Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Corded mobile connector with NEMA 14-50 to 5-15 adapter?

Hearing that new deliveries will no longer come with a mobile charger, I’m wondering if i were to just buy the corded connector (NEMA 14-50) if I can still have the option of plugging into a standard 120v NEMA 5-15 plug with an adapter. If the connector automatically senses input amperage it seems that could work? The advantage vs the gen2 mobile connector would be the 40a charge vs 32a when plugged into a 14-50. I still want the option of a 5-15 for peace of mind.
 

jmaddr

Active Member
Mar 29, 2019
1,165
1,161
Florida
Adapters are never a good. Even if the corded MC could support 120V, there would be no way for it to know what amperage to limit (15A breaker? 20A?). Bad idea.

Why not purchase the UMC that allows multiple pigtails? You won’t miss the extra 8A. Further, supposedly it will eventually be 1/2 the price too ($200 vs $400 for the corded version). It is still listed as $275 and out of stock unfortunately as is the CMC.
 

Rocky_H

Well-Known Member
Feb 19, 2015
7,941
10,060
Boise, ID
If the connector automatically senses input amperage it seems that could work?
It doesn't, though. All of these cables will happily detect and use whichever voltage they are getting, whether 120V or 240V. That's not an issue. But it does not automatically detect and adjust the amps. There isn't really any way for that to happen. So what they rely on is that for the cables with the changeable adapters, the adapter itself has a chip in it, which tells the cord the proper amp limit based on what type of plug it is. The corded mobile connector doesn't have switchable adapters, so it doesn't have a mechanism for enforcing a different amp level than the maximum it can do.
 
  • Like
Reactions: ucmndd

ucmndd

Well-Known Member
Mar 10, 2016
8,531
16,626
California
No. Don't do that.

If the connector automatically senses input amperage

This is not a thing, there's no way to "sense" how much amperage a circuit can safely draw. This is why we have different physical plugs for different current requirements. The interchangeable plug heads on the regular UMC have a resistor in them which signals to the unit which plug is installed and how much amperage the car is allowed to draw based on that plug. The corded mobile connector doesn't have that, so you'd have to rely on the car's amperage setting (which is notoriously flaky) to not overdraw the circuit.
 
  • Informative
Reactions: Rocky_H
yes but only do it if you know about making cables and how to do it safely.

For example tesla was sold out of the various adapters every time i needed a different one. and the car only came with the 14-50 and the 5-15 adapters. So i made ones to the plugs i need everything from a welding outlet to the 120v RV plug. The important thing is to make sure the car doesn't draw too much juice. all my adapters use the 14-50 tesla plug so the car thinks it can draw 40A but in the case of the RV plug it is a 30A breaker so it can only draw 24A safely so as soon as the car detects its plugged in I'm at the screen adjusting the max amps down to 24A. Same with other adapters I've made I've labeled each one to the max amps it can draw (80%) so i don't forget or anything. its pretty easy but unless you know what wire goes where for each plug youre connecting to dont bother with it and just buy the proper plugs.
 
Clearly not the case the OP was bringing up, but I HAVE had maximum amps automatically reduced. I don't know if it was detected by the Gen 1 UMC or the Model S itself, but instances where I've used an extension cord (both 120V and 240V), the maximum amp draw was reduced on the center-dash charging screen. There was also an in-car message, but its been so long I can't remember the exact wording...I think it was something along the lines of "Extension Cord Detected; Maximum Charge Reduced".
 

Rocky_H

Well-Known Member
Feb 19, 2015
7,941
10,060
Boise, ID
Clearly not the case the OP was bringing up, but I HAVE had maximum amps automatically reduced. I don't know if it was detected by the Gen 1 UMC or the Model S itself, but instances where I've used an extension cord (both 120V and 240V), the maximum amp draw was reduced on the center-dash charging screen. There was also an in-car message, but its been so long I can't remember the exact wording...I think it was something along the lines of "Extension Cord Detected; Maximum Charge Reduced".
Oh, well yeah, but that's a safety cutback system kicking in because it detects really high resistance because your extension cord probably has wire that's too thin. That's not a standard system of detecting something exact and setting a "proper" amount of amps.
 
Clearly not the case the OP was bringing up, but I HAVE had maximum amps automatically reduced. I don't know if it was detected by the Gen 1 UMC or the Model S itself, but instances where I've used an extension cord (both 120V and 240V), the maximum amp draw was reduced on the center-dash charging screen. There was also an in-car message, but its been so long I can't remember the exact wording...I think it was something along the lines of "Extension Cord Detected; Maximum Charge Reduced".
i charge daily on a 120v 15A outlet and set the car to 10A (I don't do the full 12A because there are a few lights and such on the same circuit and i don't wanna overload the damn lines). It is plugged in via a 100ft extension cord and I've never gotten any such warnings in the last 3 years.

The only time mine drops amps is when artillery goes off and shakes the house which vibrates the UMC sometimes causing it to drop to safe mode, (basically a few times a month) Or if i plug in my compressor while the car is plugged in the UMC notices the droop and goes to safe mode. but in both cases i just say stop charging and then start charging and its back to normal.
 

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top