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Schmelted UMC/NEMA 14-50

Discussion in 'Model S: Battery & Charging' started by yobigd20, Jun 19, 2013.

  1. yobigd20

    yobigd20 Well-Known Member

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    Just had my UMC + NEMA 14-50 replaced today. Schmelted the old one. It still worked, but clearly faulty.

    schmelted_umc.JPG
     
  2. EdA

    EdA Model S P-2540

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    melting

    Any reason/explanation given???
     
  3. Al Sherman

    Al Sherman It's about THIS car.

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    How'd that happen?
     
  4. yobigd20

    yobigd20 Well-Known Member

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    Not really sure - I have the newer style adapter and this should not happen with it. Only reason I discovered it was during a conversion with a Tesla rep that they were replacing all the original adapters with newer ones. We inspected my NEMA 14-50 and I had the newer version already (the old version were earlier than my vin, so most people have the new ones already, must be earlier than 5k vins)).

    Anywho, upon looking inside it we found it melted both the adapter and UMC. He was very surprised to see that I had the new one and yet this still melted. He did mention something like when you click the adapter onto the UMC that it needs to be fully clicked in - no gaps. He mentioned something like the metal clip in the original was flimsy and sometimes this wouldn't snap on fully and if that happens and there is a gap between the adapter and UMC it causes it to melt like that. This should be fixed with the new adapters but clearly not as mine was already melted and he's definitely never seen it happen with the new ones until mine...
     
  5. brianman

    brianman Burrito Founder

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    When I went to get my tires rotated, I got replacement adapters for 14-50 and J1772.

    My understanding/recollection is that the 14-50 replacement was to deal with the melting issue while the J1772 was just that some cars and/or stations had fitting issues.
     
  6. capt601

    capt601 Vin02324

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    How do you tell if you have the old or new adapter?
     
  7. brianman

    brianman Burrito Founder

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    #7 brianman, Jun 20, 2013
    Last edited: Jun 20, 2013
    The J1772 versions have different TPNs (part numbers).
    As for the 14-50, my new one has...
    ... on it. I presume the original ends with "A". But that's just a guess as I don't have my original one.
     
  8. capt601

    capt601 Vin02324

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    Thanks. I'll search around in the threads. Took delivery in December so I'm guessing I may have the earlier version? Maybe I'll just take them into the service center and ask them.
     
  9. brianman

    brianman Burrito Founder

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    @capt601 - Reread the updated post. :)
     
  10. FlasherZ

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

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    I had one of the newer 14-50 adapters too when mine was replaced. It just appears that over time, some UMC's are not making full contact and it's generating heat.
     
  11. waidy

    waidy Member

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    May be the best way is to forget about using UMC charging at 120V. Cut the end of the AC plug and wire to a Home Depot 14-50 plug.
     
  12. yobigd20

    yobigd20 Well-Known Member

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    what? totally didn't understand that statement.
     
  13. Alpha

    Alpha Member

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    I was just pondering today- the UMC and cable sure does get hot - couldn't they make a bigger, thicker version that would stay cool?
    Sure it would be more bulky, but I wouldn't mind that since it stays fixed in my garage 99% of the time (and I could still keep the current, more portable version for road trips...)
    I would think the cost savings over time (in less wasted electricity) would add up! So surely that's worth something...
    Correct me if I'm way off...
     
  14. montgom626

    montgom626 Active Member

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    I lose 3 kW per day from vampire loads. UMC is irrelevant when it comes to kW lost.
     
  15. waidy

    waidy Member

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  16. qwk

    qwk Model S P2681

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    ^^^That might solve the melting problem, but not the UMC malfunction problem.

    BTW, the old 14-50 adapter does have a part number that ends in A. The new ones have a B.
     
  17. Alpha

    Alpha Member

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    Charger has been measured to be only 86% efficient, thats way more than 3kW per day of loss! Some of that is probably from the rectifiers in the car not being 100% efficient, but some is also probably from the heat loss.

    And besides, vampire load will be fixed by end of year (or so I've heard.)
     
  18. brianman

    brianman Burrito Founder

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    Thanks for the confirmation, qwk!
     
  19. capt601

    capt601 Vin02324

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    Thanks!
     
  20. FlasherZ

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

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    The adapters contain components (mostly resistors) that tell the UMC what type of a plug is connected. You'd have to duplicate those too, if you wanted to hardwire a specific plug onto it.

    - - - Updated - - -

    Correct, although my rev B adapter is what melted. I've since gone to the HPWC, so I don't use my UMC anymore except on the road to tell you my experiences.
     

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