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Tesla Model S UMC cut open and modified to J1772

Discussion in 'Technical' started by TonyWilliams, May 13, 2013.

  1. TonyWilliams

    TonyWilliams Active Member

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    #1 TonyWilliams, May 13, 2013
    Last edited: Feb 15, 2014
    For information on the JESLA conversion of the Tesla Model S Mobile Connector "UMC" to J1772, please go to:

    Quick Charge Power


    If you ever wondered how the Model S UMC is so flexible and able to handle 40 amps:

    IMG_1869.jpg


    Comparison to a J1772 plug that I'm putting on the UMC:

    IMG_1867.jpg
     
  2. mitch672

    mitch672 Active Member

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    Very clever, they've doubled up on the 2 current carrying wires. Did you happen to note what guage wire they are using?
    Also, what are your plans for the now unused Model S connector? I have an OpenEVSE that could use it, if you are considering selling it.
     
  3. TonyWilliams

    TonyWilliams Active Member

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    Well, I was just going to mount it on a plaque, but it makes more sense to put it to work. Make offer.
     
  4. TonyWilliams

    TonyWilliams Active Member

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    #4 TonyWilliams, May 14, 2013
    Last edited: May 14, 2013
    Here's the J1772 plug (on the left) that I'm going to put on the UMC:

    IMG_1851.jpg


    Micro switches for switching between 150 ohm resistor or adding 330 additional ohms for the proximity pin:

    IMG_1852.jpg


    On this ITT 75 amp J1772 plug on the bottom of the picture, you can see the robust strain relief and secure clamp:

    IMG_1853.jpg


    The ITT 75 amp pins, all crimped on. You can see the blue proximity wire doubled up with its switched conductor (the blue wire goes all the way to the EVSE "box", but does nothing there). The other end of the switched conductor is connector to the green ground wire:

    IMG_1854.jpg


    The pins I'll be using on the left, ITT 75 amp pin right:

    IMG_1855.jpg



    Would you crimp or solder these? If solder, silver solder or other?

    IMG_1856.jpg


    IMG_1857.jpg


    IMG_1858.jpg


    IMG_1859.jpg
     
  5. mitch672

    mitch672 Active Member

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    Tony, if the wire is the correct gauge for the pin, and if I owned the correct crimping tool, I would crimp the pins.

    In your case, looks like you will be using 2 wires per pin, so soldering could be a better option.

    The issue with soldering is, it tends to "wick" up the copper into the insulation, melting/overheating it.
    If you have a heat sink clamp and can stop the solder from wicking up the wiring, then it can work, or if you don't mind a little melted insulation..
     
  6. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    I'm in the solder camp here, these currents are much too high to rely upon crimping as the sole measure for a mobile/active wiring connection, unless you think the strain relief guarantees immobilization. Definitely use a heat-sink clamp.

    Looks like AWG 14 conductors, if the signal pins are AWG 18. It might be 12, but even 16 would work for parallel conductors -- if you wanted to rely on them. Odd that they would go with them instead of going with 105 deg AWG 10, which is rated at 42 amps.
     
  7. TonyWilliams

    TonyWilliams Active Member

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    I hate the brittleness that happens to the copper from soldering. But, there shouldn't be much movement or vibration, so I think it will get soldered today.

     
  8. Andrew

    Andrew Model S #6151

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    Tony this is really impressive! But I'm wondering...Why are you changing the connector?
     
  9. Doug_G

    Doug_G Lead Moderator

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    Personally I'd crimp it first, and then solder it. And I'd use a heat sink clamp to protect the insulation.
     
  10. mitch672

    mitch672 Active Member

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    I can answer for him, he has a RAV4EV, and wants a portable solution to charge at 40A on the road (think RV Parks), the Model S UMC with a J-1772 connector is a way to get that done, and he can use all of the different adapters Tesla has availble.

    FYI: a the RAV4EV has an onboard 10KW charger, same as the Model S (Tesla makes it, in fact)
     
  11. Rifleman

    Rifleman Now owns 2 Model S's!!!

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    I personally think Toyota should have included a J1772 UMC with the Rav4EV instead of the plug in prius charger that it comes with, it would have made allot of sense to do so, and really would not have cost much more.
     
  12. Lloyd

    Lloyd Active Member

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    They did but it is 120V only and painfully slow.
     
  13. efusco

    efusco Moderator - Model S & X forums

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    Just another part of the RAV4EV cluster where Toyota did so many things right, but then chose to cripple so many other aspects to support their contention that "nobody wants to buy them". It's a compliance vehicle and they had no interest in large scale sales or adoption and the decision to only supply the 120v EVSE was intentional. I had the opportunity to confront some of the top people about it last year and they are completely unapologetic about the choice.
     
  14. deonb

    deonb Active Member

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    Doubling up wires to increase current is against building code for permanent installations. Are appliances exempt from this rule?
     
  15. Andrew

    Andrew Model S #6151

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    Ah, got it. Thanks Mitch! :)
     
  16. drees

    drees Active Member

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    Yeah, I find this interesting, too.

    As far as crimp vs solder, crimping is the way to go. No one uses solder for connections which will be subject to flexing vibration because of the solder wicking issue. A proper crimp will cinch down so tight on the copper that it effectively becomes solid. With a solder connection you end up with less copper-connector direct contact and for high current applications that's bad as solder has much higher resistance than copper.

    For these reasons you always see commercial grade connectors crimped, not soldered.
     
  17. TonyWilliams

    TonyWilliams Active Member

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    The prototype Rav4 EV Gen II used Roadster connectors, but the production units use J1772.
     
  18. TonyWilliams

    TonyWilliams Active Member

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    Apparently, some of the Tesla portable EVSE (Model S "UMC") are burning up? I wonder if its a lack of energy absorption from being dropped? The interchangable plug adapters are also melting their connection pins (they are tiny)?

    I'm modifying the UMC with J1772 plugs for the Rav4 but I'm bumping into a new problem. Tesla decided to use two conductors in parallel per power pin, which causes a dilemma as to how to terminate them.

    I wanted to just use a 4 indent die to crimp on the pins, but now I'm thinking that the two conductors should be combined to a single 6 - 8 gauge conductor to be crimped on the J1772 power pin. Of course, I still don't know how I would want to combine those two 12-ish gauge conductors into one 6 - 8 gauge.
     
  19. qwk

    qwk Model S P2681

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    The pins are small, but I think that the bigger problem is the gap between the adapter and the UMC. There seems to be a couple mm of play, and more at the bottom if the UMC brick is almost level with the plug(outlets mounted too low to the ground or just above a workbench).
     
  20. Ingineer

    Ingineer Electrical Engineer

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    I just did one of these conversions for Waidy:

    ?tesla-j1772.jpg

    The cool thing is Tesla's inclusion of a handy 3.3v source which is normally used for the charge door release transmitter. This enabled easy addition of a bright LED for nighttime, something not even Tesla thought of!
    ?tesla-j1772-led.jpg

    I opened one of the UMC's up, but it's a pretty destructive process due to the housing overmold and it being glued shut. If not for this "one way trip", I'd have simply replaced the thin (too thin?) Tesla cable.

    Tesla is really pushing the limits! They use two 2.5mm wires for each side, (Equivalent to #13AWG) and inside the box they use the exact same relay ClipperCreek uses on the LCS25, a single 30A rated relay. (at 40A!) It's arguable that splitting the high-current between 2 smaller conductors is better for heat-dissipation, but then you have the pesky termination issues. Inside the UMC, Tesla welds the 2 conductors to a little square terminal, then screws this to a PCB terminal. So this is a good termination and it looked well-done by my assessment. Having 4 smaller wires instead of 2 larger ones definitely makes for a smaller, more flexible cable overall, so regardless of any potential current handling gain, it's good ergonomically.

    I definitely don't like their interchangeable right-angle plug connector design. First off, if you are going to do right-angle, why not make it symmetrical? That way you could flip it 180 degrees if your outlet is installed upside-down. (Patent-Pending! =)

    Their "dongle" design makes for compact and simple plug adapters, but it ends up being a really big blob, especially when used on smaller outlets (NEMA 5-15). I think I prefer having a short length of cable for each adapter, as this makes the final plug smaller, more compact, more flexible, and spreads out heat.

    Ok, onto my conversion. Sorry, I didn't think to take pictures of the pin connection detail until it was already all assembled. Here's the best I can do:
    ?tesla-j1772-inside.jpg

    Since the "no-name" Chinese handle pins are made for much larger wire, you cannot crimp it by itself and get a reliable 40A connection. I took a crimp ferrule from a yellow butt-splice connector, and crimped the 2 Tesla wires into that, which were very well crimped, then crimped and soldered that into the no-name pin. I believe this is as good as I can make it.

    I would not trust solder alone, there must be a solid mechanical bond first at these current levels with the relatively tiny wires. If you are soldering anything, it absolutely must not be allowed to move, as you will have stress-concentrations where the solder wicking inside the wire strands ends.

    Needless to say, I'm not doing another one of these. It's a lot of work to do properly, I'm not sure I like the "no-name" Chinese handle, and the UMC itself isn't the hardiest design to begin with, though it is sexy!

    -Phil

    - - - Updated - - -

    Tony, Looks like your "no-name" handle is a new version. I'd say they've improved it. On the one I used, it appears they actually attempted to seal the housing from the weather, which is a FAIL. All they probably succeeded in doing is helping seal the water in. I solved this problem with a few well-placed holes.

    The handle release mechanism has also been simplified in yours. Mine was overly complex and fragile, and has a fatal flaw in the proximity switch system, allowing the latch to be disengaged without tripping the switch. Luckily the good design of J1772 is somewhat double-redundant in this area, so it's not a big deal.

    -Phil
     

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