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Is anyone metering their charger's kW usage?

Discussion in 'Model S: Battery & Charging' started by Maximapolak, Jan 12, 2017.

  1. Maximapolak

    Maximapolak Member

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    I'm thinking of installing a meter before the HPWC to measure how many kW the charger is pulling. It would be good to figure out how many kWs are for the car on my bill. Does anyone have one installed? Pros? Cons?
     
  2. traxila

    traxila Member

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    Other early adopters have done this already. Search the site.
     
  3. David99

    David99 Active Member

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    I have done it for a while but then I dropped it. The car keeps track of it and that's good enough for me. The energy reported by the car and the energy needed from the grid is of course not the same. There are losses in the battery and the charger and cables from the power company meter to your car. All things considered you can add aprox 20% to what the car reports.
     
  4. davewill

    davewill Member

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    I do, although it was a bit of an accident. I was originally on a special program that billed separately for EV usage and needed a submeter. When I got solar, I left the program. Rather than remove the extra meter box, I bought a meter from Hialeah Meter and installed it in place of the power company's meter. I'm up to 21MWh of power since it was installed. It's a bit redundant since my Blink EVSE keeps detailed stats I can access online anyway.
     
  5. Naonak

    Naonak Member

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    I have a meter on the line for my car connected to my HWPC. So everything goes through the meter that goes through the car and nothing else... so... do you have a question with regards to that?
     
  6. Maximapolak

    Maximapolak Member

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    Are there pros or cons to doing this? Is it useless?

    I'm going to be wiring my HPWC soon and want to have a game plan.
     
  7. Naonak

    Naonak Member

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    There's not really any pros or cons. If you want that extra data, do it... it's inexpensive and easy to do. But will it help you in the long run? Probably not, unless you keep close tabs on it and notice a huge differential in the amount of power used normally vs a problem state - then it might alert you to a problem... but it's far more likely that the car will alert you before you notice any actual problem with regards to a power delta.

    I just have it because I had an extra one lying around and I am interested to see how much power I use, solely for the cars, over X amount of time.
     
  8. Mach Schnell!

    Mach Schnell! Gearhead, Engineer & P100D(L) Pilot

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    I now have 400 amp main panel with dual meters, feeding 2x 200 amp panels, 1 for main house, other for EV charging only. This allows me to have house on old school "dumb" meter with tiered (not timed) electric usage rate for the house, and "smart" meter (timed) for lowest rate for EV charging only. Very expensive installation but I didn't want the incremental cost of EV charging (>$0.40/kWh at highest tier Vs $0.11/kWh EV charging) and I didn't want to change to timed usage in house. Waiting to see first bill and compare actual energy consumed Vs useful energy charging battery.
     

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  9. andrewket

    andrewket Well-Known Member

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    I've got dual meters, one is for the house+solar doing net metering, the second is on a TOU plan just for the EVs. On top of that I've got two eGuage devices I use for individual circuit monitoring. All three of my EVSEs are being individually monitored.
     
  10. mrElbe

    mrElbe Active Member

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    I installed a meter before the breaker - see here: Charging
    There are cheaper ones on Ebay but I chose the one from EKM Metering.
    No cons. I keep records for all my energy usage in the house and this way I know what the car used.
     
  11. Theshadows

    Theshadows Active Member

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    We are metering ours.
     
  12. Naonak

    Naonak Member

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    That's the one I used. I had a spare one lying around, so decided to install it when I wired up the HPWC. My only regret is that you can't reset those meters, so I have to do mental math every time I look at it, since it had a starting "balance" when I installed it.
     
  13. kash

    kash Member

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    do you guys think the extra money is worth it for metering?
     
  14. davewill

    davewill Member

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    It serves no purpose except your own information, so only you can really answer that.
     
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  15. Maximapolak

    Maximapolak Member

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    I decided to do it to keep track of what it's costing me from home.
     

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  16. Zythryn

    Zythryn MS 70D, MX 90D

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    It all comes down to what the knowledge is worth to you.
    We recently built and installed eGauge so I could monitor the majority of my house's production and consumption. Including both EVSEs.
    The knowledge helps me lower our electric bills.
    I've also become very aware of how much more power our EVs use due to pre-heating:eek:
     
  17. ColdRauv

    ColdRauv Member

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    Yes, there is no other way to determine true prewarming costs than with an inline meter. It is SIGNIFICANT in our state, but I'm worth it!
     
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  18. Gig103

    Gig103 Member

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    I'm wondering what sort of vampire load the charger takes when the car isn't plugged in? I leave my UMC plugged in 24/7 and charge only every other night. I doubt the vampire load, if any, is worth the wear on the plug in and out each night, but I was curious about it.
     
  19. tga

    tga Supporting Member

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    I put the 5-15 adapter on my UMC, and plugged it into a 120V Kill-A-Watt meter. It bounces between 1.1 and 1.2 watts. I would expect similar idle power at 240V.

    Personally, I'd worry more about wear and tear on the outlet than wasting 10kWh/year.
     
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  20. Gig103

    Gig103 Member

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    I agree about wear & tear, it was a curiosity thing. Thanks for posting it :)
     

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