help with 14-30 adapter and charging times in dryer

[jlucero]

please forgive me, i know nothing about inverters/electricity/voltage etc...

i usually charge at my home with a NEMA 14-50, and all is good and fine. i will be traveling to visit a friend with no public chargers nearby and will charge at him his home. he has had other friends with teslas charge at his house and claims that with a NEMA 14-30 adapter plugged into the dryer they gets max 6 miles per hour. he wasnt 100% sure, and im hoping he has that stat wrong. i have another friend with the same setup and claims that he gets 20-25 miles per hour....he states that at a minimum he house should be pulling 40Amp, and give anywhere from 20-30 miles per hour charge.

why the difference? does it depend on what kind of tesla you have? or does it depend on the house?

im including photos of the adapter and dryer connection for my friend who claims 6 miles an hour...anyone have an idea what i should be getting per hour charge?

 

[jerry33]

1. You should never ever be pulling 40 amps on a 14-30 for EV charging. 24 amps is the maximum safe charge allowed by code. By using an adapter you will need to check the setting on the charge screen before every charge to make sure that it's still at 24 amps.

2. If the 14-30 adapter is 14-30 to 5-15 or 5-20, then 6 amps is all you'll get because that's all that is allowed. If the adapter is 14-30 to 14-50 then you should get the full 24 amps.

3. Some folks have been successful in getting a real 14-30 adapter from the local Service Centre. Give it a try, you might get lucky. This adapter is set for the safe maximum of 24 amps so you won't have to check to be safe.

 

[Petra]

If you're plugging into a NEMA 14-30 outlet, it should be supplying 240V and your car should draw no more than 24A (80% of the 30A breaker's max). If I remember correctly, that should work out to about 18 miles per hour of charge. If you're connecting with an actual Tesla NEMA 14-30 connector, then you just plug in and the car and Tesla EVSE take care if the rest. If you're using an aftermarket adapter to go from a Tesla NEMA 14-50 connector to a 14-30 plug, then you'll need to manually dial the car down to 24A or you'll pop the breaker.

 

[jlucero]

thanks guys! im hoping i get the 24amps!

 

[jlucero]

i have a 70D by the way...not sure it matters or not.

 

[Petra]

thanks guys! im hoping i get the 24amps!

Just looked at your photos and both seem to be 14-30 (Tesla 14-30 connector and 14-30 outlet), so you should be good to go.

I have a 70D as well, so the info I posted a couple posts up still applies (though, the AC charging stuff is pretty much the same for all Model S).

 

[Chris TX]

Yes, you should be able to safely pull 24A from that outlet, but if your friend is only getting 6MPH out of it, the car is sensing some line noise and dialing down the amps. Or, they could just be wrong about the charge rate

 

[jerry33]

i have a 70D by the way...not sure it matters or not.

Doesn't matter.

 

[mikeash]

To get the approximate MPH charging rate, take volts multiplied by amps, then divide by 1,000 and multiply by 3. For example, here the voltage should be about 240V, multiply by 24A gets you 5760, divide by 1000 and multiply by 3 gets you roughly 17MPH charging. For another example, a lot of public J1772 chargers are 30A at 208V, which gets you about 18MPH.

Just to repeat what the others said, on a NEMA 14-30 you shouldn't charge at more than 24A. If the car wants to, then dial it down in the car. If you can locate an official Tesla 14-30 adapter then this will happen automatically, but those are getting very hard to come by since they discontinued it.

 

[Rocky_H]

Maybe the picture was added later (possibly why some of you missed it and were commenting about manually dialing down the current), but that is an official Tesla 14-30 adapter for the mobile charge cable, so it will handle the current correctly automatically--no manual dialing down needed.
As to the charging speed, @mikeash 's calculation works, but I just do it a little quicker and easier given a charging rate that I DO know. It does go by power, but since most people don't bother with 120V sources, and we're comparing two that are on the same 200+ volt systems, you can simplify by just looking at the current difference. On a 14-50 outlet, at 40 amps, it's 29 miles per hour. So you can set up a ratio of 29/40 = X/24. Solve for X. So you use your middle school cross-multiplying thing, and 29 times 24 equals , divided by 40 equals 17.4, which you can see does come out about the same as mikeash's method.
*Edit* fixed the calculation to use 40A and 24A, not 50 and 30.

 

[mikeash]

I saw the picture but didn't recognize it as the official adapter. Oops!

 

[jlucero]

again, dumb question here...

1. by looking at the photo of the wall dryer outlet, that is a 240V and 30 amp wall outlet?

2. is the situation the same with a NEMA 10-30 wall dryer outlet and the 10-30 adapter? (my parents have an older house with the older 10-30---on that wall outlet it says 30A-125/250V)...would this be similar situation? 240V or 250V and 30 amp generating the same 17-18 miles per hour?

i appreciate everyone telling me about manually dialing down the amps. even if it is a tesla 14-30 adapter, still a good idea to get in the habit of dialing down power to 24A in the car?

 

[mspohr]

2. If the 14-30 adapter is 14-30 to 5-15 or 5-20, then 6 amps is all you'll get because that's all that is allowed. If the adapter is 14-30 to 14-50 then you should get the full 24 amps.

I usually get 12 amps from my 5-15 Tesla adapter which seems right at 80% of 15 amps

 

[mikeash]

Yep, the outlet is a 14-30 which your adapter should fit. I wouldn't worry about dialing down the amps manually if you're using the official adapter, that's only needed when you're using an unofficial adapter that the car doesn't know about.

A 10-30 will provide the same amount of power. The only difference between the 10-30 and the 14-30 is that the 14-30 has an extra pin for the ground, while the 10-30 has no ground and instead relies on its neutral for that purpose. The car doesn't care either way, and you'll get the same rate of charge. If you can't find an official 10-30 adapter, you can probably dig up an unofficial adapter which would plug into the 10-30 and provide you with a 14-30 receptacle you can use with that official adapter, which would save you from having to mess with the amps.

 

[Electricfan]

Did your friend say that others using the outlet had tripped the breaker? They may have dialed down the current to avoid that, hence getting only 6 mph.

 

[jerry33]

again, dumb question here...

1. by looking at the photo of the wall dryer outlet, that is a 240V and 30 amp wall outlet?

2. is the situation the same with a NEMA 10-30 wall dryer outlet and the 10-30 adapter? (my parents have an older house with the older 10-30---on that wall outlet it says 30A-125/250V)...would this be similar situation? 240V or 250V and 30 amp generating the same 17-18 miles per hour?

i appreciate everyone telling me about manually dialing down the amps. even if it is a tesla 14-30 adapter, still a good idea to get in the habit of dialing down power to 24A in the car?

If it's a Telsa 14-30 adapter there is no need to dial down because the adapter has a diode in it that tells the car which adapter is used and will correctly set the current, only a third party adapter requires it.

 

[Rocky_H]

again, dumb question here...

1. by looking at the photo of the wall dryer outlet, that is a 240V and 30 amp wall outlet?

2. is the situation the same with a NEMA 10-30 wall dryer outlet and the 10-30 adapter? (my parents have an older house with the older 10-30---on that wall outlet it says 30A-125/250V)...would this be similar situation? 240V or 250V and 30 amp generating the same 17-18 miles per hour?

i appreciate everyone telling me about manually dialing down the amps. even if it is a tesla 14-30 adapter, still a good idea to get in the habit of dialing down power to 24A in the car?

They aren’t dumb questions. This is a new realm that most people don’t know about until they research it some.


(1) Yes, you can identify outlets from a photo, because they have very specific pin layouts. Use this reference table.

NEMA connector - Wikipedia, the free encyclopedia


(2) @mikeash answered that.


(3) “even if it is a tesla 14-30 adapter, still a good idea to get in the habit of dialing down power to 24A in the car?”



You won’t need to dial it down to 24, because it will be at 24 anyway. If you are using an official adapter and plugging directly in to an outlet that the adapter is made for, the car won’t LET the current level go too high. It WILL be correct, so you don’t need to turn it down. I could add a note of preference on that. For both the mobile cable and the wall connector cable, they do get kind of hot when they are running at their maximum rated level (40A and 80A, respectively). Some people will pull it back about 5 amps or so, just to keep it a little cooler.

 

[jlucero]

Rocky and all...thanks for the kind responses...I've learned a ton!

 

[supratachophobia]

I get 17-18mph at the in-laws using the 14-30.

 

[Gremlin]

please forgive me, i know nothing about inverters/electricity/voltage etc...

i usually charge at my home with a NEMA 14-50, and all is good and fine. i will be traveling to visit a friend with no public chargers nearby and will charge at him his home. he has had other friends with teslas charge at his house and claims that with a NEMA 14-30 adapter plugged into the dryer they gets max 6 miles per hour. he wasnt 100% sure, and im hoping he has that stat wrong. i have another friend with the same setup and claims that he gets 20-25 miles per hour....he states that at a minimum he house should be pulling 40Amp, and give anywhere from 20-30 miles per hour charge.

why the difference? does it depend on what kind of tesla you have? or does it depend on the house?

im including photos of the adapter and dryer connection for my friend who claims 6 miles an hour...anyone have an idea what i should be getting per hour charge?

I'm at a rental for the last week. Yeah. Been charging at Cape Code home using 30 amp 50 foot extension cord. I get 18 miles an hour. dryer is 220 volts. see photo. The local Tesla store will carry this 14-30 adapter as its not for sale at the online store.