Charging on 110 outlet

[Cottonwood]

I would not recommend using any extension cord less than 10 AWG, regardless of length, and keep the length at 50-feet or less. The Model S can detect resistance in the cord and will not allow a charge if the voltage drop is significant.

Incidentally, did you look into Destination Chargers (HPWCs) in Maine? A number of hotels and resorts have them. Some may require that you stay there, but others might allow you to charge while stopping for an extended lunch.

It's total resistance of the circuit to the car that will trigger the 75% charge current (12A->9A) safety feature. With a good starting 120 outlet (circuit) I have successfully charged with 50' #12 and #14 extension cords. Those #10 cords are pretty heavy and will only save you from 9 Amp charging on a few threshold circuits.

I recommend a good #12 50' cord with quality plug and receptacle. Here is one example: US Wire 74050 12/3 50-Foot SJTW Yellow Heavy Duty Lighted Plug Extension Cord - - Amazon.com

 

[steilkurve]

Just a word of caution. I stayed at a resort hotel that had lots of 120V outdoor plugs - used to charge the golf carts. You would think that would be a pretty good outlet. Not all worked - bad ground probably. It was a little bit older resort - circa 1995 I think - so not old just not new. These outlets charged the golf carts just fine.

Modern code certainly requires a ground and 12G wire but when you use the word "cottage" I just thought you should at least be prepared for the possiblity that the 120Vs might not be reliable.

They are brand new cottages, fairly well equipped with AC and high end appliances. I'm assuming electrical is up to code. Hoping!

 

[steilkurve]

I would not recommend using any extension cord less than 10 AWG, regardless of length, and keep the length at 50-feet or less. The Model S can detect resistance in the cord and will not allow a charge if the voltage drop is significant.

Incidentally, did you look into Destination Chargers (HPWCs) in Maine? A number of hotels and resorts have them. Some may require that you stay there, but others might allow you to charge while stopping for an extended lunch.

I did. Nonamtum Resort says I can plug while eating at their restaurant. Just want options as I was bitten before in the countryside with limited public charging and others (sadly Model S owners) hogging the charger. ;-)

 

[linkster]

Just want options as I was bitten before

Yes. Good planning has options.

When charging on 120v I try to find an outlet close to the load center or a single outlet (hopefully a 5-20) on a particular branch circuit such as a washing machine or microwave. I always continuously monitor and check all connections for excessive heat and I always travel with a 50' UMC to reduce the probability of having to use an extension. If I need to reach out >50', I deploy a 50' 12AWG 5-20 molded ended extension for both 120v and 240v charging.

 

[smilepak]

So what brand ppl recommend that can use on both 110/120 plug? I'm interested in carrying one along just in case.

Or is it better to by one 14-50 extension and use various adapters to the 14-50 and outlets?

 

[linkster]

I recommend a good #12 50' cord with quality plug and receptacle. Here is one example: US Wire 74050 12/3 50-Foot SJTW Yellow Heavy Duty Lighted Plug Extension Cord - - Amazon.com

Similar to Cott's 12AWG but with molded end 5-20's:
Amazon.com: Conntek NEMA 5-20 20-Amp T-Blade Outdoor SJTOW 12/3 Extension Cord, 50-Feet: Sports Outdoors

 

[richkae]

I am sure that some others may have advice on better tools...

I like to carry one of these with my adapters:
Klein Tools RT200 GFCI Receptacle Tester - Circuit Testers - Amazon.com

A proper voltmeter might help find the best outlet.

 

[scaesare]

I am sure that some others may have advice on better tools...

I like to carry one of these with my adapters:
Klein Tools RT200 GFCI Receptacle Tester - Circuit Testers - Amazon.com

A proper voltmeter might help find the best outlet.

Man that sounds familiar...

One thing that has come in handy are these... it lets you find a good outlet candidate without having to jockey the car all around:

Outlet Tester

Voltage Sniffer

 

[KidDoc]

I'm currently in a rental with moving and trying to sell a home hassle. It works fine at 3-4 miles per hour. If I start falling behind my dryer outlet is close enough where the Tesla UMC can reach it and that gives me 18-19 miles. Not ideal but better than trying to install a 14-50 in a rental.

 

[davewill]

They are brand new cottages, fairly well equipped with AC and high end appliances. I'm assuming electrical is up to code. Hoping!

Sometimes those AC units will be plugged into 6-20 outlets. If so, you could possibly charge at 240v if you're willing to do without AC while charging. Did you say appliances? There's also the possibility that it has an electric range plugged into a 14-50 (might only be 40a instead of 50a) or 14-30 outlet.

 

[Cosmacelf]

Btw, the NEMA 5-20 adapter will give you about 42% faster charging over the supplied NEMA 5-15 adapter. The car uses a lot of electricity in overhead when charging, so the extra amps goes directly into the battery when you can give it more...

 

[InTheShadows]

It's total resistance of the circuit to the car that will trigger the 75% charge current (12A->9A) safety feature. With a good starting 120 outlet (circuit) I have successfully charged with 50' #12 and #14 extension cords. Those #10 cords are pretty heavy and will only save you from 9 Amp charging on a few threshold circuits.

I recommend a good #12 50' cord with quality plug and receptacle. Here is one example: US Wire 74050 12/3 50-Foot SJTW Yellow Heavy Duty Lighted Plug Extension Cord - - Amazon.com

I'm not positive but I'm
Pretty sure it's not detecting resistance, it has a safety fall back feature if the voltage drop is too great, which indicates to the car that the wiring (extension cord) is inadequate.

This is why sometime at home, our car falls back to 30 amps despite all of our wires being oversized. The grid gave us voltage that was at the bottom of the allowable parameters so the car went into protection mode.

 

[scaesare]

I'm not positive but I'm
Pretty sure it's not detecting resistance, it has a safety fall back feature if the voltage drop is too great, which indicates to the car that the wiring (extension cord) is inadequate.

This is why sometime at home, our car falls back to 30 amps despite all of our wires being oversized. The grid gave us voltage that was at the bottom of the allowable parameters so the car went into protection mode.

Given that the voltage drop is a function of the amount of resistance to current flowing, and the car can determine that drop as it ramps up current, it is in effect detecting resistance.

This is as opposed to detecting an arc, measuring heat, etc...

 

[Khatsalano]

I am actually charging right now, here: Holiday Inn Auburn | Auburn, CA | Electric Car Charging Station | PlugShare on the 110V/12A outlet using a standard garden orange extension cord. I want to say it's a 30 footer. So far, the car is taking the charge and maintaining 12A for 3mph.

Yes, I know there are SCs within 15 miles of me, but I have a very early morning mission that will require 100% charge to complete.

- K

 

[TexasEV]

I am actually charging right now, here: Holiday Inn Auburn | Auburn, CA | Electric Car Charging Station | PlugShare on the 110V/12A outlet using a standard garden orange extension cord. I want to say it's a 30 footer. So far, the car is taking the charge and maintaining 12A for 3mph.

Yes, I know there are SCs within 15 miles of me, but I have a very early morning mission that will require 100% charge to complete.

- K

"Standard garden orange extension cords" aren't made to take 12A continuously for hours. i hope you didn't awaken to a big problem. You really should get a 12 or 10 gauge cord for next time.

 

[Cottonwood]

I'm not positive but I'm
Pretty sure it's not detecting resistance, it has a safety fall back feature if the voltage drop is too great, which indicates to the car that the wiring (extension cord) is inadequate.

This is why sometime at home, our car falls back to 30 amps despite all of our wires being oversized. The grid gave us voltage that was at the bottom of the allowable parameters so the car went into protection mode.

Given that the voltage drop is a function of the amount of resistance to current flowing, and the car can determine that drop as it ramps up current, it is in effect detecting resistance.

This is as opposed to detecting an arc, measuring heat, etc...

The car is doing Voltage detection, but as @scaesare says, because current times resistance causes a Voltage drop, the car can use Voltage to detect high resistance circuits. It also appears to have other algorithms to do "arc fault" like detections in software. Charging at a motel 14-50, I had evening activity of other loads fold the 40 Amps back to 30 Amps. In addition, there have been reports of load activity in the neighborhood, on the same transformer, causing the 75% current fold back.

I don't think that anyone outside of Tesla knows the complete design of the current fold back algorithm, but one trigger is definitely a drop in Voltage caused by a higher than normal resistance. My first post was to let people know that my experience is that a 50' #12 or even #14 extension cord will normally work with a Model S and not induce a current fold back situation.

In a small fraction of installations, the extra resistance between a 50' #12 and a 50' #10 cord could be the "straw that breaks the camel's back", but I believe those are a very small fraction of outlets. I do know that a #10 cord is noticeably heavier and bulkier than a #12 cord. That's why I carry a #12 cord and have never had a problem with it.

Good Luck!

 

[Rocky_H]

"Standard garden orange extension cords" aren't made to take 12A continuously for hours. i hope you didn't awaken to a big problem. You really should get a 12 or 10 gauge cord for next time.

Those outdoor lawn and garden cords are pretty heavy duty. I haven't checked the wire gauge on mine, but I would be really surprised if it's less than 12.

 

[TexasEV]

Those outdoor lawn and garden cords are pretty heavy duty. I haven't checked the wire gauge on mine, but I would be really surprised if it's less than 12.

I wouldn't be surprised at all if it's less than 12 gauge. Most extension cords sold for lawn and garden use are 16 gauge. Please do yourself a favor and check the gauge stamped on the cord.

 

[scaesare]

I wouldn't be surprised at all if it's less than 12 gauge. Most extension cords sold for lawn and garden use are 16 gauge. Please do yourself a favor and check the gauge stamped on the cord.

This is good advice. A lot of the outdoor-rated extension cords may have thicker insulation, or use a material like rubber that feels heavier, even thought the conductors themselves aren't heavier-gauge.

 

[InTheShadows]

The car is doing Voltage detection, but as @scaesare says, because current times resistance causes a Voltage drop, the car can use Voltage to detect high resistance circuits. It also appears to have other algorithms to do "arc fault" like detections in software. Charging at a motel 14-50, I had evening activity of other loads fold the 40 Amps back to 30 Amps. In addition, there have been reports of load activity in the neighborhood, on the same transformer, causing the 75% current fold back.

I don't think that anyone outside of Tesla knows the complete design of the current fold back algorithm, but one trigger is definitely a drop in Voltage caused by a higher than normal resistance. My first post was to let people know that my experience is that a 50' #12 or even #14 extension cord will normally work with a Model S and not induce a current fold back situation.

In a small fraction of installations, the extra resistance between a 50' #12 and a 50' #10 cord could be the "straw that breaks the camel's back", but I believe those are a very small fraction of outlets. I do know that a #10 cord is noticeably heavier and bulkier than a #12 cord. That's why I carry a #12 cord and have never had a problem with it.

Good Luck!

Thanks to the both of you for the explanation. I never thought of it calculating it that way. That's pretty cool.