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Wall charger consuming >10KW daily when not in use

It took me about 7 months to identify the culprit of why my electricity bill skyrocketed after I purchased the Model X earlier this year. My home electricity consumption ranged between 300-400KW before the car arrived, it shot up to 900-1300 KW when I used to charge the car 2-3 times a month in my garage. My electricity bill went from $50-75 a month to high $200 range, I felt the promise of electric car was a lie. So last month I solely used superchargers, and my electric consumption went down to 750KW. Something was still not adding up. So I thought hard about all things that had changed in my household, and unplugged the wall charger from the outlet, observed for 2 weeks, and my daily conservation went down to 10-12 KW, getting back to my previous 300-400KW a month range. This is completely mind boggling, and no laws of physics seem to be able to explain it. Anyone had similar observations?
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Comments

  • What "wall charger" are you using (actually these are connectors, not chargers - the actual charger is inside the car). For example, are you using the Tesla Mobile connector plugged into an outlet, or the Tesla HPWC, or some third-party unit with a J1772 connector?

    Tesla's connections take less than 2W while not connected to a car. If it is taking more, something is clearly wrong.
  • I am sorry about the terminology, yes I am using the corded mobile connector which used to plugged into the wall outlet that I got installed with a licensed electrician when I first bought the car. This one: https://shop.tesla.com/product/corded-mobile-connector
    And yes, something is clearly wrong with that piece of equipment that I have :/
  • I think your measurements are wrong. If the mobile connector was consuming that much energy, it would have to be going somewhere. 350-450kWh of energy is a LOT of heat - your mobile connector would be glowing.

    Also, you are confusing kW with kWh.
  • I may be wrong in my terminologies, but the numbers below are from my electric company's website.
    Daily usage without the wall connector: 13-14 kWh
    Daily usage with the wall connector plugged in: 22-25 kWh
    These numbers are in the last month or so when neither the AC nor the heater is running in the house.
  • Something is not adding up here. Let's get some terminology straight first. Your monthly electric bill of "350-450KW" should be stated as 350-450kWh. That would equal 11-15kWh per day or 486-625W of average constant power draw.

    So an extra 450kWh per month would be something using 625W of power constantly. I am going to say that it is impossible for the corded mobile connecter to draw that amount of energy for a month without catching fire or at a minimum being too hot to touch.

    I see your words but there is something else going on.

    What type of outlet are you plugged into?
  • Once had a friend remodel her house with all new energy efficient appliances and her electric bill went up. It was because she took her old refrigerator and put it into her garage that was usually between 80 and 90 degrees in the summertime.
  • Looking at this page (https://www.tesla.com/support/home-charging-installation/mobile-connector), it seems I have the NEMA 14-50 connector on the wall that this licensed contractor installed by doing something on the main board right outside my garage.
  • > @Tesla2018 said:
    > Once had a friend remodel her house with all new energy efficient appliances and her electric bill went up. It was because she took her old refrigerator and put it into her garage that was usually between 80 and 90 degrees in the summertime.

    I hear you, and I do have a refrigerator in my garage as well, bad news is it's been there for the past 5 years. Trust me, I scratched my head for months before nailing down this source. I know this does not make sense, hence I am looking for you guys to share ideas.
  • By the way, I honestly thank you guys for taking the time and helping me troubleshoot. It is either the connector itself, or a combination of the wiring and the connector, either way, when it is unplugged from the wall the electricity consumption stays as it always used to be.
  • So when you unplugged the mobile connector, what it really hot to the touch?
  • Hmm I didn’t check, I will try to plug it back again and see.
  • I agree with the poster that is skeptical that it has anything to do with the mobile cord, as dissipating 500W over its surface area would be quite noticeable.

    There's something else going on in your home. Electric heat or forced air plus outside temperature changes?
  • Another fairly quick test is to have the MC powered, but not connected to the car.

    Look at your outside electric meter. Newer ones have a digital display that rotates through different values. It should show the current power draw in watts. Note that level. Remove the MC from the NEMA 15-50. Again check the power at the meter. I'd expect it to drop by about 2 W or so. It might not even register as any difference.

    Now, trip the breakers where the MC is connected and check the meter once more. Did it drop quite a bit? If so it indicates something else is on the same circuit and is drawing power.

    Hear's one guess at what may be going on. I suspect the circuit for the NEMA 14-50 is shared with some other appliance, such as other outlets in the garage and something else is using that power. You may need to look around and see if something is no longer working when the breaker is off.
  • not an owner yet.

    you said something was done "on the main board right outside my garage". i don't know your location. i'm in NJ (USA) not an expert by any means, but i've not personally seen a breaker panel outside of a home (save for transfer switches). also, is it possible that your meter was switched for some reason? (rate change/class etc)

    that said, it might be prudent to have a different electrician take a look, maybe the power company?

    i think it would be a stretch that someone was stealing your power, but it is not unheard of. good luck, ron
  • one other thing. i am billed by power co on actual or estimated basis. meter is not read every month. could this be an impact for you? ron
  • > @KodeSharp said:
    > Hmm I didn’t check, I will try to plug it back again and see.

    It would have been memorable if it was hot when you unplugged it.
  • I live in Irvine, CA. The home was built in 2006 and circuit breakers are located outside for most properties around here. Also the electric company website (SoCal Edison) shows energy usage on their website as fine as an hourly basis (with one day delay). So it is definitely not a meter reading issue. Weather is pretty much 70 degrees year round here, and I have not had either the heater or the AC kicked on in the last 2 weeks or so.

    For those who has the time to spend and the trust that I have no reason to hack your computer with these links, here are some screen shots from my electric company website:

    1. 2020 Monthly Usage (I got the Tesla in May): https://www.dropbox.com/s/m813c7d0m7qeyhk/Monthly%20Usage%202020.png?dl=0

    2. 2020 December daily usage (with wall connector plugged in, I did not charge the car during this month at all, and we were out of town on Dec 19 and 20): https://www.dropbox.com/s/przwvcs4n9uvaki/Daily%20Usage%20December%202020.png?dl=0

    3. 2021 January usage (we were out of town on 13 and 14, came back on 15th and charged the car overnight, and unplugged the wall connector on Jan 17): https://www.dropbox.com/s/qdcqcx6o9lr6ojq/Daily%20Usage%20January%202021.png?dl=0
  • Some good checks have been suggested by knowledgable posters, but the fact remains that the only change the OP states he's making is to have the mobile connector plugged in or not plugged in. Unless he's leaving something out, or forgetting something else, that means the mobile connector is playing a role somehow. There's something else on that circuit that's somehow energized / de-energized when the mobile connector is plugged in / not plugged in?

    It sure would be nice to know what was done "on the main board right outside my garage".
  • Yodrak - you summarized my situation very well. The electrician told me he merged two phases of 110v on the main wall unit to create a 220v outlet in the garage, that’s as far I can technically tell you about what was done.
  • I guess it never rains :)

    If it were me I would get someone in asap just in case something is happening that you can't detect.

    I like to err on precaution side.
  • Hey I have a test...

    Get out the 5-15 Tesla pigtail and use that and plug it into a 120V outlet and see what that does. It should tldo the EXACT same thing.
  • > @rcsjr said:
    > I guess it never rains :)
    >
    > If it were me I would get someone in asap just in case something is happening that you can't detect.
    >
    > I like to err on precaution side.

    Indeed, now that I do not have the connector plugged in, I already feel a bit safer. But do want to go to the root of this. Oh, it’s raining in Orange County this entire week lol
  • > @derotam said:
    > Hey I have a test...
    >
    > Get out the 5-15 Tesla pigtail and use that and plug it into a 120V outlet and see what that does. It should tldo the EXACT same thing.

    Great idea, I will try that. But may be connector behaves differently when connected to 110v vs. 220v, but it’s worth a try anyway.
  • > @KodeSharp said:
    > Yodrak - you summarized my situation very well. The electrician told me he merged two phases of 110v on the main wall unit to create a 220v outlet in the garage, that’s as far I can technically tell you about what was done.

    Again, not an expert, but you don't actually "merge". Two 110 legs are picked up and brought to the outlet individually. Plug is 2 line, 1 neutral and a ground. Expect that's what you mean cause if anything got merged it would be an issue.
  • > @KodeSharp said:
    > > @rcsjr said:
    > > I guess it never rains :)
    > >
    > > If it were me I would get someone in asap just in case something is happening that you can't detect.
    > >
    > > I like to err on precaution side.
    >
    > Indeed, now that I do not have the connector plugged in, I already feel a bit safer. But do want to go to the root of this. Oh, it’s raining in Orange County this entire week lol

    I'm in Irvine, too, and I don't believe your consumption is because of the mobile connector. I would get that electrician back out. There is no way the UMC could possibly dissipate that amount of energy by itself.
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