug where you live?

Why do you ask? Tesla has never said DC charging hurts the car, or should be limited in any way, have they?

 

[DOCAL]

Reasoning???

A 60/75 kWh pack has less modules in it, so less cells to receive power in parallel, therefore it can't take as much power overall.

 

[NoMoGas]

Oh and BTW there is no "reserve". My car did shut down right when I hit 0 miles so it does seem that the range displayed is accurate and there isn't any phantom "10 miles buffer" that some people claim or falsely believe.

Not a "false belief", I've personally traveled 12 miles beyond "0" on several occasions. That said, it isn't recommended to take one persons experiences and assume that will apply to all others. Lots of variables to each event.

 

[cdub]

Why do you ask? Tesla has never said DC charging hurts the car, or should be limited in any way, have they?

I remember Nissan said that with my Leaf. They even said charging via the 110 all the time wasn't good too. But who knows.

 

[NoMoGas]

Why do you ask? Tesla has never said DC charging hurts the car, or should be limited in any way, have they?

Theyve said max charging can shorten battery life. From the battery's perspective it's ALWAYS DC regardless ofhow the power starts. One way just bypasses the ac/dc converter.

 

[yobigd20]

Wow, my 2013 P85 "B" pack has a 232 range for my 90% at 50k miles; you certainly have lost quite a bit of range on your battery. Have you ever had Tesla check it for a bad module?

My 90% is 216-218. No I haven't had Tesla check for any bad modules. I have had the "needs service performances degraded" limp mode error pop up a few times over the last year though but it's go away and doesn't come back. I'm actually scheduled for service next week to get my front upper control arms replaced and yearly service and was going to ask them to look to see if there is any battery problems due to my seemingly only 60kW usable capacity and those errors.

 

[ohmman]

How does 5 minutes more per supercharging session add up to 30 minutes more on a short trip? I wouldn't call a trip needing 6 supercharger stops a short trip. that's more than 700 miles of driving. Is 30 minutes difference really noticeable on a trip of more than 700 miles, when you're probably eating lunch or dinner at some of those stops anyway?

The 5 minute number also assumes an unpaired stall is available, that the SOC is very low, and that the owner is charging to 90%. The first item can be hit or miss. The second item is a reasonable expectation for most stops. The last item is likely not the case.

I think the reasonable theoretical number for SC hopping with a 90D in relatively dense locations is closer to 3 minutes - assuming charging from a 15% SOC to a 65% SOC. However, I recognize that Supercharger density varies greatly depending on location, and that driver style also varies. A funny thing about doing this math, though, is that one is unlikely to underperform relative to theory. Underperforming means the Supercharger is, for some reason, not supplying the appropriate charge. That issue actually works in favor of the owner, because it means their cap is no longer artificial. Instead, it creates parity and removes the theoretical penalty. The only way that the capped owner would be harmed is if the Supercharger was outperforming for other vehicles - for some reason no longer tapering, or providing 150kW, etc. Or, of course, something else I'm missing.

 

[Electricfan]

Theyve said max charging can shorten battery life. From the battery's perspective it's ALWAYS DC regardless ofhow the power starts. One way just bypasses the ac/dc converter.

Yes, absolutely. I don't charge to 100% because Tesla is honest about that, as you say. But never have they said repeated use of fast-charging DC chargers hurts the batteries. If the OP is getting real info (I hope to goodness he's getting a tall tale from somebody in Tesla service to cover a defective battery they don't want to fix, and that's my strong suspicion), then we've all got to look at how we care for our cars differently.

This post is why I read this forum - its info you'll never get in your inbox from Tesla - again IF this turns out to be true.

 

[Naonak]

The 5 minute number also assumes an unpaired stall is available, that the SOC is very low, and that the owner is charging to 90%. The first item can be hit or miss. The second item is a reasonable expectation for most stops. The last item is likely not the case.

I think the reasonable theoretical number for SC hopping with a 90D in relatively dense locations is closer to 3 minutes - assuming charging from a 15% SOC to a 65% SOC. However, I recognize that Supercharger density varies greatly depending on location, and that driver style also varies. A funny thing about doing this math, though, is that one is unlikely to underperform relative to theory. Underperforming means the Supercharger is, for some reason, not supplying the appropriate charge. That issue actually works in favor of the owner, because it means their cap is no longer artificial. Instead, it creates parity and removes the theoretical penalty. The only way that the capped owner would be harmed is if the Supercharger was outperforming for other vehicles - for some reason no longer tapering, or providing 150kW, etc. Or, of course, something else I'm missing.

Where I'm at (Kansas) and where I travel to (DEN - STL mostly), the Superchargers are always completely empty. It's a very rare occasion I see another Tesla at the Superchargers and if I do, it's only 1. I think I've seen 2 once, with the exception of one of the Denver stations, there were several there. Otherwise, nada... so it's never a case of having an unpaired stall unavailable. My SOC is pretty much always low when I pull in and as you say, it's hit or miss when it comes to charging to 90%. The mid-America SCs are weird... they are spread out at unusual intervals, and none are close enough to skip, but not far enough to make it economical time wise to drive slower ... efficiency wise, it's best to drive as fast as you can between stations.

I was comparing my logs from Apr 2016 vs Apr 2017 @ the Columbia, MO SC. ETA on charge to continue was 20m in 2016, it was 30m in 2017. On both occasions, that estimate was pretty close to when I unplugged and continued on.

2016 SoC Arrival 27%, 62% Departure. Total charge time 21m (+35% SoC)
2017 Soc Arrival 23%, 63% Departure. Total charge time 28m (+40% SoC)

5m, starting at 27% spent > 90kW charging in 2016. 0m > 90 kW in 2017.

I can't compare St. Charles, because that SC was on the blink, sadly.

I'm looking into if I can get the right dates for KC - DEN charges.

 

[ohmman]

2016 SoC Arrival 27%, 62% Departure. Total charge time 21m (+35% SoC)
2017 Soc Arrival 23%, 63% Departure. Total charge time 28m (+40% SoC)

Translating that, and this would assume no tapering (so being conservative in your favor):

21 min / 35% SOC = 0.6 min / SOC % (2016)
28 min / 40% SOC = 0.7 min / SOC % (2017)

Using 2017's rate for 2016's trip:

0.7 min/SOC % * 35% SOC = 24.5 min. So 3.5 minutes more for this particular trip. Any arrival SOC greater than this will have a smaller difference. The more extreme examples should be the ones that you can compare where you arrive with a very low SOC.

 

[Naonak]

Data for KC - DEN:

Hay SC

May 2016:
Charge ETA 30m
SoC 32% Arrival, 75% Departure. 28m charging (+43% SoC) (Drops below 90 kW at the 5m mark)

Nov 2016:
Charge ETA 50m
SoC 29% Arrival, 79% Departure. 37m charging (+50% SoC) (Drops below 90 kW at the 5m mark)


Goodland SC

May 2016:
Charge ETA 25m
SoC 14% Arrival, 69% Departure. 32m charging (+55% SoC) (Drops below 90 kW at the 9m mark)

Nov 2016:
Charge ETA 50m (!)
SoC 2% Arrival, 72% Departure. 44m charging (+70% SoC) (Drops below 90 kW at the 13m mark)


Limon SC
May 2016:
Charge ETA 20m
SoC 7% Arrival, 42% Departure. 17m charging (+35% SoC) (Never dropped below 90 kW charging)

Nov 2016:
Charge ETA 50m
SoC 17% Arrival, 51% Departure. 17m Charging (+34% SoC) (Never dropped below 90 kW charging)

Denver SC
May 2016:
Charge ETA 50m (Destination, charge estimate was for 90% charge)
SoC 28% Arrival, 69% Departure. 22m Charging (+41% SoC) (Drops below 90 kW at the 14m mark)

Nov 2016:
Charge ETA 25M (Passthrough)
SoC 12% Arrival, 63% Departure. 26m Charging (+51% SoC) (Drops below 90 kW on the 22m mark)

 

[Naonak]

I will be interested to see what my trip KC - DEN is next month... it appears to me to be a gradual tapering of my top end charge rate. The charge rates for May are higher when above 90 kW than they are for November (May averaged around 110ish (between 108 and 112 mostly), November around 104ish (Between 100 and 108). Now with an apparent 90ish kW limit or less, this next trip should provide an interesting picture.

That Columbia SC data is just one SC... that is not the entire trip. There's 2 SCs going KC to STL and 3 SCs going STL to KC (St. Charles, Columbia, Independence)

 

[SageBrush]

OP: I cannot reconcile your great concern with a couple minutes lost time at a SC with your choice to sit at ChaDemo chargers rather than charge at home while you sleep.

 

[AnxietyRanger]

I am not saying it is progressive, just that it appears to be so, but with my limited dataset, I can't really make a claim one way or another.

I will say, though, that even at 5m (and that estimate seems to be low from my experience so far) that still adds 30m to an otherwise short trip... To put it another way, it adds up to 5% more time than before. This is on top of the additional charging time penalty that already existed. So a trip that takes 9 hours in an ICE now takes 12.

Good info and fair points, appreciate you sharing.

 

[AnxietyRanger]

I find this thread interesting, because the OP says he only has 30k miles and has encountered this "throttling". I have 148k miles. My daily commute I cannot make it to work and back on a single charge. I range charge to 100% every morning I go to work (I have to, or else I wont have enough left to make it to the supercharger in order to get home), and I supercharge almost every day during the week, sometimes twice a day. Twice a week it can even be 3x daily. I've been doing this for 4 years now. The number of times I supercharge is ridiculous, probably more than anyone else ever has. There's no way the OP has even come close to the number of times that I supercharge. Yet I have experienced no throttling and always observe around 117-118kWh during the beginning of charging. It does take about 30-40 minutes to go from 0-80% and from 80-100% can be another 30-40 minutes. This is normal AFAIK.

I see that you have a P85. So far it seems all reports of throttling are from 90 kWh cars. There is also (see #385) the Tesla tech reference to "H packs" having some DC charging related issue.

There seems to be a couple of reports now from high-mileage 85 kWh owners that has been no throttling there. The 85 vs. 90 kWh could be significant.

 

[AnxietyRanger]

Hey, at least Forbes got there first. Electrek and Teslarati continuing their silence as usual on any thorny Tesla topic?