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UMC Overheats

Discussion in 'Roadster' started by Tesla 940, Oct 24, 2016.

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  1. Tesla 940

    Tesla 940 Member

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    For a while now my UMC gets warm/hot when it is plugged in - NOT even plugged into the car or charging - simply plugged into the 40/240 outlet. I put an IR to it and the surrounding areas and measured a 20 -25 degree difference on the front of it and a 30 degree difference on the back of it. When it is actually charging it gets even hotter and will "trip" frequently.

    I know this is not normal but I don't know if it is common. Do I need a new one?

    Anyone willing to share info is appreciated.

    Don
     
  2. thecloud

    thecloud As rhythm raced inside, the ship came alive

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    Yes, it's common for the UMC to get hot when charging continuously at its maximum 40 amp rate. Many people, myself included, turn down the charging rate (on the charging screen in the car) so it only pulls 32 amps. This keeps the UMC running cooler, and may help to prolong the lifespan of its components.

    (Just noticed this was posted in the Roadster forum, not Model S/X, so adjust expectations as needed.)
     
  3. sethr

    sethr CPO Roadster #1089

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    The UMC does indeed get rather warm just plugged in, doing nothing. Before I got my HPWC, I positioned a small fan to blow on the UMC, and that helped a good bit. My first two only lasted a month or so each (replaced under warranty back then), but then with the fan, it lasted a year and a half before I got my HPWC, and was fine the last time I used it. I also do agree with the previous post; charge at the lowest amperage that you have time for.
     
  4. wiztecy

    wiztecy Active Member

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    I'd toss that crappy Roadster UMC in the trash, cut the Roadster cable end off and have a JuiceBox or OpenEVSE built. End of story and you'll have a reliable charge source that's not overheating. If you want something for portability pick up the Model S UMC and pair it with the CAN SR. However I'd say the Model S UMC is a tad better in quality than the Roadster UMC and I wouldn't rely on it if you want it to be a dedicated home charger. I run both, the Model S UMC is stowed in the Roadster for trips and my JuiceBox is dedicated as my home charger. I can charge up to 80 amps off the JuiceBox if I wanted to pull that much, of course the S can utilize the 80amps where the Roadster is limited to 70amps. The JuiceBox has a solid built and has a steel fireproof case that the houses the electronics.
     
  5. Msjulie

    Msjulie Member

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    I can 2nd a positive experience with a JuiceBox though since my house is older and the amperage available 'minimal', mine can only supply 40amps and my roadster seems to have decided to pull 36. Still easily recharges overnight w/o any worry.
     
  6. Tesla 940

    Tesla 940 Member

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    Thanks for the replies. A Can SR is NOT an option because my car is one of a handful that it does not work with (the Can JR is fine). I'll look into the JuiceBox. I periodically need to charge away from home and the 50amp outlet is what is available - either at RV campgrounds or Willow Springs racetrack.

    Again, thanks for the input.
     
  7. wiztecy

    wiztecy Active Member

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    #7 wiztecy, Oct 26, 2016
    Last edited: Oct 26, 2016
    You really should only be pulling 32Amps from your 40Amp rated outlet. Electrical code states that you can pull a maximum of 80% of the rated power for that outlet. Are you really sure you read 36amps? Any chance it may have read 32amps? (80% of 40 = 32) I charge my Roadster using the Juicebox off a 50amp rated outlet, the max the Roadster can pull from it is 40amps (80% of 50 = 40)
     
  8. wiztecy

    wiztecy Active Member

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    Right, I forgot you had a Roadster that didn't work with the SR. That sucks :(

    In that case you could set the JuiceBox up with a 50amp plug end (possibly salvage that pigtail off you're UMC as well) and take that along with you on trips, its not as compact as the UMCs but it is portable. The JuiceBox is about the same size as the original Roadster mobile charger, the MC240.
     
  9. Msjulie

    Msjulie Member

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    it's a 50 amp outlet, a JuiceBox that can supply 40 - I can confirm on the car next time though
     
  10. wiztecy

    wiztecy Active Member

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    Ok. So reading what you said below:
    "mine can only supply 40amps and my roadster seems to have decided to pull 36"

    So 50 amp circuit, Roadster connected. You say that from what I can read here is that you can pull 40amps from it which I guess you tested on other vehicles, but for some reason the Roadster is limited at pulling 36 amps? If so did you try to tell the Roadster in the VDS display to pull more amps? Just hit the "+" sign while its charging. The Roadster will remember this based upon GPS coordinates so you don't have to change at every different charge location.
     
  11. Msjulie

    Msjulie Member

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    The JuiceBox I got was rated at 40 - I will try the experiment you say with the + next time - have you done the math to know how much quicker that is 'cause I didn't :)

    This is basically mine, not hard wired but 'portable' and the cable is orange vs black for whatever that means. We got it when we had a leased Fiat 500e which meant a 30amp charger was enough.

    https://www.amazon.com/JuiceBox-Charger-Electric-Vehicle-Charging/dp/B00I4D6SJ2/

    thanks
     
  12. wiztecy

    wiztecy Active Member

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    Nice seeing 277 five star reviews for it on Amazon for the JuiceBox. I'd also give it 5 stars as well.

    Here's the link to Emotorwerks who make JuiceBox. Feel free to call them if you have any questions, they're really great people for sure and happy to help:

    JuiceBox EV Charging Stations

    You can send them your Roadster cable and have them use it on the Juicebox so its complete and ready to go on your Roadster.
     
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  13. nsxpert

    nsxpert Member

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    wiztecy...
    any chance you can post a picture of your modified juicebox setup? Also curious to know how long it took them for the customisation.

    I rely on my ~2 year old Roadster UMC at home so this thread is making me nervous o_O
     
  14. wiztecy

    wiztecy Active Member

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    Here's the link, didn't take them long. I told them to take a week or whatever they needed. I gave them the 70amp Clipper Creek Roadster connector and wire (Bought off Craigslist) which is super thick and that gave them a little issue since it didn't fit as an ordinary cable would through the JuiceBox housing. But they devised a way to make it work and made it happen. With the 40amp UMC end if you cut that and installed it won't give them any issue so the turnaround would be quick.

    EMotorWerks JuiceBox Pro build with the Clipper Creek Roadster cable
     
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