Some California Superchargers not providing maximum charging rates

[Cosmacelf]

I wonder if the slow charging issues has to do with the cars, and not the SCs. If you had been driving 85 mph and just got to a SC, maybe your battery is hot and can't handle fast charge rates?

 

[David99]

I've charged over 300 times at Superchargers and visited aprox 60 different stations across the country. Extreme heat can cause reduced charge rate. It's less the Supercharger itself, it's the car/battery that can't be cooled down quickly. The battery has a lot of thermal mass.
In my experience there are very few situations where Supercharging is reduced significantly due to heat.

 

[DDotJ]

I'm sitting at Fountain Valley right now plugging in from 15%. Started off full speed but backed down to 65 kW after about a minute. Switched stalls and same thing happened.

 

[David99]

Tesla is definitely not throttling Superchargers as it would make the problem even worse. It would just totally backfire. I think it's software that is a little too sensitive and too careful sometimes about reducing the charge rate due to different conditions.

Even in brutal heat and long trips, I always got full charge speed at Superchargers. As the car gets older I see more and more reduced speeds when Supercharging. Overall the rate I get now after 2.5 years and 85k miles is about 5 kW less than when it was almost new.

 

[cpa]

Here is my stupid, non-scientific explanation that comes directly via my accounting department:

I wonder if demand charges that Tesla has to pay enter into the equation. Perhaps Tesla wants to limit the demand charges paid to the utilities. We do not know how the demand charges are factored into Tesla's billing from the utilities. With the increase of SC sites in California and the explosion of vehicles using these sites, Tesla may have added some sort of software restriction to the SC.

It is my understanding that demand charges are determined by the highest draw during any 10 or 15-minute period per billing cycle.

So, someone plugs in and receives a decent current. The clock on the software determines that after 6 minutes a new 15-minute window starts, so throttles the charge downward. Driver unplugs 8 minutes later, moves, plugs in again and receives another decent charging rate for 5 minutes when yet another 15-minute window starts, so the software reduces the charge.

I seem to recall that the demand charge per kW are somewhere around $20-$25. The maximum draw per paired stall would be around 125kW. An eight-stall SC in theory could deliver 500kW+ with all stalls occupied. So, I posit that Tesla has software perhaps to limit total SC draw to a lower amount, say 300kW. The software was written poorly in that the throttling is blind to other usage at the various locations--it just limits the current once the demand window reopens.

For illustration only, 30SCs in California times 200kW software induced throttling = 6,000 kW times $20 = $120,000. While that figure is peanuts to Tesla in the greater scheme of things, three months of this savings will likely allow Tesla to install at least another Supercharger location.

I know, this is crazy. But I do think that it is at least plausible. And we do know that Tesla is hush-hush about these sorts of things....

 

[David99]

That would maybe explain limited charging current when all stalls are full. Throttling down when only a few cars are there doesn't get near the peak. The demand charge is once per billing cycle. So once they did peak out and get the higher charge, it's fine to go to the same level the entire month after that. I doubt Tesla building 12 stall Superchargers and then make them all slow all the time to save a little money.

 

[ThosEM]

We all seem to be speculating wildly here, but there is another thread with mostly east coast experiences (search hot weather slow supercharging). We really need Tesla to be more communicative about this issue. Calling them doesn't help much, and I'm not convinced the phone support people really know what is going on. It's pretty obvious that hot weather in peak travel periods is putting stress on the SC system, the net result of which is to degrade the experience.

Of course individual disappointments are not so big a cause of concern, but the worry is that this is a systematic problem with the entire concept of highway supercharging. We'd like to think all those cars out there on a summer weekend should be BEVS, but it seems in practice that a pretty tiny fraction of them are already putting a strain on something that could be revealing a flaw in this entire plan. Tesla shoud address this, if only for the health of their stock price and ability to raise cash...

 

[ShotgunF15E]

Tesla is definitely not throttling Superchargers as it would make the problem even worse. It would just totally backfire. I think it's software that is a little too sensitive and too careful sometimes about reducing the charge rate due to different conditions.

Even in brutal heat and long trips, I always got full charge speed at Superchargers. As the car gets older I see more and more reduced speeds when Supercharging. Overall the rate I get now after 2.5 years and 85k miles is about 5 kW less than when it was almost new.

Either:

A) Tesla is intentionally throttling back their SCs to save on their electric bill

OR

B) Their SC hardware is severely flawed and already experiencing significant sustainability problems which could sink their entire Super Charger strategic plan.

 

[ShotgunF15E]

We all seem to be speculating wildly here, but there is another thread with mostly east coast experiences (search hot weather slow supercharging). We really need Tesla to be more communicative about this issue. Calling them doesn't help much, and I'm not convinced the phone support people really know what is going on. It's pretty obvious that hot weather in peak travel periods is putting stress on the SC system, the net result of which is to degrade the experience.

Of course individual disappointments are not so big a cause of concern, but the worry is that this is a systematic problem with the entire concept of highway supercharging. We'd like to think all those cars out there on a summer weekend should be BEVS, but it seems in practice that a pretty tiny fraction of them are already putting a strain on something that could be revealing a flaw in this entire plan. Tesla shoud address this, if only for the health of their stock price and ability to raise cash...

I've seen enough reduced charging rates at DIFFERENT superchargers here in SoCal to know that the behavior of the hardware has NOTHING to do with outside air temp. I've been in the brutal heat of the SoCal desert where it's 110 degrees outside and I've been driving 90mph across the flats; pull straight in to a SC and it'll charge at full rate from 10% to 90% like a boss....and then I've pull into others in the middle of the night when my car is nowhere near hot or even warm yet and a loan SC at 70degrees outside won't put out more than 60kw. This problem has nothing to do with the temperature outside or even how busy a site is. It can be the middle of the night and you're the only one there and they'll still throttle back.

 

[cpa]

I've seen enough reduced charging rates at DIFFERENT superchargers here in SoCal to know that the behavior of the hardware has NOTHING to do with outside air temp. I've been in the brutal heat of the SoCal desert where it's 110 degrees outside and I've been driving 90mph across the flats; pull straight in to a SC and it'll charge at full rate from 10% to 90% like a boss....and then I've pull into others in the middle of the night when my car is nowhere near hot or even warm yet and a loan SC at 70degrees outside won't put out more than 60kw. This problem has nothing to do with the temperature outside or even how busy a site is. It can be the middle of the night and you're the only one there and they'll still throttle back.

Then we owners need to go about our research scientifically. We need to document the state of charge, day, date, time of day and ambient air temperatures each time we Supercharge at each particular location. We need to change our display to "energy" from "distance" to get the initial kW being delivered. Then, readings are taken after 5 minutes and every 5 minutes thereafter to see if there is some sort of pattern.

I am curious, has anyone experienced this reduction at 4-stall Superchargers, or have they only been at 6+?

 

[TaoJones]

Then we owners need to go about our research scientifically. We need to document the state of charge, day, date, time of day and ambient air temperatures each time we Supercharge at each particular location. We need to change our display to "energy" from "distance" to get the initial kW being delivered. Then, readings are taken after 5 minutes and every 5 minutes thereafter to see if there is some sort of pattern.

I am curious, has anyone experienced this reduction at 4-stall Superchargers, or have they only been at 6+?

I had a slow charge at Cheyenne once. And the charge at Needles the last time wasn't particularly speedy, but that's pretty much all I recall at the moment for slow 4-pedestal sites. The most chronically slow SC in SoCal whether full or empty for me has been the one at Oxnads.

Last time I charged at Redondo Beach, it took 1 hour and 40 minutes (100 minutes) to charge 79%.

Ordinarily, the car charges at 1% per minute (or better) there.

 

[rxlawdude]

I reported this at the Tesla Costa Mesa Sunday Social event today. The guy who was presenting seemed very interested and concerned about this. And I appreciate others who are seeing this issue and the rather dire effect it could have on Tesla adoption if not rectified.

 

[ecarfan]

We all seem to be speculating wildly here,

Agreed. And this post is a vivid example of that...

Either:

A) Tesla is intentionally throttling back their SCs to save on their electric bill

OR

B) Their SC hardware is severely flawed and already experiencing significant sustainability problems which could sink their entire Super Charger strategic plan

 

[Tony8489]

Then we owners need to go about our research scientifically. We need to document the state of charge, day, date, time of day and ambient air temperatures each time we Supercharge at each particular location. We need to change our display to "energy" from "distance" to get the initial kW being delivered. Then, readings are taken after 5 minutes and every 5 minutes thereafter to see if there is some sort of pattern.

That's a good idea, and why I quoted my Inyokern hot weather charge from June 12. And FYI I had driven the last 25 miles into Inyokern with TACC at 90mph, so I'm sure my battery was quite warm too. The more legs this thread gets, the more grateful I am that my peak Tesla travel season is spring and I'm not using Superchargers so much in summer. But if it continues it will get into the mainstream media like the Tejon backup last Dec. 26 and give Tesla a black eye.

I reported this at the Tesla Costa Mesa Sunday Social event today. The guy who was presenting seemed very interested and concerned about this. And I appreciate others who are seeing this issue and the rather dire effect it could have on Tesla adoption if not rectified.

This is an even better idea. I've been to one Sunday Social in Burbank before this issue became chronic. I'm hopeful that Brandon, the presenter that time, would pursue some answers if he were told this problem is widespread. And at Burbank on a Sunday he would have a good chance seeing it in action.

 

[apacheguy]

That would maybe explain limited charging current when all stalls are full. Throttling down when only a few cars are there doesn't get near the peak. The demand charge is once per billing cycle. So once they did peak out and get the higher charge, it's fine to go to the same level the entire month after that. I doubt Tesla building 12 stall Superchargers and then make them all slow all the time to save a little money.

Yeah, I've definitely seen throttling with only one other car present at an 8 stall location. My rate was capped to 58 kW, unpaired.

 

[Gregsbeach]

We all seem to be speculating wildly here, but there is another thread with mostly east coast experiences (search hot weather slow supercharging). We really need Tesla to be more communicative about this issue. Calling them doesn't help much, and I'm not convinced the phone support people really know what is going on. It's pretty obvious that hot weather in peak travel periods is putting stress on the SC system, the net result of which is to degrade the experience.

Of course individual disappointments are not so big a cause of concern, but the worry is that this is a systematic problem with the entire concept of highway supercharging. We'd like to think all those cars out there on a summer weekend should be BEVS, but it seems in practice that a pretty tiny fraction of them are already putting a strain on something that could be revealing a flaw in this entire plan. Tesla shoud address this, if only for the health of their stock price and ability to raise cash...

Well put....

 

[Tony8489]

This from another thread:

UPDATE: Just got off a call with Tesla. The issue is 100% known and an issue with some supercharging stations which are using newer technology. I'm being told that the issue is being investigated, and I have asked for an email reply when the fix has been identified and executed. Tesla claims that for now, the only workaround is hopping between bays as soon as the issue presents itself. In my own personal experience, one should only have to do this two or three times before reaching about 50% battery on a 90D (about 250a charge rate), which is when the issue seems to stop re-occurring after the last switch to a new bay.

 

[trils0n]

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.

 

[whttiger25]

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.

That's interesting, but I was at Gilroy just yesterday and had the 100kw to 60 kw drop happen at 30% as per usual.

 

[RandyS]

Just got back from an EV roadtrip, ecarfan...I work for the utility in San Diego, not SCE. SJC and Qualcomm superchargers are connected to the San Diego grid...