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Extra UMC vs. HPWC?

Discussion in 'Model S' started by HeartDocMD, Jul 12, 2015.

  1. HeartDocMD

    HeartDocMD Member

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    Considering how best to do my install for charging. It seems to me that if you are going to get a spare UMC (with the idea of leaving one plugged in at the house and keeping one in the car), it makes more sence to just gets the HPWC?

    For only $100 more you get a cooler looking installation that is hard wired into the house with a longer cord--even if you don't plan to get dual chargers or set it up with 80 amps--

    Anything I'm missing here?
     
  2. ecarfan

    ecarfan Well-Known Member

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    I agree. And I bought my HPWC when it was far more expensive than it is now. The price is now so low that it seems like the obvious choice to me for home charging even if you are only going to use it to charge at 40A and not 80A.
     
  3. russman

    russman Member

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    You have to account if there is additional electrical work for the HPWC vs at 14-50.
     
  4. GSP

    GSP Member

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    Not if you set it up for the same breaker size. The HPWC can be used with breakers as low as 20 A (16 A charge rate). I would go with the HPWC instead of a second UMC regardless of what size circuit you have installed.

    GSP
     
  5. HeartDocMD

    HeartDocMD Member

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    Thanks, appreciate the feedback.

    Now I can go back to worrying about more important things like whether the premium package is actually worth $3000 for the power lift gate (useful but $3000?) and some bits of chrome, LED, and leather accents (not very useful), and the related question as to whether it is OK to have grey interior with the white headliner:)
     
  6. TES-E

    TES-E Member

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    HPWC is the way to go. UMC stays in the car for emergencies. Aside from the $100 additional cost, for the same size feed the cost should be no different.
     
  7. Nashville P85D

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    Nashville, TN
    I just went through exactly the same thing - I ended up simply installing a NEMA 14-50 and forgoing the 'cleaner' install of the HPWC. It came down to a few things:

    1. No benefit to charging due to lack of dual chargers and no need to add dual chargers for my use
    2. The electrician who did the install would have charged approx. $800 more for this install. I have a three car garage and this plug was going on the wall furthest from the main interior of the home.
    3. I decided I really didn't need an extra UMC to carry around in the car - which was part of my justification for the HPWC.

    Overall I saved ~$1500 between the install and passing on the HPWC (or) extra UMC.
     
  8. TexasEV

    TexasEV Active Member

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    May I ask why you want to keep a UMC in the car? For most people this isn't necessary give the range of the car. At first glance for people who are new to Tesla it may seem like a sensible thing to do if you're concerned about unforeseen emergencies, but it's really like carrying a can of gas with you when you leave the house with a full tank and you're just going to drive around town. If you're going out of town and there is any possibility whatsoever that you may need to plug into an outlet, even as a backup to other plans, then take it with you. Otherwise I'd just leave it hanging on the wall in your garage.
     
  9. HeartDocMD

    HeartDocMD Member

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    All completely logical, but of course that line of sensible thinking would ruin my internal self justification for getting the HPWC:)

    Also, will be outdoor installation (on side of house), and the cleaner look of HPWC is likely to have higher WAF, which is the ultimate justification for anything.
     
  10. kuttakamina

    kuttakamina Member

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    Few things to consider,

    1. HPWC will cost more to install.
    2. HPWC doesn't come with the car. UMC comes with the car. Yes rather than buying a second UMC (spare), it may make sense to get the HPWC. It also has a longer cord (5 feet).
    3. NEMA 14-50 can be repurposed to charge a different kind of EV in the future. HPWC is Tesla specific.

    I did not get the HPWC, but then I didn't get a second UMC either. I keep the J1722 plug in the car for emergencies that will most like never happen. The range of the car is enough that it gives you all the opportunity to plan.

    Oh and I got the prem. interior :). Saving on premium interior is like .. saving on the box of a rolex. You gotta do it right IMO. Don't skimp, get what you want. You'll save a few bucks now, but the bitterness of missing out on something will remain through the lifetime of the car. :)
     
  11. smsprague

    smsprague Member

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    I got the HPWC and attached a plug to it for power. It is set to 40 Amps. This allows me to use my UMC as a back up. I just keep the UMC in the car.
     
  12. TLee

    TLee Member

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    Location:
    Trafalgar, IN 46181
    Anyone concerned about cable temps?

    I noticed that the UMC cable on my 50 amp circuit (limited to 40 amps charging) got quite hot during charging. So, I reduced my charge rate to 30 amps (still plenty to re-up the battery overnight) and the cable was only slightly warm then. Being a chemical engineer, I suspect that the hot temp will 'age' the cable a lot more over time, and will reduce its life. Has anyone else made this observation?
     
  13. !S4

    !S4 Member

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    My DS talked me out of getting a spare UMC. He said just leave the UMC at home unless you're going on a trip and try it for 30 days. So, that's what I'm doing for now and it makes lots of sense to me.
     
  14. Spacebird

    Spacebird Member

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    I just got my 85D on Wednesday. I'd installed 14-50s in my driveway in MA and my garage in VT, so I keep the UMC in the car. I took my first drive up for the weekend and everything charged up fine.
     
  15. mknox

    mknox Well-Known Member

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    I had made my decision to go with a HPWC over a second UMC. When I mentioned this as I picked my new HPWC up at the Service Center a week or so ago, I was told that I couldn't have got a second UMC even if I wanted it. They are no longer being offered for sale in Canada.
     
  16. smilepak

    smilepak Member

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    Weird why it is no longer offer for sale.
    I originally got the hpwc, but returned it due to not having dual charger and reading about so many issues ppl having. I'll wait a year to see if they revise it
     
  17. mattmass

    mattmass Member

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    Hrm, interesting. One the one hand, didn't Canadian electrical code change such that EVSE equipment had to be hard-wired? Perhaps this is why?

    On the other hand, maybe this is evidence that the speculated new UMC design is close. Lines up with model X release fairly well...
     
  18. mknox

    mknox Well-Known Member

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    No changes to any codes that would have driven this. Other EVs still come with portable charging cords and products like this are still for sale. I am suspicious that a re-design is coming. A lot of folks have had UMC problems, myself included, and the adapters for the current UMC seem to be gradually disappearing from the Tesla store too.
     
  19. Pilot_51

    Pilot_51 Member

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    I'm in the middle of this situation now. I initially had a 14-50 installed a year before I got my car. I bought the HPWC a couple weeks ago and am waiting to have it installed, tentatively Saturday morning.

    My justification:
    • Keep the UMC in the car for convenience or emergencies, however unlikely they are.
    • A more permanent and capable connector that doesn't get nearly as hot at 40A and I don't need to worry about wearing out.
    • Future-proofing in case I decide to upgrade to dual-chargers or a future Tesla car (perhaps Model 3) or if other owners want to utilize it (I'm on PlugShare).
    • An excuse to stop procrastinating and get my car moved over to the EV meter instead of the house meter. I wasn't sure if DTE would allow the 14-50 on the EV meter since it could be used for other things, but they would have no issue with the HPWC.
    • Allows me to show off everything instead of just the bag with 5-15 and J1772 adapters. I also bought the 10-30 and 5-20 adapters with the HPWC.
    • All that for only $100 more, plus whatever extra installation costs.

    I'm still not sure how I want it installed. Ideally, it would be on a separate 80/100A circuit from the 14-50, but that depends on cost. The cheapest option would certainly be to replace the 14-50 and use the existing wiring at 40/50A. The electrician is scheduled to take a look and give me estimates/quotes on Wednesday evening.
     
  20. vdiv

    vdiv Chief Grump

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    I live in a condo where I cannot install an HPWC so I rely entirely on the UMC. For redundancy and for convenience I got a second one that I keep at home for overnight charging while the original one is stowed in the car.
     

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