Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Tesla Model S UMC cut open and modified to J1772

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,028
1,025
The UMC doesn't know 120v from 240v - my tests for the 20A maximum are based upon me moving the neutral to a hot pin and presenting 120V on a NEMA 14-50. The failure you got was odd, though -- when I reverse polarity, I get a red code for ground fault. I suspect Tesla is measuring ground vs. that one specific hot to make sure they're not at same potential (roughly). So no idea what triggered the 8 blinks...
 
The UMC doesn't know 120v from 240v - my tests for the 20A maximum are based upon me moving the neutral to a hot pin and presenting 120V on a NEMA 14-50. The failure you got was odd, though -- when I reverse polarity, I get a red code for ground fault. I suspect Tesla is measuring ground vs. that one specific hot to make sure they're not at same potential (roughly). So no idea what triggered the 8 blinks...


Yes, we did the "20 amp test" over a year ago the same way. A dumb limit that serves no purpose. The search for replacement NEMA 14-50 Tesla plugs goes on.
 

Cosmacelf

Well-Known Member
Mar 6, 2013
9,022
23,717
San Diego
Yes, we did the "20 amp test" over a year ago the same way. A dumb limit that serves no purpose. The search for replacement NEMA 14-50 Tesla plugs goes on.

It seems that late model cars do not have the 20A limit. A few people who got their cars this year have reported that they can charge at greater than 20A with 120V. It is either a hardware change in the car charger, or a firmware update that doesn't get updated via OTA updates. I'm guessing the latter, but I haven't been back to a service center recently to ask them if they can update my car charger firmware...
 
It seems that late model cars do not have the 20A limit. A few people who got their cars this year have reported that they can charge at greater than 20A with 120V. It is either a hardware change in the car charger, or a firmware update that doesn't get updated via OTA updates. I'm guessing the latter, but I haven't been back to a service center recently to ask them if they can update my car charger firmware...

Toyota Rav4 EV will never get this update. When I get my hands on a Mercedes B-Class ED, that will be one of the things I check.
 
I did cut open the Tesla NEMA 14-50 plug with the failed connection within "Line 2" (the red wire):


TeslaUMC1450cutopen1.jpg




TeslaUMC1450cutopen2.jpg




TeslaUMC1450cutopen3.jpg




TeslaUMC1450cutopen4.jpg




TeslaUMC1450cutopen5.jpg




TeslaUMC1450cutopen6.jpg




TeslaUMC1450cutopen7.jpg




TeslaUMC1450cutopen8.jpg




TeslaUMC1450cutopen9.jpg




TeslaUMC1450cutopen10.jpg




TeslaUMC1450cutopen11.jpg
 
Help!

I'm not very technical. I've been reading these posts about J1772, but I'm not really sure what I need. I have a 2011 Tesla Roadster and I just bought the "CAN" from Henry Sharp. I have solar at my house and they installed an outdoor plug for me that's basically a clothes dryer type of outlet. I had a 2008 Roadster and the standard Roadster cable from Tesla plugged right in. It was the big $1500 cable. I wish I kept it when I sold the car!

Ideally I'd like the Model S-type cable to run from my house, through the CAN, and into the car. I understand Tony might be selling a cable that does this? Is it the JESLA cable? I should be able to figure this out on my own, but I want to be sure before I start spending money willy-nilly.

Thanks!

-Dr. Chako

PS. I tried to DM Tony, but his mailbox is full.
 

AEdennis

Active Member
Jul 23, 2013
2,719
948
Help!

I'm not very technical. I've been reading these posts about J1772, but I'm not really sure what I need. I have a 2011 Tesla Roadster and I just bought the "CAN" from Henry Sharp. I have solar at my house and they installed an outdoor plug for me that's basically a clothes dryer type of outlet. I had a 2008 Roadster and the standard Roadster cable from Tesla plugged right in. It was the big $1500 cable. I wish I kept it when I sold the car!

Ideally I'd like the Model S-type cable to run from my house, through the CAN, and into the car. I understand Tony might be selling a cable that does this? Is it the JESLA cable? I should be able to figure this out on my own, but I want to be sure before I start spending money willy-nilly.

Thanks!

-Dr. Chako

PS. I tried to DM Tony, but his mailbox is full.

Dr. Chako,

If you are using a CAN to plug in your Roadster, the JESLA (which TonyWilliams sells on Quick Charge Power) is one of the many things you can charge your Roadster with. It is a Model S MC (plug) that has been modified to use J1772 (the charger standard that the CAN adapts the Roadster to)).

Therefore, you should be fine.
 
Hi,

Can someone advise me how the Tesla (car) knows what sort of power supply it is connected to and therefore how much current the car can pull? Does the Tesla car-side plug use a resistor between earth and the Proximity Pin like the 61296 Type 2 (Mennekes) plugs use? If so which resistor is this on the J1772 circuit in Post number 62 of this thread?

Regards, Martin Winlow.
 

arg

Active Member
Supporting Member
Aug 22, 2012
1,817
1,821
Cambridge, UK
Can someone advise me how the Tesla (car) knows what sort of power supply it is connected to and therefore how much current the car can pull? Does the Tesla car-side plug use a resistor between earth and the Proximity Pin like the 61296 Type 2 (Mennekes) plugs use? If so which resistor is this on the J1772 circuit in Post number 62 of this thread?

It uses the pilot signal (pin 4 in that diagram in post #62). This is common across Roadster/Model-S-USA-connector/J1772/IEC-type-2 connectors in both USA and European models - they all have the pilot signal on one of their pins with the same specification. It is a square wave signal generated by the EVSE, where the mark/space ratio indicates the available current. The same pin conveys information in the opposite direction: the car adds a load to it, changing the peak voltage, which the EVSE uses to know (among other things) when to turn on the power.

Resistors in the plug to indicate current capability are a different function: with a removable cable (as commonly used with type2 cables in Europe), you might have an EVSE and a car both capable of (say) 32A, but only a 16A cable connecting them together. The type2 cables provide a resistor on the 'proximity' pin at the EVSE end to indicate the cable rating, and the EVSE uses this to control what it puts on the pilot signal - to be the lower of either the cable's rating or the EVSE's own supply limit. J1772 doesn't have this resistor coding, as J1772 cables are always hard-wired.

BTW, this is why you can't use multiple type2 cables daisy-chained together: the EVSE would only know the rating of the one nearest to it, and other cables in the chain might be lower rated. To stop you doing this (which looks at first glance like it should be possible), the pilot pins in some versions of the type2 connector are made shorter such that they don't connect at all with daisy-chained cables. You then have Roadster owners using sawn-off type2 connectors to defeat this protection so that they can use a separate cable on type2 charge points with tethered cables...
 
Last edited:
  • Informative
Reactions: Ulmo
J1772 doesn't have this resistor coding, as J1772 cables are always hard-wired.

Hi. Thanks for the reply. I assume from the above quote you mean 'hard wired to the EVSE'? If so, as you may be aware, in the EU we have lots of Type 2 (Mennekes) sockets of varying outputs - well, either single phase 240VAC at either 16A (~3.8kW) or 32A (~7.6kW), or 3 phase 240VAC at 32A on each phase (43kW). These are compatible with our J1772 EVs by using an adaptor cable with J1772 (Type 1) on one end and Type 2 on the other. The Type 2 end uses the IEC 61296 resistor between PP and earth for current control. I suppose the advantage is that you can then use the Type 2 EVSE socket with either a T2 to T1 cable OR a T2 to T2 cable catering for all EVs… including the EU/UK Tesla Model S which has a T2 socket on it for charging rather than the US type plug/socket.

So my next question is: Would it be possible to use an adaptor with an EU spec UMC with a T2 *socket* on one end and a standard EU 240VAC 'mains' plug on the other (plug would be country specific)? This would require, I assume, the Model S' charger to be manually dialled back to draw less than 13A (less than 10A would be better) or otherwise the fuse in the 'mains' plug would blow or, if it is a country's plug that has no fuse, cause the plug to overheat… MW
 

arg

Active Member
Supporting Member
Aug 22, 2012
1,817
1,821
Cambridge, UK
Hi. Thanks for the reply. I assume from the above quote you mean 'hard wired to the EVSE'? If so, as you may be aware, in the EU we have lots of Type 2 (Mennekes) sockets of varying outputs - well, either single phase 240VAC at either 16A (~3.8kW) or 32A (~7.6kW), or 3 phase 240VAC at 32A on each phase (43kW). These are compatible with our J1772 EVs by using an adaptor cable with J1772 (Type 1) on one end and Type 2 on the other. The Type 2 end uses the IEC 61296 resistor between PP and earth for current control. I suppose the advantage is that you can then use the Type 2 EVSE socket with either a T2 to T1 cable OR a T2 to T2 cable catering for all EVs… including the EU/UK Tesla Model S which has a T2 socket on it for charging rather than the US type plug/socket.

Sorry, I should have said something like "all pure J1772 systems" - the point being that there's only ever one J1772 connector pair between EVSE and car (and the J1772 specification therefore doesn't have anything in it to cope with detachable cables), while Type2 connectors permit detachable cables with (approximately) the same connectors at each end. The detachable cable support is documented only in the IEC specifications.

So my next question is: Would it be possible to use an adaptor with an EU spec UMC with a T2 *socket* on one end and a standard EU 240VAC 'mains' plug on the other (plug would be country specific)? This would require, I assume, the Model S' charger to be manually dialled back to draw less than 13A (less than 10A would be better) or otherwise the fuse in the 'mains' plug would blow or, if it is a country's plug that has no fuse, cause the plug to overheat… MW

Adapter to what? The EU spec UMC obviously connects direct to EU spec Model S at the car end, and already has standard mains plugs of one sort or another on the other end.

Adapters to other types of mains plug such as UK 13A BS1363? Yes, lots of people do this already, with the limitation you mention about manually dialling down the power depending on the exact combination of plugs.

Adapters to allow the Tesla Model S UMC to be used with non-Tesla J1772 vehicles or Roadsters? Theoretically straightforward, but won't work with off-the-shelf type2->type1 cables. You either need to 'saw off' the type2->type1 cable as Roadster users have been doing to get access to the Ecotricity points with tethered cables, or buy the type2 vehicle-end connector (only made in chassis-mount styles) and mount it in some kind of box to build your adapter.

Suspect I'm misunderstanding your question here.
 
Last edited:
Guys,

Would any of you know if it is possible to have a European style Type 2 connector signal the car to stop charging and release the lock by adding a resistance? The European UMC does this, so I guess it should be possible...
Since the type 2 connector already has a certain resistance set for detecting the wire diameter, the question is what that resistance should be?

Any help would be grrrrreatly appreciated!

Erwin
 

arg

Active Member
Supporting Member
Aug 22, 2012
1,817
1,821
Cambridge, UK
Guys,

Would any of you know if it is possible to have a European style Type 2 connector signal the car to stop charging and release the lock by adding a resistance? The European UMC does this, so I guess it should be possible...
Since the type 2 connector already has a certain resistance set for detecting the wire diameter, the question is what that resistance should be?

Any help would be grrrrreatly appreciated!

Erwin

It is debatable what the 'correct' thing to do is, but it certainly works with the Model S if you keep the existing resistor and insert a normally-closed switch in series with it: press the switch and the car unlocks the port.

I have my charging cable at home modified like this.

It is not clear why the IEC standards require the resistor that denotes the cable rating to be fitted at both ends of the cable - it is the resistor at the EVSE end which controls the pilot signal sent to the car, so the car has no reason to read the value of the resistor on the proximity pin at the other end. Possibly it would be more correct if you put an additional 330R in parallel with the normally-closed switch (which would make it the same as J1772), but I haven't tried that.
 

markb1

Active Member
Feb 17, 2012
3,092
720
San Diego, CA
It is not clear why the IEC standards require the resistor that denotes the cable rating to be fitted at both ends of the cable - it is the resistor at the EVSE end which controls the pilot signal sent to the car, so the car has no reason to read the value of the resistor on the proximity pin at the other end. Possibly it would be more correct if you put an additional 330R in parallel with the normally-closed switch (which would make it the same as J1772), but I haven't tried that.

I'm not at all familiar with this standard, and I have no idea why the cable would need two resistors built into it. But I would think that both the cable and the EVSE would each need pilot signals, as the charger needs to know not to pull more current than the lower rated of the two. With J1772, the cable is permanently attached to the EVSE, so only one pilot signal is necessary.
 

arg

Active Member
Supporting Member
Aug 22, 2012
1,817
1,821
Cambridge, UK
I'm not at all familiar with this standard, and I have no idea why the cable would need two resistors built into it. But I would think that both the cable and the EVSE would each need pilot signals, as the charger needs to know not to pull more current than the lower rated of the two. With J1772, the cable is permanently attached to the EVSE, so only one pilot signal is necessary.

As you say, J1772 always has tethered cables and things are straightforward: the Control Pilot is generated by the EVSE and indicates the maximum current that can be drawn; it is carried in a core in the cable (and serves a secondary purpose of ensuring that the safety earth connection is intact). The Proximity Pilot is used to detect the connector being disconnected and also for a button/lever on the connector to signal that the user wants to disconnect it; this connection is entirely in the connector (with 2 resistors) and does not travel down the cable.

The IEC standard with type2 connectors has the same CP and PP pins, and still has only one signal wire in the cable (in addition to power and earth), but now the cable is not always captive. CP works exactly as in J1772 and signals to the car the power that it is permitted to draw. CP still serves the accidental-unplug function, but now the resistor value rather than being fixed has a choice of values to represent the current carrying capacity of the cable. This resistor is specified to be at _both_ ends of the cable. The resistor at the EVSE end of the cable (assuming a non-tethered cable connecting to a socket on the EVSE) has an obvious purpose: it tells the EVSE the rating of the cable. The EVSE then reflects this in what it signals to the car on the CP: the lower of the EVSE's own rating and the cable rating. The resistor value at the car end has no obvious purpose - the car does not need to know the cable rating, as this is already reflected in the CP signal by the EVSE.
 

hcsharp

Active Member
Jun 7, 2011
3,429
1,519
Vermont
...
This resistor is specified to be at _both_ ends of the cable. The resistor at the EVSE end of the cable (assuming a non-tethered cable connecting to a socket on the EVSE) has an obvious purpose: it tells the EVSE the rating of the cable. The EVSE then reflects this in what it signals to the car on the CP: the lower of the EVSE's own rating and the cable rating. The resistor value at the car end has no obvious purpose - the car does not need to know the cable rating, as this is already reflected in the CP signal by the EVSE.

I interpreted that to mean it has to be able to detect the resistor value at both ends of the cable, not that a separate resistor is needed at each end. Installing 2 resistors is likely to create a larger hazard than only one. Did I miss something?
 

arg

Active Member
Supporting Member
Aug 22, 2012
1,817
1,821
Cambridge, UK
I interpreted that to mean it has to be able to detect the resistor value at both ends of the cable, not that a separate resistor is needed at each end. Installing 2 resistors is likely to create a larger hazard than only one. Did I miss something?

There's no core in the cable, so there has to be a resistor at each end (wired from PP to GND within the connector). Certainly all standard type2 cables are wired like this, and even tethered cables have the resistor from PP to GND at the car end.

Last time I looked this up, I am sure I found a requirement for the EVSE to read the resistor at its end and modify the CP as required, but there didn't appear to be a requirement for the car to read the value on PP at that end - which then raises the question as to why that resistor is required to be there. Obviously some value of resistor is required - as in the J1772 case - to allow the PP to serve its proximity-detect function, but that could just be a fixed value like J1172.

Possibly I have missed a requirement somewhere - I will go and read the standards again.

Conversely, even if you believe there's a reason to have the cable-rating-specific resistor at the car end, there's no reason why the J1772 charge terminate switch on the PP couldn't have been implemented (car sensing a change in the value during a session to indicate an unplug request).
 
They did but it is 120V only and painfully slow.
That actually brings me to a point in which i wanted to voice to tesla. Make their UMC With J1772 outlets Most electric vehicles, or extended range vehicles, chevy volt. nissan leaf, ford focus ev, and fiat ev., fit ev all have "chargers" included with them on 120volts and then to get a "fast charging time" they force you to buy a charger from one of their exclusive ev partnered affiliates that are upwards of 700 dollars for what is essentially a 240 volt circuit that tesla includes with their vehicles for free... if ev adoption is to happen quickly the minimum that should be included is a UMC of tesla handling 10kwh the instillation cost are reduced for home owners to Simply have an electrician make an outlet. It obviously has to do with energy density of tesla vehicles vs the competition but i think having the um be able to work with all ev's is a big step forward
 

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top