120 volt 15 amp extension cord?

dweeks · Nov 28, 2014

I should be getting my Model S in early December!

While I'll do most of my charging at home or at Superchargers, I often park at Phoenix Sky Harbor airport. One of the parking facilities has standard household 120 VAC 15 amp outlets available for electric vehicles.

I know the charging rate is slow, but if the car is plugged in for 3-4 days while I'm on a trip, it'll be fully charged when I get back, thus eliminating a Supercharger stop on the way to Tucson or Flagstaff.

I believe the car comes with an adapter to fit the UMC to a household outlet. I have not yet parked at this parking company location, so I don't know how far the outlet is fro the parking stall, so I don't know if I'll need an extension cord.

If I do, what gauge should the extension cord be? I doubt it would need to be more than 15" feet long.

Are there any other issues I need to be aware of?

Cottonwood · Nov 28, 2014

Tesla say no extension cord.

That being said, for up to 25 feet of extension cord, 14 gauge should be fine. For longer, use 12 gauge, and if you are really obsessive, you can buy 10 gauge extension cords.

islandbayy · Nov 28, 2014

Get a 10 Gauge. The sustained current over a distance, the voltage can drop. Using 10 Gauge (Not very expensive, maybe 25% more then a 12 or 14 gauge) will virtually eliminate the voltage drop for the currents being used. And most 10 gauge cords are 20 amp, so if you have the 20 amp adapter and the outlet is a 20 amp (common with commercial installations), you would charge 33% faster.

Cosmacelf · Nov 28, 2014

You'll find that you can only find low gauge cords in the longer lengths. So you'll be hard pressed to find a 15' 12 gauge cord. For am airport plug I wouldn't feel good about using an extension cord. Find a spot within 20' and just use the included umc.

dhrivnak · Nov 28, 2014

One can get a 15' or even 50' 12 gauge cord. You likely need to look hard as they are not common but they are available. I got a nice 15' and 50' from Lowe's and have an old 40' that is 12 gauge and all work fine. One day for and Earth day event I put two 12 gauge cords together as I needed 90'. I charged for 6 hours with NO issues. And this is with my Roadster which charges at 15 amps not the 12 I am told with the Model S. They are good quality cords and always travel with the 15' in the back of the car.

linkster · Nov 28, 2014

I agree with all previous posters. However, I deploy a 5-20 terminated 12AWG for 25 - 50' and a 5-20 terminated "Yellowjacket" 10AWG for 100'.

Might the airport receptacle actually be a NEMA 5-20 (identified by a sideways "T" neutral)?

Also, I would definitely procure all additional Tesla UMC adapters.

If you are not familiar with effective and SAFE extension cord charging, you may consider having TonyWilliams of QuickChargePower build you a very slick 50' UMC that takes the guesswork out of the equation.

Quick Charge Power

Cosmacelf · Nov 28, 2014

linkster said:
If you are not familiar with effective and SAFE extension cord charging, you may consider having TonyWilliams of QuickChargePower build you a very slick 50' UMC that takes the guesswork out of the equation.

Quick Charge Power

Sounds like a cool idea, but when I went to that site, I didn't see a 50' tesla UMC for sale.

And yes, do buy the Tesla NEMA 5-20 adapter. Commercial locations are likely to have 20 amp receptacles...

ItsNotAboutTheMoney · Nov 28, 2014

Cosmacelf said:
Sounds like a cool idea, but when I went to that site, I didn't see a 50' tesla UMC for sale.

And yes, do buy the Tesla NEMA 5-20 adapter. Commercial locations are likely to have 20 amp receptacles...

25' 10/3 15A
Polar/Solar 1787 10/3 15-Amp SJEO Outdoor Extension Cord with Lighted End, 25-Foot - - Amazon.com

25-Foot 10-Gauge SJTW Pro Glo Lighted Outdoor Extension Cord w/Ground Monitoring, Green - - Amazon.com

Shorter cables seem to be for higher power.

linkster · Nov 28, 2014

Cosmacelf said:
Sounds like a cool idea, but when I went to that site, I didn't see a 50' tesla UMC for sale.

I sent Quick Charge Power my UMC and $375 (includes return shipping) and Tony "stretched" it to 50'. After reading the below beyond scary thread, i think it's important for owners to consider this Tesla non-approved, "use-at-your-own-risk" option.

Adventures in charging: too long an extension cord flips circuit breaker?

Cosmacelf · Nov 28, 2014

linkster said:
I sent Quick Charge Power my UMC and $375 (includes return shipping) and Tony "stretched" it to 50'.

That's a great idea. I should ask Tony if he does that as a regular service/product.

Plug Me In · Nov 30, 2014

I have a 15' 15A cord which I believe is a 12g I got from Home Depot. I use it pretty regularly on road trips, including a few occasions at RDU airport. It's sometimes difficult to fit the adapter into an outlet that has a flip up cover and the extension cord helps with this. I routinely get 3 miles/hr, rare occasions 4 with the cord.

BTW it's a good idea to call the airport parking people and confirm that it's OK to charge on their outlets.

ljwobker · Dec 9, 2014

You definitely want a 12AWG cord if you're going to be doing any real charging... and keep it as short as you can manage. The cord is basically a big resistor that saps energy... although once you get up to 12AWG the drop off is not that big a deal. Finding 10AWG cords isn't all that easy and the incremental difference is pretty small.

If you're interested in the numbers: Voltage drop calculator

But you definitely do NOT want to do what I originally did, which is buy a 50 foot, 16AWG cord and plug in with that... you end up dropping so much voltage in that long, thin wire that the car often stops charging -- thinking there's a problem with the circuit.

dsm363 · Dec 9, 2014

I bought the Polar Solar 10G 25' cord linked in post 8. Seems to work well so far.

Cottonwood · Dec 9, 2014

dsm363 said:
I bought the Polar Solar 10G 25' cord linked in post 8. Seems to work well so far.

That will certainly work, but may be overkill. Thinner wires weigh less, and take less storage space.

It all has to do with the length of the extension cord. At 25 feet, 14AWG is fine, at 50 feet, you want at least 12AWG, and at 100 feet, you want 10AWG. A thicker wire than these guidelines will always work. Also, remember that daisy chaining extension cords can add resistance in the connections.

Lloyd · Dec 9, 2014

Cottonwood said:
That will certainly work, but may be overkill. Thinner wires weigh less, and take less storage space.

It all has to do with the length of the extension cord. At 25 feet, 14AWG is fine, at 50 feet, you want at least 12AWG, and at 100 feet, you want 10AWG. A thicker wire than these guidelines will always work. Also, remember that daisy chaining extension cords can add resistance in the connections.

Remember also that you need to add in the length of the wire from the breaker to the plug. If you have a 50 foot 14awg cord and and 75 foot #14 wire to the plug, it may not be enough! Bigger is better if you don't mind carrying it.

dsm363 · Dec 9, 2014

Thanks. It's mainly for my garage since the 110V outlet is too far away from the Roadster for the UMC to reach. It's still portable enough but is heavy.

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120 volt 15 amp extension cord?

dweeks

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Cottonwood

Roadster#433, Model S#S37

islandbayy

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Cosmacelf

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dhrivnak

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linkster

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Cosmacelf

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ItsNotAboutTheMoney

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linkster

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Cosmacelf

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Plug Me In

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ljwobker

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dsm363

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Cottonwood

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Lloyd

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dsm363

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