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110v charging and extension cord

Discussion in 'Roadster' started by Jackyche, Feb 25, 2013.

  1. Jackyche

    Jackyche Member

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    While charging at my parents condo garage, this is what I experienced.

    I had to use extension cord, 12 gauge, on advise of others in another thread.

    I would sometimes get a "extension cord detected" warning on my 1.5 - however, the charging would continue. This of course, worries me. So playing around with it, I found that if I just wiggle the connection between the extension cord and charging cable, I would hear a clicking sound, the ready light would go off for a second, but come back on. The 110 socket in the garage doesn't appear to be GFCI as it doesn't have a reset switch on the plate. And if I remember correct, a 'double GFCI' situation would trigger a GFCI fault code not a "extension cord detected" fault.

    And if it is a double GFCI issue, where's that thread with the 'hack' to solve it. I can't find it.

    Thanks.
     
  2. strider

    strider Active Member

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    How long was the extension cord? 12g should be fine if it isn't too long. What amperage were you trying to use? The Roadster has 2 settings for if you're plugged into a 5-20 or 5-15 outlet. Maybe you were trying to charge for a 5-20 and only had a 5-15. Finally, if the outlet started out with low voltage (poor wiring or other devices on the circuit like a garage fridge or something) then even with a small amount of voltage drop through the cord it wouldn't charge.

    Here's the thread on replacing the GFCI end: GFCI Trip on Plug in (spare connector))
     
  3. rolosrevenge

    rolosrevenge Dr. EVS

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    If your extra worried, you could dial down the amperage to 12 from 15, or get a 10 gauge cord.
     
  4. Jackyche

    Jackyche Member

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    Its a 50-feet extension cable. I've never tried dialing down the amperage, but the VDS says 110v-15amps. On a normal socket, isn't it usually 15amps and then really 12amps continuous? So dialing it down to 12 amps would be like actually 10 amps of continuous? Wouldn't that take like forever to charge?

    Its just weird that it continues to charge just fine, just has one of those warning screens on VDS, press screen to dismiss type of deals.

     
  5. rolosrevenge

    rolosrevenge Dr. EVS

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    I think it warns you for liability reasons, in case the cord is too small, overheats, and catches on fire, Tesla can say that they warned you and it's your own fault. I observed this behavior when I would do my voltage testing. After I dropped the voltage a certain amount, it would complain that there was an extension cord. On the normal sockets, 15 A should be the continuous. That's what I measured with my EV testing at least. So if you dial it down to 12, you'll be getting 12 A.
     
  6. djp

    djp Roadster 2.0 VIN939

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    I think this is your problem. You're trying to draw 15A off a 15A circuit which is only rated for 12A continuous. The 15A setting should only be used with a 20A circuit (not sure why Tesla made it the default). If you dial back to 12A you should be fine.
     
    • Informative x 1
  7. cor

    cor Member

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    Location:
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    12 gauge extension cord should be OK but check.

    While I do not have a Tesla (yet), I have another EV that I charge through a 100 ft 12 gauge extension cord. Voltage drop in that cord is typically less than 5V, but I have had experience in another building where the outlet was very far from the breaker panel and the wiring to the outlet was worse than a crappy extension cord, because the outlet dropped from 120V to 105V (!) when I tried pulling 15A.
    So, measure the voltage at the outlet before and while you are charging if you want to know if the outlet is already marginal.

    However, in your case it sounds like the contacts in the socket on your extension cord might not be OK, seeing your remark about hearing a clicking sound when you wiggle the charging cord plug in the socket of the extension cord.

    One of the best detectors of problems is heat. If the cord gets a little warm during charging that is normal when pulling large current, but any place that it gets hot that is a clear indicator of loss and a bad contact. So it is good to occasionally "feel" for problems, especially at any interconnect (plug in the wall, charger plug in socket of extension cord, even the charging cable to Tesla connection.

    Your problem can easily be explained if the voltage at the condo outlet is marginal due to too long wiring from the breaker to that outlet, so I suggest to use that extension cord to charge in a different location and also wiggle the plugs to see if you can reproduce the problem in the cord. You can also try using a different extension cord in the same condo outlet to check if the problem is your cord (so you can ask for warranty replacement or attach a new socket) or in the condo wiring.

    BTW, if you are near SF South Bay then you can borrow my known-good 100ft 12 gauge cord.

    Success,
     
  8. strider

    strider Active Member

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    Yes. Outlets are rated at 80% load continuous. So a NEMA 5-15 is only rated for 12A continuous, a 5-20 can to 16A continuous. You should dial it down and try it.
     
  9. Jackyche

    Jackyche Member

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    Spoke to tesla service center today. Apparently the clicking sound means its defective. Cord only has 2 yr warranty.

    But, they do some sort of unofficial repair in it for $50.
     
  10. wycolo

    wycolo Active Member

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    Go to Harbor Freight and buy 10 gauge cables:

    25 foot = $30-US

    100 foot = $100-US
    --
     
    • Like x 1
  11. 5YJSA

    5YJSA Member

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    FWIW, I was trying to decide if I should try charging from an outdoor 120v outlet in Canada with an extension cord.

    I bought a Mastercraft 50' 12 gauge extension cord from Canadian Tire (on sale for $33) and it worked fine. I get 215 v or 216 v from it at 12 amps. I have no idea how many volts I would get straight from the outlet, but the 25' extension cord (which I bought before I found out it was too short to reach my car) gave me only 216 v, so doubling the length seems to have cost me 1 volt maximum.

    The cord does not even get warm, nor does my Model S recognize a low enough voltage to realize I'm using an extension cord.

    I was thinking of buying a 10 gauge 50' cord from Home Depot, but I clearly will only get a few more watts out of it (i.e. the amps from my plug will still only be 12, so even if I get a few more volts, it won't make much difference in charging on a 120v outlet) so I didn't bother because the 10 gauge 50' cord is $100.
     
  12. hcsharp

    hcsharp Active Member

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    This is a Roadster thread but I think the answer to your question is the same. I'm a little confused at how you got 215 or 216v from a 120v outlet. Did you actually wire a 240v outlet and modify the plug on your extension cord to work with it?

    Whether a Roadster or Model S, the car will use considerably more energy to charge the same number of miles at 120v vs 240v. In other words the charging system is not very efficient at 120v. The extension cord will make it worse due to the voltage drop but that will be minor compared to the charger inefficiency.

    Extension cords introduce problems even at 12 gauge which is why Tesla doesn't recommend them. I think you'll find living in Toronto that 120v won't work too well in the winter either. The extension cord on 120v might be a temporary solution until you can install a real 240v higher amperage supply. Oh, and BTW you'll get much better advice posting to the Model S charging thread.
     
  13. 5YJSA

    5YJSA Member

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    Lol. That was a typo. I meant to type 115 and 116 volts. ;-)

    But you're right. I will invest in a 240v charging solution. I'm just deciding whether to upgrade the electrical service to 200 amps because I have the high amperage charger option in my S.
     
  14. hcsharp

    hcsharp Active Member

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    The 200A upgrade will eventually pay for itself with energy savings. 240v charging at higher amps is far more efficient than 120v.
     
  15. 5YJSA

    5YJSA Member

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    I'm skeptical about the cost savings ever being worth it for me because I live in Toronto, and the government here, in a desperate bid to gain popularity, dropped our electric rates, which were already low. The overnight rate here is now 6.5 cents (Canadian!) / kWh.

    I know 240v charging is more efficient because Tesla previously had a charge cost calculator on their web site (which is sadly gone now) that showed the drop in cost from 120v to 240v charging.

    But at $0.065/kWh, if it's twice as efficient, I will save about $0.0325/kWh. I drive 20 km round trip to work about 20 times a month. That's not even one full charge on my Model S 75D (which actually has a usable battery capacity of only 72.4 kWh). Factor in some other local driving and some vampire losses to parking in the cold, let's say I will completely charge and discharge twice a month.

    72.4 kWh * 2 * $0.0325/kWh = $4.71 savings per month (again, Canadian).

    It will cost ~CAD$2,300 to buy and install the wall charger (WITHOUT upgrading my house's service to 200 amps).

    So... $2,300 / $4.71 = ~489 months = ~40.7 years to pay for the cost of the installation in energy savings compared to just using my 12 gauge extension cord on my outdoor 120v outlet.

    BUT:

    The Ontario government is also somewhat forward thinking with its EV strategy and they give a rebate of 50% (up to $500) for purchase of the EVSE and 50% (up to $500) for installation.

    And my realtor gave me $500 (for buying a second property from him).

    So now my install cost including tax is down to

    $858.04 / 2 = $429.02 for wall charger hardware
    +
    $1,444.14 - $500 = $944.14 for installation
    =
    $1,373.16
    less the $500 my realtor gave me is $873.16.

    Still ~185 months = ~15.4 years to recoup the costs if I'm only saving ~$4.71/month.

    BUT BUT:

    It WILL use less energy and be slightly more convenient (I won't have to haul my mobile charge cable out of the trunk every day). So I'm doing it anyway, even though it's likely a cost losing choice (at current energy rates).
     
  16. hcsharp

    hcsharp Active Member

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    Indeed you don't drive much and your rates are low. You were generous to include the realter's rebate too. I'm glad you're doing it nonetheless and you might get a lot of your investment back in increased real estate value.
     
  17. 5YJSA

    5YJSA Member

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    Agreed.

    I'm in a bit of a weird situation, where my house is so small (the only thing we could afford, really) that there is practically no real driveway. But there is a spot where I park, which may or may not be entirely within my rights, and the city has never (to my knowledge) objected to any previous owner parking there.

    So you might think that it's not a great investment for future house value...

    But at the same time, the future is electric, and all new houses in Toronto must have at least a 30 amp outlet near the parking area, so having a house without this feature will, some day soon, make it stand out as inferior, for sure.

    Every house in my neighbourhood is about 100 years old.

    I have seen only 2 others that have chargers on them so I guess I'm on the cutting edge of retrofitting.
     

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