Will tesla charge with 110v while using an extention cord

Will tesla charge with 110v while using an extention cord

On my roadtrip I am going to have, the hotel we are staying at offers charging but only with 110v. I am probably going to use an extension cord. Will it charge with an extension cord? And what kind of extention cord should I buy? | 27. Februar 2018

Yes but very slowly. At 15 amps about 5-6 miles per hour (7-8 for Model 3). Any extension cord rated for the current to be used will work.

Should_I | 27. Februar 2018

Thick as possible 10gauge if you can find it and you do not want to get carried away with length, 12gauge if you have to but then really keep the length to a minimum.
I would expect to turn down amperage too. Will default to 12amp but I would likely dial it down to 10-11 and then give it a few minutes and check the voltage, if getting below 120volt much I would dial the amperage back a little more. I would check after an hour or two to make sure the outlet is not getting hot.
Not going to get much in the way of mileage added but will be better than nothing.

rxlawdude | 27. Februar 2018

@george, I think your estimates are way too optimistic. More like 3-4 mph for a Model S, and 4-5 mph for a Model 3. A long extension cord will further decrease any theoretical maximums.

christiansnook123 | 27. Februar 2018

Is 25 feet too much? | 27. Februar 2018

25 ft. is not too much.

@rxlaw: You may be right but at 1.8 kW a Model S will theoretically gain about 6.4 rated miles per hour. I derated that a bit. Model 3 theoretically 7.8 rated miles per hour. 7-8 is probably a little optimistic.

12 gauge wire equivalent is used to wire up 20 amp/120 volt branch circuits as I recall.

jordanrichard | 28. Februar 2018

I have a 25 ft extension cord and have used it to plug into a 110v outlet. It has to be heavy gauged wiring. A standard extension cord has wire strands that are too small and the car will essentially detect this and not allow the car to charge.

Rocky_H | 28. Februar 2018

When I checked the "heavy duty" types of extension cords I had with really solid rubber jacketing for outdoor use, I thought they would be thick enough gauge. No way. They were both 16 gauge wire, which is way too thin for long term current use, so don't assume on that. 12 gauge at least will be fine for the shorter lengths like 25 feet that you're talking about.

@georgehawley, Oh, you were assuming a higher 20A circuit, which is why you were stating those higher miles per hour charging numbers. We were assuming regular 15A circuit, which will be 3-4 miles per hour.

rxlawdude | 28. Februar 2018

@Rocky, can you even set your Tesla to charge at 120V using the standard adapter? I thought that receptacle type can only handle 15A.

reed_lewis | 28. Februar 2018

You can still set the amperage when charging no matter the voltage.

When you use the 120V plug, it only charges at 12Amps which is 80% of 15 amps.

They have for purchase a 5-20 outlet adapter for 110V that has a horizontal and vertical plug blade. That is supposed to be a 20 amp circuit, and you can charge a little faster.

Check out this page for all the adapters:

Rocky_H | 28. Februar 2018

@rxlawdude, Maybe the wording is strange, but I don't follow your question.

"@Rocky, can you even set your Tesla to charge at 120V using the standard adapter?"

Well, you don't "set" the voltage. The car just senses and uses whatever is there, even if that's not the expected type of voltage that the adapter type would normally have on it. That is really handy for things like using the Tesla 14-30 for a dryer outlet to connect to a TT-30 camper outlet, which is actually 120V 30A. Which do you think is "the standard adapter"? The UMC pack originally comes with a 5-15 and a 14-50.

Quote: " I thought that receptacle type can only handle 15A."

So you talking about the 5-15?

rxlawdude | 28. Februar 2018

You set the amperage. But a standard 5-15 receptacle and Tesla adapter limits draw to 12A.

Rocky_H | 01. März 2018

@rxlawdude, Quote: "You set the amperage. But a standard 5-15 receptacle and Tesla adapter limits draw to 12A."

Oh, OK. I think I see where your question is. This was a little confusing from the start. The OP said 110v, but didn't specify the amps. Then @georgehawley was talking about 15A and 1.8kW and 5-6mph of charging. The 15 part isn't quite right, but the power and mph rate would be about correct for a 5-20 outlet. If you have the Tesla 5-20 adapter with an actual 5-20 outlet, then it follows the 80% rule, and can draw up to 16 of 20 amps, and you can get about 5-6mph rate. So that's where we thought maybe @george was talking about the other type of 120V outlet.

Tesla-David | 01. März 2018

My HPWC is currently inoperable and we have been forced to use our UMC and 110/120V extension cord to charge both our MS and M3 in our garage. It is worked much better than I ever imagined, and we are averaging 3.4 mph of mileage to our MS and 5.2 mph of charge to our M3 per hour. We always carry a 100 ft extension cord in our Frunk and have used 120V charging at Hotels in Portland OR, and Vancouver BC repeatedly. It has worked well in every instance, so don't hesitate. It is a great alternative and lets the Hotel managers know they need to provide EV charging infrastructure in the future.

darayush | 18. August 2019

I live in a Condo in Vancouver and they gave allowed me use of an outlet with an extension cord. I used a brand new 14/3 gauge 25’ Cord. I was getting about 9km charge at 112v and 12amps. However a few hours later I got a notification from the app that the power supply was interrupted. I went and checked and the plug was pulled off the wall socket and when I tired to plug it back in there was no power to the outlet anymore. I ended up using an outlet in the visitor parking with no incident but I was directly plugged into the wall this time with the charger. My building manager is going to find out what happened but I am trying to understand this as well. I am assuming it tripped the breaker but why? Would a 12 gauge work better and would lowering the amps in the car to say 10amps help.

dchuck | 18. August 2019

The thinner the wire the higher the energy lost to heat, the hotter the wire gets the more resistance to the energy flow. So your car charged fine until the wiring heated up, then the breaker popped when the current draw became too high.

Lowering the amps keeps the temperature down and of course a thicker cable has less resistance and also creates less heat.

Earl and Nagin ... | 18. August 2019

12 gauge would definitely be better. 10 would be even better. Lowering the charging current (amps) would also help (but would take even longer to charge).
As to why it was unplugged? Someone unplugged it.
Why? Anyone's guess.
Unplugging while under the full charging load could have caused a power surge that could have tripped the breaker.

ckcland2 | 18. August 2019

I use a the "ProStar 10 Gauge SJTW 3 Conductor 50 Foot Extension Cord With Lighted Ends - Orange" I bought on amazon 3 years ago. Use it approx 4 times a year and it works like a charm. Cost was about $50.

stevenmaifert | 18. August 2019

On a recent family visit, I used a 100 foot 12 gauge extension cord. I coiled the excess. The MS charged at 3 miles per hour. After several hours of charging, I checked up on everything to find the coiled portion of the cord warm to the touch, possibly due to some inductive reactance because of the coiling?. I re-positioned the car, and was able to just connect with the Gen 1 UMC without the extension cord. To my surprise, the charge voltage jumped from 114V to 120V and rate of charge increased to 4 mph. Moral of the story; If you must use an extension cord, use the shortest length possible, and don't coil any excess.

Devilstower | 18. August 2019

I use a 10 gauge cord with an old J1772 carve cord as my daily means of charging my 3. Gets about 7 mph, which has always been plenty.

Superchargers are great on the room. I’ve never needed anything quicker at home.

Devilstower | 18. August 2019

I use a 10 gauge cord with an old J1772 carve cord as my daily means of charging my 3. Gets about 7 mph, which has always been plenty.

Superchargers are great on the room. I’ve never needed anything quicker at home.

andy.connor.e | 19. August 2019


14 gauge wire for 12A is fine. 12 gauge wire would result in probably less losses through the wire, considering your run is only 25ft you shouldnt experience much losses.

I am sure that the breaker tripped. On a 15A breaker, i can run my space heater which is 1500W, or 12.6A in a 120V outlet. Breakers are rated for 80% of their trip rating, so a 15A breaker is rated for 12A continuous pull. What i imagine happened in your scenario, is that the circuit you had your car plugged into was also tied into other outlets, lights or just something else. And since your car was putting that breaker pretty much at its capacity before tripping, almost anything extra on that circuit would trip the breaker.

Similar thing happened with me when i was using my space heater. I plugged my computer into an outlet on the same circuit and the breaker tripped in like 10 seconds. So im sure that someone plugged something into the same circuit at some point and it tripped the breaker.

Techy James | 19. August 2019

Only concern I would have with 110 charging is if the outside temp was below freezing then battery conditioning could use all your power to warm the battery of in extremely cold actually use more than provided current from wall outlet for warming the battery.

andy.connor.e | 19. August 2019

+1 @Techy

Car will use more energy that what you're taking out of the wall to warm the battery.

darayush | 11. September 2019

Actually I have had no issues using the 14/3 gauge cord anymore and I get the same rate of charge compared to plugging it directly into the wall outlet. It so happened that one of the strata members was not aware of the plug being approved so he turned off the breaker and disconnected the plug. The building manager sorted it out and it’s worked perfect since then. Thanks to everyone’s feedback.

andy.connor.e | 11. September 2019

Ya from the previous messages, it sounded like your setup was fine.