New device installed at Tannersville Supercharger

[yobigd20]

this supercharger was down last week. I ended up running out of juice trying to get home (first time in 140k miles) bc this site was down and I did not have enough to make it home. Side note: I can personally vouch for there being absolutely no reserve when you hit 0. In fact, right after it hit 0 I got the "pull over safely car shutting down" message, and was surprised that it only gave me about 50 feet or so before it came to a stop. Not much room at all.

ANYWHO regardless of that tragic experience, I'm back at tannersville right now. I always charge at the same stall and am here many times a week sometimes twice a day. When I arrived Last week when it was down they had the whole thing torn apart and said it could be a few days of it being down. I'm not quite sure what they were doing, as I thought they said that the transformers on the pole were shot, though I have no idea why as there were not any local storms or anything, plus they said they were NOT Tesla folks but instead power company guys. That didn't really make sense to me as they were tearing apart the supercharger cabinets, not working on the transformers on the pole. So my whole point to this thread is this - there is some new device installed here now that wasn't here before and I'm just wondering what it is or if it's some kind of power upgrade for the future. Uploading pics...

 

[scaesare]

Those are 3-phase transformers. Looks like the have one 480V/192A unit per supercharger cabinet, as opposed some installations which have 1 larger transformer routed through switchgear that feeds all of the cabinets.

That would seem consistent with the statement that the existing transformers aren't cutting it...

 

[ecarfan]

@yobigd20 thanks for your report! Very interesting development. I note that the first photo you posted shows the hardware is manufactured by "Quality Transformer and Electronics", located in Milpitas CA. Literally next door to Fremon CA. That would be this company Quality Transformer and Electronics: Custom Transformer and Electrical Assembly Manufacturer

As @scaesare notes, perhaps this is related to the slow charging issue experienced by some owners, and is an attempt by Tesla to address the problem.

 

[miimura]

The question is, why are they bucking the voltage by 4.8% after the utility transformer? Why aren't there different taps on the utility transformer to bring the voltage into spec?

 

[TexasEV]

Was this location one of those experiencing slow charging rates?

 

[bak_phy]

Was there any indication on your display that the SC was down? How far did you have to go from there?

 

[arg]

The question is, why are they bucking the voltage by 4.8% after the utility transformer? Why aren't there different taps on the utility transformer to bring the voltage into spec?

It is possible they are doing it the other way around - dropping the voltage.

Maybe the utility power at this location occasionally peaks too high and causes the superchargers to shut down for overvoltage? Could possibly arise if the utility transformer is tapped up to supply some other heavy user, and then the voltage overshoots on the weekend or whenever that user isn't operating?

 

[miimura]

It is possible they are doing it the other way around - dropping the voltage.

Maybe the utility power at this location occasionally peaks too high and causes the superchargers to shut down for overvoltage? Could possibly arise if the utility transformer is tapped up to supply some other heavy user, and then the voltage overshoots on the weekend or whenever that user isn't operating?

The device being discussed is a Buck-Boost Transformer. You can run it either way, dropping the voltage (buck) or increasing the voltage (boost). I went and looked at the forum thread for this Tannersville site and they are using pole-top transformers, 3 each 167kVA cans. This is somewhat unusual for a 8 stall American site. Usually, they use a single pad mounted 500kVA 3-phase transformer, which could be tapped for slightly different voltages. The pole-top transformers have a fixed ratio, so it could be putting out a slightly high voltage, which they must have discovered, is causing a problem for the Superchargers. Anyway, based on the sizing and voltages, they're not sharing the transformers with anyone else. It's an outlet mall, so it's unlikely there's any other need for 480V 3-phase power.

 

[arg]

Anyway, based on the sizing and voltages, they're not sharing the transformers with anyone else. It's an outlet mall, so it's unlikely there's any other need for 480V 3-phase power.

But they will be sharing the HV feed, presumably with the mall. If this is a somewhat rural location, with the HV feed coming from a long way away, you can imagine the load of the mall siginficantly affecting the voltage when all the stores close.

 

[SomeJoe7777]

The other interesting thing is that this device is an autotransformer. Autotransformers use shared windings on the core for both the primary and secondary. This has the disadvantage that it does not provide isolation between the primary and secondary, but the advantage that the transformer core only needs to be sized proportional to the difference in current between the primary and secondary instead of proportional to the total kVA. This means that the autotransformer can be very small for the amount of power it's carrying. For this reason, autotransformers are routinely used where there needs to be a small boost or cut (buck) in voltage at high power levels.

 

[Chrisizzle]

Side note: I can personally vouch for there being absolutely no reserve when you hit 0. In fact, right after it hit 0 I got the "pull over safely car shutting down" message, and was surprised that it only gave me about 50 feet or so before it came to a stop. Not much room at all.

I have had a different experience. On two occasions I had to run past zero range.

My guess is maybe 2km on a Model S two years ago and 4km on my current Model X three days ago.

I don't want to turn this into a zero range thread but I'm curious how you got home. Did Tesla roadside help, or were you on your own since it was 'user error'?

 

[yobigd20]

I don't want to turn this into a zero range thread but I'm curious how you got home. Did Tesla roadside help, or were you on your own since it was 'user error'?

i got so close to my house it shut down in the middle of the road almost in front of my house and i was able to daisy chain 2 100ft extension cords and pull 7A 104V and it took about an hour before the car errors were cleared before I could put the car back in drive and pull in my driveway. it was still showing 0 on the display. is there any way to put the car in neutral in this scenario? they car display was on 'D' and it wouldnt let me shift it into neutral. wouldn't even let me go into Park either (weird). i would have tried to push it in the driveway if i could get it into neutral, but i couldn't and it took so long that one of my neighbors actually called the cops on me (random). i guess they thought i was suspicious. it was pitch black out.

 

[yobigd20]

@yobigd20 perhaps this is related to the slow charging issue experienced by some owners, and is an attempt by Tesla to address the problem.

this is a very rarely used location. i'm there so often many times and week, and 98% of the time i'm the only one. only rarely have i ever seen another tesla pull in, and never more than 2 (including me) at a time. i've never had a problem charging in this location before or it's charge rates either as i regulately would get 100+ kW on it. it would seem odd to me that there were any issues here that would warrant fixing, unless something happened that day that disabled it completely.

 

[arg]

s there any way to put the car in neutral in this scenario?

Tow mode from the Settings->Service&Reset menu?

 

[Ulmo]

Those are 3-phase transformers. Looks like the have one 480V/192A unit per supercharger cabinet, as opposed some installations which have 1 larger transformer routed through switchgear that feeds all of the cabinets.

That would seem consistent with the statement that the existing transformers aren't cutting it...

...and also consistent with the statement that the workers had the SuperCharger cabinets open and the site "torn up" as opposed to working directly on the pole, since they were re-wiring and re-routing through the new one-per-charger buck-boost transformers on the side, in addition to (most likely due to discussion), or rather than (less likely due to the discussion), the one-for-all setup before. Perfect explanation, in fact.

The question is, why are they bucking the voltage by 4.8% after the utility transformer? Why aren't there different taps on the utility transformer to bring the voltage into spec?

Another poster here said it is a remote area with a mall in it and nothing else. Perhaps the utility sized the delivery for many more future users, such as more residential development around the mall, and so far, that use has not materialized. That doesn't exactly make sense, though, since that would mean the voltage would swing pretty high and low as the usage went up and down throughout the day. Maybe the utility just threw something together that "just works" for now, and will return to upgrade it later. Maybe the utility thought the chargers would handle a wider spec than they actually can. That is odd to me that they can't: why can't the chargers handle higher voltage ranges close to regular voltages? That 504Vrms doesn't seem that far away from 480Vrms. Is this a case of computer programmers sitting at a desk in Palo Alto inputting numbers from their manual, and no electrical engineer told them "hey, you can allow up to xVrms without problem"? Or of some UL listing somewhere that restricts them legally or in insurance despite it being electrically just fine? More corporate or government BS, in other words?

Tow mode from the Settings->Service&Reset menu?

Or, get the Tow Mode PDF from Tesla's web site, and read how to tow a disabled Tesla (even without battery). There must be some type of instructions in there. Isn't there some type of release somewhere? I surely hope using a crane isn't the only way to tow this type of Tesla.

 

[Missile Toad]

@yobigd20 Have you noticed any improvement in charging speeds since the upgrade? Locally, at the N. Houston SuperCharger, I've been told that some work is being done on transformers by the local utility. Because the N. Houston site is also a show-room/service-center, I think they hide the transformers within the show-room / service center -- so we have 0 visibility as to things getting dis-assembled and re-assembled.

 

[yobigd20]

@yobigd20 Have you noticed any improvement in charging speeds since the upgrade?

no, as i never had any problems charging here before.

 

[yobigd20]

Charging here now. Seems to get up to around 120kW just fine.