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Two many EV's in one home?

Discussion in 'Model S: Battery & Charging' started by NoMoGas, Sep 15, 2013.

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  1. NoMoGas

    NoMoGas Member

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    If Elon's dream of an electric world comes to fruition I have to believe this issue will become more common. By the next year I will have a MS, MX and Volt in my garage. My current idea is to use the charge scheduling to "rotate" charge times at night with HPWC's for the Tesla's... but is there a better way? I suck at math but it seems at some point we could max out the service to the house.

    Your thoughts? Anyone else have similar issues?
     
  2. dsm363

    dsm363 Roadster + Sig Model S

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    How many amps do you have going to the garage? If you have them all plugged in at the same time, stagger the start times for charging or maybe just lower the amps to something low enough where it will be full by morning but not overwhelm your system. Maybe start the Model S at 4AM to 40A, start the Model X at 1AM at 40A and start the Volt on plug-in when you get home or maybe MN.
     
  3. NoMoGas

    NoMoGas Member

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    In my case I'm a bit lucky in that the main 200 AMP service comes in on the outside of the garage wall so I can come right off the back of the main panel into the garage.

    This issue with the Chevy Volt is that it has a 12 hour charge time (really GM?) so I need to install 2 HPWC'S and a Voltec J1772 to cut down the charge time or risk "overlapping" and maxing out my service. I should be able to run 2 HPWC's at 80 Amps each and still have room to spare. (in theory)

    I should add this will be sub-metered LADWP TOU service ... assuming I can sub 200 Amps from the main panel.
     
  4. Zythryn

    Zythryn MS 70D, MX 90D

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    How much do you drive?

    I would suggest simply taking 40 amps for each Tesla and let the Volt chug along on a 110 plug (that is how we charged the Volt).
    No worries about overlap, all cars could charge from empty to full and it is the simplest and cheapest option.
     
  5. dsm363

    dsm363 Roadster + Sig Model S

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    Agree. Two HPWCs is a lot. Maybe have one HPWC, one NEMA 14-50 and maybe even a ClipperCreek LCS-25 (240V 20A) for the Volt. Can charge at 40A on the HPWC and ramp up more if needed.
     
  6. Jason S

    Jason S Model S Sig Perf (P85)

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    How many amps would you likely need in one overnight? Are all three cars going to be parked below 20% of charge? (Well, the Volt prolly will be but that thing apparently doesn't use many amps per hour; it only goes 30 miles on a charge, how big could its battery be?)

    Once you know your total draw, the rest of the math works itself out.
     
  7. andrewket

    andrewket 2014 S P85DL, 2016 X P90DL (soon 100)

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    I'll be in the same boat. I have the MS and the volt now. MX next year. In using an LCS25 for the volt. Our driving pattern has us charging twice a day. My plan is exactly the same as yours: rotate the HPWC between the two Teslas. My TOU super off peak period is only 5 hours long. I only have 125A going into the garage right now.
     
  8. NoMoGas

    NoMoGas Member

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    The Volt is a complete dog once we get spoiled with the MS. :biggrin: Ive seen a couple of good ideas here to consider. Namely getting just one HPWC. The trick is moving all the charging to night time.
     
  9. MarkR

    MarkR Member

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    I hope some residential developers are listening. Having adequate circuitry in garages is going to be an increasingly important issue as the popularity of EVs increases.
     
  10. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    Even with TOU, I shudder at the thought of how big your electricity bill might get! Are there rate tiers even with a TOU plan in your area? You may run into higher tiers easily with all this and the price advantage over gasoline may diminish fast.

    Sorry, a bit OT.
     
  11. dsm363

    dsm363 Roadster + Sig Model S

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    Would you really need to rotate the HPWC? Put the car that drives the least on the NEMA 14-50 at 40A and the other on the HPWC Tesla. On the probably rare instance the other car drove more you could always rotate then. Even at 40A you should be able to add over 120 miles of range from midnight to 6AM. If you think both cars will drive more than 150 miles or so a day and won't have more than 6 hours of charging each night then maybe two HPWCs would be a good idea.
     
  12. AlisoJames

    AlisoJames Member

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    #12 AlisoJames, Sep 15, 2013
    Last edited: Sep 15, 2013
    We are currently charging our Model S and a Leaf using the J1772 unit we got 2 1/2 years ago when we got the Leaf. Most of our driving is with the MS and I have not had any problem with charging overnight. The Leaf probably only charges a couple of times a week. We are moving ahead with installing solar panels on our roof which will cover about 75% of our current consumption. I would recommend solar to anyone with multiple EV's so you are not at the mercy of the utility. We are opting for a prepaid 20 year lease that gets us maintenance coverage (it is through Solar City) and locks in our cost at $.09.
     
  13. Puyallup Bill

    Puyallup Bill Member

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    Not in the same league as the OP, but like AlisoJames above, I charge both the Tesla and the LEAF with a very limited service in my rented apartment. Both get charged with 240 volts, 12 Amps, but not at the same time. For "rush" jobs, I can plug the Tesla into the electric stove outlet.

    Lots of good suggestions - where there is a will, there is usually a way.
     
  14. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    For those who are considering 2 future EV's, I've been suggesting a 150A feeder to a garage subpanel for charging, which feeds a NEMA 14-50 and a high-current L2 charger (HPWC). This is what we'll have once the Model X arrives.
     
  15. earlyretirement

    earlyretirement Model X 90D

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    Funny, I was thinking about this same thing today. I do plan on also getting a Model X next year. I went with the dedicated 2nd meter and TOU EV pricing. I plan on just alternating HPWC between the Model S and the X as we don't drive too many miles each day so I figure I can just take turns charging it one day to the next. At a charge rate of 60 miles per hour with the dual chargers that is fast enough.

    I'm also thinking about adding solar and doing some due diligence on that.
     
  16. kendallpb

    kendallpb Model S: P 8061

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    When will your cars typically get home and how long will the longest to charge take? At 80 amps, 5 hours. Will both cars typically be home for 5 hours each? If so, and you have two HPWCs, then schedule one to start 5 hours before it leaves, and the other for 5 hours before that. That way you've left the most time possible and won't have any overlap. (To be on the safe side, you could schedule them 6 hours apart, in case one comes home late.) But let's face it, you won't really need to do that since you're not going to be charging from empty every time. But also, you could use charge limiting on the cars, mixed with scheduling, to further protect yourself from overlap if it's an issue.

    But the HPWC + 40-amp outlet folks recommend sounds good.

    Then there's my plan: I hope we replace my other half's SUV with a Tesla, one day, if it lasts that long. With two Teslas . . . well, we keep quite different hours (and always have--no matter what schedule we're on, they're never direct overlaps). So I'll move the cable from one to the other. "Every night," I hear you all gasp? Yes--not a big deal, what, it takes seconds to do this. So if you decide on one HPWC but want the faster charging, you could plug in whoever-leaves-earliest first, then before going to bed, swap cables. You don't mention commute times, but maybe this could work.
     
  17. EarlyAdopter

    EarlyAdopter Active Member

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    How many miles do you drive each car daily? If any are less than 40 miles, plug them in to 120V 15A. Save the higher voltage and amperage for the high mileage ones, or the rare top off if it's normally none of them. People often discount the day-to-day utility of 120V charging.

    Ideally you'd plug all three into 120V sockets and not have to worry about load. Come morning you'd have 40 miles back on all three cars. Once a week top one car off with 240V if you need it.
     
  18. dsm363

    dsm363 Roadster + Sig Model S

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    Agreed. Unless both drivers are very high mileage drivers with very little time at home overnight an HPWC plus 14-50 outlet/UMC should work well. You'll probably even find you dial the HPWC back.
     
  19. widodh

    widodh Model S R231 EU

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    I think you should be looking at a Smart Grid.

    In Europe the Austrian manufacture Keba has such a solution. If you purchase 3 charging stations from them you can buy a "smart controller" which controls the total amount those three stations are pulling.

    It will make sure the three stations combined never go over X Amps prevent you from overloading your main breakers. If one EV stops pulling power that becomes available to the other one.

    This won't work with a NEMA 14-50 socket nor with the Tesla HPWC since it requires J1772 with additional logic inside the charging station.

    Their charging stations have Type 2 sockets (Europe) or fixed Type 1 (US) cables.

    Some links:
    * Features - KeContact P20 - Products - KeMove - Electromobility - Energy automation - KEBA AG - Automation by innovation.
    * KeContact M10 - Products - KeMove - Electromobility - Energy automation - KEBA AG - Automation by innovation.
     
  20. Bonlaw

    Bonlaw Member

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    #20 Bonlaw, Sep 17, 2013
    Last edited: Sep 17, 2013
    Can there ever be two-too many? We have the Volt charger J 1772 which we used for the S initially, then added a NEMA 14-50. Now we can charge both at same time, although rarely need to because we drive the S 90% of the time, the Prius on weekends for golf ( to transport our electric walking golf carts - maybe should have put them in picture too ) and the Volt only to crowded parking lots like Costco. Volt going back as soon as lease is up. Loved it until we got the S.


    https://picasaweb.google.com/bonnierosenlaw/Garage
     

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