Some California Superchargers not providing maximum charging rates

[ShotgunF15E]

I'd put my money on this being a bug in how the car communicates with the supercharger. Months (years? ago), around the first time this started happening (ie rumours of throttling, the time of the infamous Supercharger abuse letters), I was charging at Gilroy supercharger and only getting 59-60kW when I should have been getting 120kW. There was a tech working on another charger, and I asked why I was only getting 60kW. He looked at it (I was at about 3% soc, unpaired, temperate weather/battery temp), pressed a few buttons on his laptop and I started getting full charge rate. He said it was configured incorrectly. Wouldn't surprise me if something similar is happening.

But yet it's only certain locations. It'd be nice to build a known list of throttle happy SC locations...

 

[apacheguy]

I'd put my money on this being a bug in how the car communicates with the supercharger. Months (years? ago), around the first time this started happening (ie rumours of throttling, the time of the infamous Supercharger abuse letters), I was charging at Gilroy supercharger and only getting 59-60kW when I should have been getting 120kW. There was a tech working on another charger, and I asked why I was only getting 60kW. He looked at it (I was at about 3% soc, unpaired, temperate weather/battery temp), pressed a few buttons on his laptop and I started getting full charge rate. He said it was configured incorrectly. Wouldn't surprise me if something similar is happening.

Hmm. This has been going on for several weeks. If there was some communication error, I would expect a quick fix to be rolled out OTA. FWIW, I was on 2.28.60 when I experience these issues.

 

[GHammer]

Road tripping through California last week, and had the issue of initially ramping up to 115kW and after a few minutes having it dive to about 50kw. Happened at the brand new Folsom location, Mammoth Lakes, and Mt. Shasta. Unpaired all times and each time I was able to regain full speed by moving to a different number pedestal. Didn't see this in Utah, Nevada, idaho or Oregon. Temperature didn't seem to make a difference as it was in the low 80's in Mammoth. Charged fine at 110 degrees in Nevada.

 

[aesculus]

I don't know what caused this but yesterday I pulled into the Dublin, CA supercharger and waited 10 minutes for a spot. Started to charge at 250 mph which is good (battery at 30%). It said I needed 40 minutes to get to 90%.

I went into use the bathroom and took my fob. On the way back out (5 min later) I heard a car alarm and thought it might be my car. I had locked my wife inside since since I was only going to be gone a few minutes (I know, its not good to leave an unattended spouse in a hot car ...). She forgot the car was locked and opened the door and that set the alarm off. It was only on for 30 seconds or so.

Anyway from that point on I never charged at more than 100 mph. The car in the next stall pulled out and it was replaced and that car left too after about 30 minutes and again my rate never got above 100. Sometimes it went down to 94 mph.

So my question is: Did the car alarm reset my charging? (note there was nothing on the screen about the charging stopping or resetting), was I being throttled, or was something else going on?

 

[Cosmacelf]

Does your spouse know to just touch the touchscreen to turn on the AC?

 

[whttiger25]

I don't know what caused this but yesterday I pulled into the Dublin, CA supercharger and waited 10 minutes for a spot. Started to charge at 250 mph which is good (battery at 30%). It said I needed 40 minutes to get to 90%.

I went into use the bathroom and took my fob. On the way back out (5 min later) I heard a car alarm and thought it might be my car. I had locked my wife inside since since I was only going to be gone a few minutes (I know, its not good to leave an unattended spouse in a hot car ...). She forgot the car was locked and opened the door and that set the alarm off. It was only on for 30 seconds or so.

Anyway from that point on I never charged at more than 100 mph. The car in the next stall pulled out and it was replaced and that car left too after about 30 minutes and again my rate never got above 100. Sometimes it went down to 94 mph.

So my question is: Did the car alarm reset my charging? (note there was nothing on the screen about the charging stopping or resetting), was I being throttled, or was something else going on?

Based on the timing you describe I think the general issue of charging dropping after about 5 minutes that I have experienced as have others is more likely the cause than the car alarm.

 

[ka9q]

If anybody wants to do a scientific study, I suggest checking the wholesale spot electricity rates at times of unexplained charging power decreases. Here's one place with possibly useful data:

California ISO - Price Maps

Somebody else already mentioned demand charges. As you can see, they are substantial. It's how a utility makes its money from commercial customers, and it's not at all clear how to minimize them at a public EV charging site without annoying your drivers.

(Residential customers pay substantial per-kWh markups instead of demand charges, but we're limited to relatively small powers anyway.)

 

[FredTMC]

If anybody wants to do a scientific study, I suggest checking the wholesale spot electricity rates at times of unexplained charging power decreases. Here's one place with possibly useful data:

California ISO - Price Maps

Somebody else already mentioned demand charges. As you can see, they are substantial. It's how a utility makes its money from commercial customers, and it's not at all clear how to minimize them at a public EV charging site without annoying your drivers.

(Residential customers pay substantial per-kWh markups instead of demand charges, but we're limited to relatively small powers anyway.)

When tesla has some extra CapEx lying around that they are using, they'll need to add Solar and PowerWall batteries to many Supercharger locations. This will reduce their utility "demand charges"

 

[aesculus]

Does your spouse know to just touch the touchscreen to turn on the AC?

Probably needs a refresh.

The AC was on but probably not at a level that suited her. I also suspect she wanted to get out and stretch the legs a bit. She was about ready to reach for the Tesla app on her phone to reset the alarm which is pretty tech savey, and then I showed up.

 

[ka9q]

Yes, local solar and storage could potentially reduce demand charges at supercharger sites, but consider how difficult it would be to avoid annoying the drivers. If there's insufficient solar and storage to supply what the chargers are demanding, then either Tesla can cut power to what's available or they can pay the demand charge for the excess -- and this only has to happen once every month.

 

[ka9q]

By that I mean if they let their peak demand go up to satisfy all the charging customers, then doing this just once (in a 15 minute averaging period) will incur that big demand charge, even if they never draw that much power again for the rest of the month. So they have a difficult choice: how much more money are you willing to spend to avoid having to slow charging in a relatively small number of cases?

 

[whttiger25]

When tesla has some extra CapEx lying around that they are using, they'll need to add Solar and PowerWall batteries to many Supercharger locations. This will reduce their utility "demand charges"

Powerwall may help but not in high use locations that are full for long periods of time. And solar won't do a damn thing besides be a nice looking/feeling addition. Assuming the optimal 10 watts per square foot you get with direct sunlight on PV's, to power a 12 station 900 kw supercharger (150kw X 6 pairs), you need 90,000 square feet of photovoltaics, just under 2 football fields.

 

[ecarfan]

I am at the Arastedero Supercharger right now. The charging cables are being replaced with the newer style (no physical button in the handle, just the area where you press). I asked the person replacing the cables if the new cables would allow faster charging or were more reliable, or something else. He said he couldn't answer because his answer would just be a guess. Then he said that there had been reports of problems at this location and the new cables could be a response to those reports. He could not be more specific than that.

It seems possible that the "problems" he referred to were the slow charging rates and the new cables were a solution. That is only speculation on my part, the person I spoke to did not say that specifically.

I also noticed this new style cable at the Gilroy Supercharger yesterday.

Right now my S is charging at a normal rate for a low state of charge, meaning well over 300 mi/hr and over 200A.

 

[GHammer]

I am at the Arastedero Supercharger right now. The charging cables are being replaced with the newer style (no physical button in the handle, just the area where you press). I asked the person replacing the cables if the new cables would allow faster charging or were more reliable, or something else. He said he couldn't answer because his answer would just be a guess. Then he said that there had been reports of problems at this location and the new cables could be a response to those reports. He could not be more specific than that.

It seems possible that the "problems" he referred to were the slow charging rates and the new cables were a solution. That is only speculation on my part, the person I spoke to did not say that specifically.

I also noticed this new style cable at the Gilroy Supercharger yesterday.

Right now my S is charging at a normal rate for a low state of charge, meaning well over 300 mi/hr and over 200A.

I ran into the problem at the brand new Folsom charger with the new cables.

 

[apacheguy]

I'd be surprised if the cables were to blame. About a year ago I SpC in hot weather and experienced none of this throttling nonsense.

 

[joebob73]

I was at the Fountain Valley SC yesterday around 6pm and experienced the same issue. Initially plugged it in and got 102kW. After about 10 minutes, it dropped to 28kW! I did not try to plug/unplug and could not move since other stalls were full.

 

[tbleakne]

I have experienced reduced charging power on unpaired SC several times where I have been able to increase the power 10, 20 or more kW by moving to another stall part of a different pair. The most recent was a few months ago at Buttonwillow where I was the only car.

Neither utility power cutback or strategy to reduce demand charges, which are high, makes sense if only a few cars are present.

I offer this possible explanation: it is possible that the charger unit feeding a particular pair of stalls might have one or more of its 12 10kW single phase charger units inoperative, and it is designed to continue operating at reduced power with that charger(s) offline. It would have notified Tesla, but they could elect to delay fixing it if the location is not currently experiencing queues of cars.

The 10kW 40A charger units are the same as in the Model S (until the recent upgrade to 48A). Last week I had a failure of my master onboard charger. I have dual chargers, and I usually charge overnight at very modest current level, typically only 24 to 32A. I can see the power being split between the two chargers as first one and then the other ramps up at the beginning of the charge. My car was plugged into a Chargepoint L2 drawing 30A for 6 minutes when its charger failed.

I have seen a few scattered reports that charger failure in the cars is not uncommon. One person posted that he had had two failures in 40K miles. Another was upset to learn that at 55k miles his charger replacement was not under warranty.

If my charger treated so lightly experienced a failure (45K miles, 2yrs 9 months), it seems possible the same units in SCs under near constant heavy use might be experiencing frequent failures. Hopefully the new 48A design is more reliable, and eventually the units in the existing SC can gradually be swapped out for the new model, which should offer higher peak power of 48A * 277V phase to neutral * 12 = 160 kW. Presumably the 90kWh battery packs can handle more than 120kW peak, and for the rest of us there will be more power available for the secondary car on a shared charge.

I took my car to Buena Park Service Center last Wednesday. They service cars in the order they arrive, irrespective of appointments, and they had a 30 car backup. They did not get to diagnosis until Saturday, and the App showed that they first tested the new charger last night, Monday.

I am grateful this failure occurred now, because I had forgotten that the 4yr comprehensive warranty is also limited to 50K miles, only 4k miles left of my car. They told me I can extend the warranty for 4 more years for $4K. I am planning to trade in my S85 MS for either a Model 3 (I have very early reservation) or another MS in 2018, so I would only be able to use 1.5 years of the warranty extension.
Q: Since Tesla offers a full warranty on CPO cars, does that mean they would give me no extra credit for trading in a car with several years of warranty extension ?

 

[AMPd]

No more throttling?

I made a trip to the Sierra Nevada mountains and on the way back home I stopped to charge at the Galleria in Roseville, it was just me and another model s there, charged at regular speeds the entire time.
Peaked at 110kw, stayed there for a bit and then started tapering at its normal rate.

Today made the same trip, this time stopping at the Rocklin SC, same thing, got full speed with normal tapering, this time I took the last spot available. Makes me think there was a Service Center model s plugged in that was fully charged.

Happy to see that we might be done with the throttling issue for the year.

 

[bmah]

Today I tried a charge in Fresno on my 85D. Pulled into stall 2A at 1745 with 25% SOC, outside temperature 91F (my wife was looking very strangely at me as I was jotting these statistics down in my notebook, but anyway...). Ramp-up to 100+kW was pretty quick but during the next three minutes dived down to 37kW. Then saw power of 60kW at 1750, up to 68kW at 1751, 60kW at 1752, 57kW at 1754. This seemed wrong.

After this I moved over to stall 3B at 1758 with 42% charge, where my car pulled as much as 106kW, gradually ramping down to 88kW at 1800 (45% SOC), 58kW at 1814 when we left with 64% SOC.

Bruce.

 

[aesculus]

Bruce: The only thing you did not tell us was if you were paired in either stall. Also don't forget pairing may not be linear (ie the adjacent stall).