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Charging safely at 9/12 amps?

Discussion in 'Model 3: Battery & Charging' started by RossianSpy, May 14, 2019.

  1. RossianSpy

    RossianSpy Member

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    Hi, I own a model 3 and live in a condo that has underground parking. The only outlets that are available for charging are in the storage closet next to my parking spot. The parking itself has like 15 foot ceilings and the outlet that is setup in the closet is this exact model Leviton Porcelain Lamp Holder with Pull Chain and Outlet-R60-09726-00C - The Home Depot
    So I able to ask the maintenance guys to use their ladder to run an extension cord of this kind RIDGID 25 ft. 14/3 Outdoor Extension Cord-657-143025RL6A - The Home Depot to be attached to the outlet so I could start charging the car. Now the car charges at only 9/12 amps and stays at around 102-104 volts, which is pretty low but it still charges at 3 mph. I was able to plug just the adapter directly to the car and it still only gave me 9/12 amps with the notification that an extension cord was being used. Anyway if I kept everything as is and just used to charge with the extension cord at 9 amps for constant use; would I be running into any risk of the outlet starting on fire or the cable? I thought since its only draining at 9 amps and both outlet and cords are rated at 15 amps I would be okay, but I rather get a 2nd opinion from anyone here.
    Thank you

    PS I don't have an option of installing any other outlets in there, everything has to stay as in the parking garage as it's not allowed by the management
     
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  2. SSedan

    SSedan Active Member

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    The low voltage suggests the wire run is excessively long or has poor connections. IMO continued use is risky.
     
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  3. gfunkdave

    gfunkdave Member

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    Not the best idea. That lamp socket thingy is definitely not designed for high power applications. And the fact that you have a really significant voltage drop to 102V from the nominal 120V means there is something else amiss - a loose connection possibly or something else. This is a fire waiting to happen.

    Call an electrician and find a way to put in a better charging solution. I know you said this is not an option, but think of the consequences that will befall you if your car charging starts a fire. Talk to your condo board to figure something out.
     
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  4. RossianSpy

    RossianSpy Member

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    Thank you for your feedback, what if I directly connect it without extension cord?
     
  5. Derek Kessler

    Derek Kessler Active Member

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    Still asking for trouble. The problem isn't the extension cord — it's something to do with the socket and/or the wiring leading to it.
     
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  6. RossianSpy

    RossianSpy Member

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    I was able to get more information from the maintenance guys, he said the electrical room is over 200 feet away from sure and that the wire that is run starts at 10 gauge but then goes to 12 gauge. It is all 1 line that's running across storage closets and all of them have this socket with a light bulb in it. Could that be the main cause of the voltage drop? In general is it still unsafe to charge your car with 120 volt if the distance from the breaker is very far like 200+ feet?
     
  7. SSedan

    SSedan Active Member

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    Are the bulbs incandescent or LED?
     
  8. RossianSpy

    RossianSpy Member

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    incandescent
     
  9. dhanson865

    dhanson865 Active Member

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    #9 dhanson865, May 14, 2019
    Last edited: May 14, 2019
    Anything below 114v at the socket is below spec. I wouldn't use it unless you aren't concerned about the fallout if there is a fire in those storage closets.

    The pics below are from a much shorter run that was improper. Think about that happening through 100 feet of thin wiring.

    http://i57.tinypic.com/335eb9e.jpg
    http://i57.tinypic.com/sgo8jo.jpg
    http://i57.tinypic.com/2s9qazs.jpg
    http://i60.tinypic.com/33kvzo3.jpg

    keep in mind the damage in those pics was minor because the home owner was watching it for trouble. If he wasn't there to shut that down it would have been worse.


    [​IMG]
     
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  10. SSedan

    SSedan Active Member

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    The voltage might be low due to load of that many incandescent plus your car. LED might help but this still wouldn't be a proper solution or safe.

    Talk to the association about adding EV charging. Being in a garage maybe it won't break the bank, no finish work to worry about just hang conduit and outlets.
     
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  11. RossianSpy

    RossianSpy Member

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    So for it to be safe, i'd need a dedicated line run from the breaker regardless if its 240v or 120v with proper grounded outlet off course? I had an option of having the maintenance guys install a separate 120 volt outlet, but I think it would be just using the same line that's being used by the ceiling lamp fixtures; which probably wouldn't solve the problem.
     
  12. ewoodrick

    ewoodrick Well-Known Member

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    Going from 10 to 12 to 14 gauge usisn good. At least get a thicker extension cord
     
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  13. TexasEV

    TexasEV Well-Known Member

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    Yes, EV charging should be on a dedicated circuit.
     
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  14. M3BlueGeorgia

    M3BlueGeorgia Active Member

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    Probably fine, but good to check it out.

    Note: If direct connection works out, then the probably was the gauge of the wire on the extension cord.
     
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  15. Rocky_H

    Rocky_H Well-Known Member

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    There's a spectrum on this stuff of how bad things are by how many issues are involved.
    Best/ideal: Short thick wire run, few connection points, to single dedicated outlet.
    Worst: Long run, thin wire, many connection points, sharing way too many outlets.

    Your situation is closer to the worse side than the better side, as indicated by the 102V, which is a pretty concerning low voltage. On a regular residential house situation, where you're talking about like a garage circuit that's like 50 feet of wiring distance and maybe 3 outlets on it, I would trust that pretty well. But this scenario with 200-ish feet (very long run) that goes down to 14 gauge, and has dozens of fixtures or outlets that could be turned on at any time has a lot of weak points in it. And yeah, I concur with @gfunkdave that those screw-in bulb/outlet combo things are probably a pretty weak connection point for a heavy current draw.

    So I would recommend against trying to use this for charging. If you can get something installed, that would be much better, even if it's not a very high power circuit. A 20A or 30A line at 240V is very useful charging speed. With such a long run, though, using one step thicker on the wire gauge would be a good idea.
    *Edit* I forgot--commercial building probably has 208V instead of 240V, but effectively almost the same thing.
     
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  16. M3BlueGeorgia

    M3BlueGeorgia Active Member

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    The adage "the perfect is the enemy of the good" should always be remembered in trying to get charging facilities to people in condos and apartments.

    Since people charge overnight, and therefore can't easily share a 240v or 208v connection, it is actually better to have many 120v-20A connections available than a few 240v or 208v connections.
    Also better for the people paying the electric bill, since most of the power will be taken overnight when rates are lowest.

    So my recommendation is to push for several EV outlets supplying 120v/20A, each of which would allow for 50 - 70 miles of charge overnight.
    You can have 4 of those in exchange of a single 240A/40A socket. That would scale all the way up to 60 from a full 3 phase 200A supply.
     
  17. BEPA400

    BEPA400 Member

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    The fact that this single line supplies each storage closet with light is a huge red flag to me. At each closet connection the wire is cut and connected. If you don’t know the condition of each of those connections there is a serious risk that if one is poorly connected, under constant 1500w load, it will heat up. A low voltage like 102 is a sign of poor connection. And long run. Even if it doesn’t cause a fire, you will be blowing the circuit breaker every time a couple people turn on lights.
    A 200 foot run for a dedicated 15A socket is not a big deal. If they don’t want to do that, insist on paying for it yourself. It will be better than nothing, and way better than a fire.

    Oh- and for perspective, consider that 20 volts that is ‘lost’ on the way. It’s not lost. That is 20/120 = 17% of all that charging power that is constantly working to heat up the wires and connections. The more I think about this the more it scares me.
     
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  18. SSonnentag

    SSonnentag Rocket Scientist

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    On one vacation trip we stayed in a KOA cabin. I ran a 15' 10-gauge extension cord from an outside-wall-mounted outlet on the cabin to my car and was getting only 106V. The car wouldn't keep charging at anything over 10A, so I dialed it down to 8A for the 4 days we were there. I have no idea why their voltage was so low, but I figured that with only 8A being drawn on a circuit, any resulting fire wouldn't be my fault. :)
     
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  19. Rocky_H

    Rocky_H Well-Known Member

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    I was addressing this particular situation, and I don't think it comes anywhere near either "perfect" or "good", or even "sufficient" or "reasonable". It's pretty bad.

    But the rest of your point as a generalized statement about other apartment and condo situations is validly noted. Getting several low power outlets available to the residents for charging would be good. However, I would still say that from a cost/benefit analysis, 240V connections are still the way to go. It is the same installation cost and wire based on the amps, regardless of whether it's a 120V or 240V endpoint, but way more usefulness with the extra voltage, so it does make more sense to go that way.
     
  20. gfunkdave

    gfunkdave Member

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    I mean, if you're going to go to the trouble of running a new circuit to a dedicated socket, there is no reason not to run a 208/240V circuit. The main material cost of running a new circuit is the wire, which is the same for 120 or 208/240. Labor is the same too.

    Now, if you want to engage the condo board on getting the garage ready for electric car charging in general, that's an entirely different conversation that depends on a lot of other factors - the board's willingness to spend money, the available physical infrastructure in the building, etc. But I think having a handful of EV outlets spread around the garage would be a good base step.
     
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