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Will UMC be damaged if left plugged in for extended time?

Discussion in 'Model S: Battery & Charging' started by cplaw, Sep 13, 2016.

  1. cplaw

    cplaw Member

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    I have set up my UMC such that it remains plugged into the NEMA 14-50 outlet at all times. Will leaving it plugged into the outlet for extended periods of times (like months at a time without removing it) cause damage to the UMC or some sort of degradation of the UMC's output?

    Should I give it some "rest" time?
     
  2. cmorgan

    cmorgan Member

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    I can't imagine you'd need to rest it. The umc is likely to wear due to relay cycles (if it has a relay inside of it), and heat, which tends to degrade everything from chips to capacitors to wires. But, since it isn't charging the car during these idle times it wouldn't be heating up any. I'd imagine it is perfectly fine being plugged in and unused for months or years.

    I'm guessing you'd have the added advantage of reducing receptical plug/unplug cycles which should make it last longer.
     
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  3. cplaw

    cplaw Member

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    So it sounds like you're suggesting it is actually better to leave it plugged in for extended periods? Just want to make sure I'm understanding the response correctly.
     
  4. mhan00

    mhan00 Member

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    Leave it plugged in. You'll probably do more damage over time to your outlet or the UMC plug pulling it out and plugging it back in than you would just leaving it plugged. It shouldn't be drawing any power unless you're charging unless something goes massively wrong.
     
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  5. cmorgan

    cmorgan Member

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    Yep. Bonus is that you'd also reduce wear on the receptical by leaving it plugged in.

    Also consider that the hpwc is always powered even when not charging the car.
     
  6. HankLloydRight

    HankLloydRight Fluxing

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    My UMC is plugged in 100% of the time. No problems after 2.5 years.
     
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  7. Cosmacelf

    Cosmacelf Active Member

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    In theory, some electronic components inside the UMC like electrolytic capacitors would last longer if it wasn't plugged in. But we are talking about extending the lifetime of something that will probably be obsolete before it dies from old age, so not much worry there. And it'll consume about $0.05 of electricity per year on standby, so no worries there either. So, no reason to unplug it that I can think of.
     
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  8. TexasEV

    TexasEV Active Member

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    No problem leaving it plugged in. The Mobile in UMC is a capability, not a requirement.
     
  9. GSP

    GSP Member

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    Most owners who post here at TMC that don't have an HPWC, leave their UMC plugged in all the time except for trips a few times per year. I am sure that is how Tesla intended it be used.

    Enjoy your Tesla!

    GSP
     
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  10. Boatguy

    Boatguy Member

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    @mhan00 nailed it. The wear on the plug would be much worse than the wear on the UMC electronics.
     
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  11. cplaw

    cplaw Member

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    Sounds like there's a consensus on this, thanks.
     
  12. thecloud

    thecloud As rhythm raced inside, the ship came alive

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    Count me as another one who leaves the MC (note: it's been just "Mobile Connector" for quite a while, not UMC) plugged in all the time. No problems with it over the last 2 years.

    The title of this thread could have benefited greatly from a question mark at the end. As it stands, it's making a statement that's basically clickbait: you read it and think there's some damage that will occur by leaving it plugged in. That is not the case. :(
     
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  13. cplaw

    cplaw Member

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    Sorry about leaving out the question mark; I realized that mistake shortly after posting, but didn't know how to edit to add in the question mark in the title.
     
  14. GoTslaGo

    GoTslaGo Learning Member

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    You can always report your post, and ask the mods to add the question mark. I think that would work.

    Also to answer your question. We leave one UMC plugged in at all times, and have a spare in the car itself (for trips). Less wear on the connection. We use a 14-30 so we cannot use the new "permanent" 14-50 UMC available now.
     
  15. kort677

    kort677 Active Member

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    do you leave your refrigerator plugged in all the time without any worries? same concept. my umc has been plugged in for years with no apparent ill effects
     
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  16. JPP

    JPP Active Member

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    Our 2 MCs have been continuously plugged in since delivery (so mine over 3 years) with rare disconnects to take it travelling as needed. No failures. FWIW, I chose to buy an extra NEMA 14-50 adapter to keep in the black bag. When I take the MC, I disconect at the adapter, and do not remove the (original) NEMA 14-50 from the wall receptacle. Less wear and tear on the receptacle-but more on the MC-adapter interface.
     
  17. joebiker25

    joebiker25 Member

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    I just picked up my new MS yesterday and had the same question. Thank you all for reassuring me that it is ok to leave the UMC plugged into the NEMA 14-50.
    Is there any way to rest the large and heavy (transformer?) unit with the Tesla logo and green light so it doesn't put continuous strain on the plug and receptacle? I have ordered the Tesla cable organizer. Here is a pic of what I am referring to...I would love to see any pics of similar setups.
    Thanks in advance!
    [​IMG]
     
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  18. thecloud

    thecloud As rhythm raced inside, the ship came alive

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    1. Click on the magnifying glass icon at the top right.
    2. In the search box, type "UMC holder".

    For your setup, I'd think a water bottle cage for a bicycle, mounted to the wall just to the right of the conduit, would be a good solution.

    My solution: I have a shelf next to my NEMA 14-50 outlet, which the MC rests on.
     
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  19. GoTslaGo

    GoTslaGo Learning Member

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    See @thecloud 's post above. That being said, we just hang our UMC like your picture. We've done that since we bought the Tesla (Oct/Nov 2015) with no problems. We leave it plugged in and have an extra UMC in the car for emergencies and traveling.
     
  20. Chris TX

    Chris TX Active Member

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    I've had mine plugged in for almost 3 years, with the exception of long road trips. Recently, it's been getting hotter at higher amp settings which throttles the amps down a bit, though. 147F is the highest I've seen on the controller box.
     
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