Some California Superchargers not providing maximum charging rates

[MITE46]

This problem seems harder and harder to track. Recently I noticed that when arriving with a low SoC <10 miles the ramp up is really slow, increasing by 1kw every few seconds. It's almost better to arrive with >10 miles or reset the charge session after >10 miles.

Definitely think it is heat related as throttling happens quite quickly(<5 min) when ambient temp is hot...and relatively slower (15 min) when it is cool outside. Not totally convinced it is the cabinet because switching between 1A and 1B yields fast charging speeds again.

My new strategy is arrive with 10mls<SoC<20mls. Charge at 110kw until throttled(usually +35mls), move car to another stall, charge at 110kw (usually another +35mls), and move one last time for the last 30mls to get to next SC. This saves me at least 20 minutes...Some other owners thought I was crazy, but it also worked for them, so they started doing it...LOL

But I agree with everyone, Tesla's silence about this issue just makes it worse.

 

[cpa]

Here are my actual data from Supercharging in Fresno on Saturday, December 3 at 3:00 PM:

I was returning home from a week in the desert, and I wanted to see how long it would take to charge from 12% to 50%.

Ambient air temperature was 60 degrees. Minimal breeze.
Battery level was 12%
Initial charge rate: 116kWh

The charge rate stayed steady at 116kWh until the battery percentage climbed to 18%, a matter of about 3 minutes. The rate then started to drop quickly over the next 2-3 minutes to 52kWh. It stayed there and slowly ramped up to 58.

I immediately went to the plug, and it was quite hot. Not as hot as the door handles in July, but hot enough not to be able to hold it for a long time. After 5-10 seconds it was quite uncomfortable. I unplugged and hung up the cable and waited about 30 seconds. I then plugged back in and noticed that the charge rate had climbed to around 68 kWh and stayed there before starting to taper at around 35% battery level.

I do not recall the charge rate at 51% exactly, but I think it was around 50kWh.

I unplugged at 51%. The total time, including my brief interruption, took nearly 30 minutes to go from 12% to 51%.

This is only one set of data. But it seems like the handle gets very hot very quickly, and the car's safety mechanisms kick in to reduce the charging rate.

 

[whttiger25]

Here are my actual data from Supercharging in Fresno on Saturday, December 3 at 3:00 PM:

I was returning home from a week in the desert, and I wanted to see how long it would take to charge from 12% to 50%.

Ambient air temperature was 60 degrees. Minimal breeze.
Battery level was 12%
Initial charge rate: 116kWh

The charge rate stayed steady at 116kWh until the battery percentage climbed to 18%, a matter of about 3 minutes. The rate then started to drop quickly over the next 2-3 minutes to 52kWh. It stayed there and slowly ramped up to 58.

I immediately went to the plug, and it was quite hot. Not as hot as the door handles in July, but hot enough not to be able to hold it for a long time. After 5-10 seconds it was quite uncomfortable. I unplugged and hung up the cable and waited about 30 seconds. I then plugged back in and noticed that the charge rate had climbed to around 68 kWh and stayed there before starting to taper at around 35% battery level.

I do not recall the charge rate at 51% exactly, but I think it was around 50kWh.

I unplugged at 51%. The total time, including my brief interruption, took nearly 30 minutes to go from 12% to 51%.

This is only one set of data. But it seems like the handle gets very hot very quickly, and the car's safety mechanisms kick in to reduce the charging rate.

That's pretty bad. I'm usually very frustrated when I get throttled to 68kw. Regardless of your battery size, at a 50% SOC 50kw is way too low.

 

[BriansBucketList]

I'm at the Fremont charger, and there were about 5 stalls available. First 4 were B stalls with A in use. About 30kW. The last B stall without an a stall in use was 60 kW. It's cloudy today, but last time I was here, more stalls were at 60kW

 

[bxr140]

Regardless of your battery size, at a 50% SOC 50kw is way too low.

Not true. That's about in the middle of the range for older 60s.

 

[gaswalla]

Report of reduced charging at the brand new (not even on official Tesla website) Santa Ana superchargers. That eliminates any possibility of wear and tear or load issues.

 

[ssrajputev]

I was at Fremont yesterday morning (around 9:30 am). I arrived with about 15% charge remaining (60 with software-limited 75 battery). I had to share with someone else in the beginning. My car was only charging at 30 kw in the beginning.

I was there for a factory tour, so I had to leave my key with the front sales specialist. When I came back from my tour, my Tesla app said my car was done charging at 10:19 am. That is pretty slow, considering I was only charging from 15-80% on a 75 battery. I don't know if there was another sharing with me the entire time, while I was at the tour.

This was my fourth or fifth time charging my car at Fremont since getting it in August. Each time, I have yet to get the advertised maximum rate. This is regardless of if I was not sharing or not, going at night or early in the morning (cables would be hot or not). The fastest rate I have ever gotten is 75 kw (6:30 am with no one sharing).

 

[apacheguy]

Several experiences supercharging over the past weekend indicate that the cable temperature (as measured near the handle of the connector) is the biggest factor in limiting the power delivered. Overall, supercharging worked much better than it did over the summer. A lot of this had to do with ambient temperature being lower than 50 F.

I have data from CAN that I hope to have worked up and will post it here to share.

 

[apacheguy]

The limiting/throttling/USPR is absolutely not related to pack temperature. As you can see, my battery temp was consistently increasing throughout the charge session, yet I was able to restore normal charging amperage by cooling the connector and cable. Also, note that no other Tesla connected to any stall at the site for the duration of the data collection.

Additionally, I noticed that in lieu of cooling the cable you can simply switch stalls from A to B (on the same cabinet) and this will restore a normal charge rate. So, it has nothing to do with the car, it has nothing to do with the cabinet overheating, and it has everything to do with the temperature of the cable/connector from the pedestal.

Bottom line: Yeah, this sucks. I mean, SpC used to be a set and forget experience. Plug the cable into an unpaired stall and walk away. Now, it appears that Tesla Engineering has tightened the thermal limits and aggressively tapers the charge rate if they see the connector getting too warm. While I appreciate the reasons for this, it significantly degrades the user experience and I urge Tesla to come up with another solution. (What happened to liquid cooled cables???)

Unfortunately, the workaround for this means that you must stay with your car the entire time and be ready to act in case the rate begins to decline at a rapid rate. I witnessed this behavior ~50% of the time. Sometimes supercharging works great, but in others not so well.

I had this happen at the BRAND NEW supercharger at Anderson's Split Pea. So even new equipment is no guarantee that this will not occur.

 

[Missile Toad]

...yet I was able to restore normal charging amperage by cooling the connector and cable. r.

How did you do the cooling? If it was me, I'd use a can of compressed air, or one of those blue 'ice' packs.

 

[apacheguy]

Yeah I thought about the ice pack idea but I needed some way to keep it cool for several hours. I'll probably pack an ice chest next time. I ended up using a water soaked rag towel.

 

[FlatSix911]

Well done ... confirms one theory on SC throttling

The limiting/throttling/USPR is absolutely not related to pack temperature. As you can see, my battery temp was consistently increasing throughout the charge session, yet I was able to restore normal charging amperage by cooling the connector and cable. Also, note that no other Tesla connected to any stall at the site for the duration of the data collection.

Additionally, I noticed that in lieu of cooling the cable you can simply switch stalls from A to B (on the same cabinet) and this will restore a normal charge rate. So, it has nothing to do with the car, it has nothing to do with the cabinet overheating, and it has everything to do with the temperature of the cable/connector from the pedestal.

View attachment 206716

Bottom line: Yeah, this sucks. I mean, SpC used to be a set and forget experience. Plug the cable into an unpaired stall and walk away. Now, it appears that Tesla Engineering has tightened the thermal limits and aggressively tapers the charge rate if they see the connector getting too warm. While I appreciate the reasons for this, it significantly degrades the user experience and I urge Tesla to come up with another solution. (What happened to liquid cooled cables???)

Unfortunately, the workaround for this means that you must stay with your car the entire time and be ready to act in case the rate begins to decline at a rapid rate. I witnessed this behavior ~50% of the time. Sometimes supercharging works great, but in others not so well.

I had this happen at the BRAND NEW supercharger at Anderson's Split Pea. So even new equipment is no guarantee that this will not occur.

 

[NOLA_Mike]

Additionally, I noticed that in lieu of cooling the cable you can simply switch stalls from A to B (on the same cabinet) and this will restore a normal charge rate. So, it has nothing to do with the car, it has nothing to do with the cabinet overheating, and it has everything to do with the temperature of the cable/connector from the pedestal.

Awesome report - thanks for that.

Mike

 

[Missile Toad]

Following the apacheguy graph, above, I'm guessing the the 'fade' or 'limiting' would have progressed much further, but for his intervention. So what could have been a 30% fade in current turned into a 15-18% fade. Apacheguy, do you have any idea how long that fade occurred in your graph? Between it dropping, you cooling, then disconnecting and reconnecting?

You know, if my wife sees me putting ice-packs on a cable... ice packs I had to keep in a cooler specially for this little trick, she is going to just laugh at me.

 

[apacheguy]

@Missile Toad - the data points are spaced roughly 15 s apart. I actually left the car once (and couldn't intervene) and I saw in the logs that it went down below 100 amps over just a few minutes. It recovered somewhat, but stayed pretty low until I moved to the adjacent stall. I have the data from that session if anyone is interested.

 

[bmah]

You know, if my wife sees me putting ice-packs on a cable... ice packs I had to keep in a cooler specially for this little trick, she is going to just laugh at me.

In the first aid kit I keep in my car are some one time use, quick freeze packs (good for sprains). I wonder how well these would work.

Part of me wonders also if cooling the handle is curing the symptom than the disease, so to speak. (What I mean is does this just hide some harmful or dangerous condition that's detected by the handle temperature, but the handle temperature isn't the real problem.)

Bruce.

 

[Missile Toad]

@bmah I just talked to the Tesla Roadside Support. They told me that excessive cooling of the handle actually subverts the normal feedback process. Their calculations indicate that the SuperCharger will engage in a runaway reaction that will lead to unsustainable outputs of about 1.21 Gigagwatts of current being added to the car. As you can imagine, this kind of current actually welds the handle to the charge port, making it impossible to remove the cable. They warned about partial liquefaction of the cable and/or nearby transformer. Some vague references were made to the elephant's foot, AKA corium .

 

[RubberToe]

@bmah 1.21 Gigagwatts of current being added to the car. As you can imagine, this kind of current actually welds the handle to the charge port...

If that happens, is there an exception for the $0.40 per minute Supercharger blocking fee?

RT

 

[whttiger25]

@bmah I just talked to the Tesla Roadside Support. They told me that excessive cooling of the handle actually subverts the normal feedback process. Their calculations indicate that the SuperCharger will engage in a runaway reaction that will lead to unsustainable outputs of about 1.21 Gigagwatts of current being added to the car. As you can imagine, this kind of current actually welds the handle to the charge port, making it impossible to remove the cable. They warned about partial liquefaction of the cable and/or nearby transformer. Some vague references were made to the elephant's foot, AKA corium .

As long as you aren't driving 88mph you'll be fine

 

[rypalmer]

Just to add a data point or two... I traveled from Toronto to Atlantic Canada over the weekend and visited some SC's that I had previously had difficulty at. In total I visited 5 SCs: Port Hope, Kingston, Cornwall, Magog, and Brewer. I had strong charging at all, except Magog, where I arrived pretty dead (<4%) and cold. After a few false starts, it eventually charged well, but it did involve switching charger stacks once.

Port Hope seemed to have newer pedestals, and cables, since I was there last in October. Great performance there too. I believe they replaced underground cables as well, so the fix was fairly involved.

Great trip, and no reductions in max charging rates anywhere that I couldn't definitely say were attributable to the condition of the battery. In fact, I hit 95kW for the first time that I'm aware of. There may have been some HVAC load factored in there, though.

Bottom line: I love this car as much or more in the winter.