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questions re charge

Discussion in 'Model S' started by nleggatt, Dec 7, 2011.

  1. nleggatt

    nleggatt Member

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    I can't post a new topic, so I'll ask here:

    1) how long to charge a 160 mile pack on a standard 120volt outlet
    2) if you get stuck somewhere, how do you get jumped (or can you)
    3) what about a 220 volt? (does is matter amps)?

    wahoo 244 res holder in Canada
     
  2. ckessel

    ckessel Active Member

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    #2 ckessel, Dec 7, 2011
    Last edited: Dec 7, 2011
    You should be able to find the answers at:

    Universal Mobile Connector | Charging Solutions | Tesla Motors
    Spare Mobile Connector | Charging Solutions | Tesla Motors

    There is no "jumping" an EV though. ICE can jump because you just need energy long enough to turn the starter and start the combustion process and the generator takes over from there. For an EV, you either have power or you don't and if you don't then you need to charge. Most insurance has a towing add-on for really cheap, like $5 a year. I just have my car towed anytime my car dies or a tire goes flat, which is maybe once every 3 or 4 years.
     
  3. eledille

    eledille TMS 85 owner :)

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    #3 eledille, Dec 7, 2011
    Last edited: Dec 7, 2011
    You usually don't get stuck, because the energy meter is extremely precise. An ordinary fuel gauge only gives a rough indication.

    There is almost a way to "jump" an EV - you get someone to tow you while regenerating. I've done it, I got 30 km of range in about 15 minutes. Just be careful so you don't fry his clutch... I wouldn't recommend this as a standard procedure :)

    I did it because my charger was broken and I had to get some power into the battery before it died completely.
     
  4. richkae

    richkae VIN587

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    AAA announced that they will have a mobile recharge service. It is fairly simple, either a battery or a generator on a truck and the truck arrives and plugs into your car, giving you a little bit of juice. Instead of a dirty generator they could easily have a small ( Volt or Leaf sized ) battery and a big inverter ( a pair of 8kW inverters ) and deliver ~20 miles of range with a 20 minute charge. Then you drive off to the nearest place you can plug in and charge.
    Or instead of the inverters, they could directly deliver DC with a level 3 charger.
     
  5. nleggatt

    nleggatt Member

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    @eledille Towing is an interesting idea. Could I get a tow truck to tow me for 15 minutes, have the car in a regen charge mode and then drive the rest of the way home? I wonder if you could toss a solar panel or two in the trunk or front space, and use it to charge while at the beach, or stuck, or whatever, read a book for a couple of hours while it charges. Anyways thanks for the responses.
     
  6. NigelM

    NigelM Recovering Member

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    This was AAA back in the summer:

    attachment.php?attachmentid=3583&d=1323304551.jpg
    evmobilecharging.jpg
     
  7. user497

    user497 Member

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    I charge exclusively with a 120V and I usually count on 5 miles per hour. When I plug it over night I usually plug it in for 10-12 hours and get 50-60 miles. I usually drive 20 miles per day so I can easily fully recharge after 2-3 days of not plugging it in.
     
  8. Andrew Wolfe

    Andrew Wolfe Roadster 472 - S 440

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    #8 Andrew Wolfe, Dec 7, 2011
    Last edited: Dec 7, 2011
    Somewhere around 5-6 miles of charge per hour is right using 120V at 13A (typical 120V draw for an EV). Tesla will support multiple kinds of 220/240V connections from 20A to 90A. This will provide anywhere from about 15 miles per hour of charge to more than 70. You would need the dual charger option on your car to get more than 35 or so. Most people will use 30 or 40A chargers and be in the 24-32 miles per hour of charge range.

    If you want to charge a pack to 100% - add an hour or two since the charge slows as it nears full. Many people will only charge to 80% to preserve battery life.

    BTW - this means that the 300mi pack (84KWh?) will take 60-65 hours to fully charge on 120V.
     
  9. robaross

    robaross P4550

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    Is there any cost difference charging for 6 hours at 120v/13amps (30 miles of range) or 1 hour at 220v/40amps (also 30 miles of range)?
     
  10. VolkerP

    VolkerP EU Model S P-37

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    upfront cost for a 40 amp socket are higher. But I assume your question is about running cost?
    In that case there are some roadster owner studies into that, e.g. Mark's extensive study. Summary: higher charging currents means less energy lost in A/C to cool the pack while charging. This is an effect in hot climates.

     
  11. strider

    strider Active Member

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    To expand on VolkerP's comments... The car needs a minimum amount of power to monitor the charging, run the cooling, etc. So at low charge rates, a higher percentage of the electricity is "lost" due to charging and cooling overhead and as you move up the current scale a lower percentage is lost. Note that it's not a huge amount but you asked the question. So technically, it would cost you more to charge at 120v/13 than 240v/40.

    Assuming you're in the US and you have a garage, it's pretty cheap to have a NEMA 14-50 outlet installed. Don't tell the electrician it's for an electric car - the price may triple. Just call up an electrician and say you need a second clothes dryer and need a 14-50 run. Shouldn't cost much at all. My Dad and I ran 2 of these circuits in a couple hours (breaker box was in the garage and the ceiling was open so it was easy to run up the wall and across the ceiling).
     
  12. Dan5

    Dan5 Member

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    As per an email with the Tesla rep, he said I needed a 50 A 220 V breaker able to pull 40 A of constant draw to charge the car.
    Assuming no losses for the 220 V, 0.220*40 = 8.8 kW

    300 mile battery
    85 kWhr/8.8 Kw= 9.65 hrs, say 10 hrs after factoring in the losses
    230 battery
    65/8.8 = 7.38 hrs, say 8 hrs factoring in losses
    160 battery
    42/8.8= 4.77 hrs, say 5 hrs factoring in losses

    To get the 120 V, it should take between 4.5 and 5.6 times longer (depending on your draw)

    That is a pretty cool idea- towing to let the regen kick it
     
  13. strider

    strider Active Member

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    Yes, I believe there is a 20% drop at each step. For instance, in my last place I was using a NEMA 14-30 plug (240V/30A) I had 40A breakers and the car would charge at 24A. So with a 14-50 plug you'd have 60A breakers and the car would pull 40A (at least this is what I installed).
     
  14. Andrew Wolfe

    Andrew Wolfe Roadster 472 - S 440

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    Electricity cost? Not much. Sometimes the cooling, etc runs while charging so a long charge time might be a little less efficient.
     
  15. user497

    user497 Member

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    Back when that idea first came up, I suggest that rest stops on highways could have machines that cars drive up to and that simply spin the tires so the regen kicks in and quickly recharges the battery. I acknowledged that this would be super-efficient but it seemed at the time to be much faster than some of the quick charge ideas at the time. I was willing to trade inefficiency for time and for simplicity of the solution but some people have said that this wouldn't be great for the battery as well. I'd love to have more discussion on this topic as I thought then (and I do now) that this could be a simple way to extend mileage on road trips without requiring a ton of new expensive technologies for a few years until quick chargers come out and battery technology improves.
     
  16. ChadS

    ChadS Petroleum is for sissies

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    The 20% drop is only needed between the rated capacity of the circuit and a constant load (and this is only in the US; Europe rates what you can pull). So a 50A circuit can (and really should, to protect the wiring) have a 50A breaker; you just want to set your car to 40A because it is a constant draw.
     
  17. Robert.Boston

    Robert.Boston Model S VIN P01536

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    This is a very clever idea. A bit inefficient, true, but it guarantees compatibility with all technologies forever (provided that we don't change the width of cars' wheels, which seems like a pretty safe assumption).
     
  18. ckessel

    ckessel Active Member

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    Seems weird to me to spend electricity to power a machine to spin wheels to put electricity in a battery. Why introduce a middle man..er..machine?
     
  19. SByer

    SByer '08 #383

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    Or that your brother parks his RV in the driveway sometimes. #^$% EV profiteering!

    Note that a 'second dryer' or whatever may still prompt the electrician to have to run another circuit off of a new breaker, or worse, a new panel or house panel (because the circuits are full). Which is really sad, because the times I charge at home is exactly when the rest of the house is mostly asleep.

    (I just used the dryer circuit and I never charge it at the same time as we're dr... oh, wait, I have a gas dryer because it's cheaper to run.)
     
  20. AnOutsider

    AnOutsider S532 # XS27

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    Compatibility is the reasoning.
     

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