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

Charging Rate of 15amp Adaptor into 32amp Outlet

This site may earn commission on affiliate links.

John Rogers

White LR AWD Mod 3 FSD AB
Feb 4, 2020
39
16
Tarneit, Australia
My question concerns the adaptors that come with the Tesla Mobile Connector. Although my car will come with two adaptors with Australian plugs, the principle is the same for US, UK or European adaptors.

My 240 volt mobile charger will come with a 10 amp adaptor and a 15 amp adaptor. I understand that the 15 amp adaptor will charge at 3.56 kW when plugged into a 15 amp outlet. I would like to know what rate it will charge at when plugged into a 32 amp outlet. Will it be 3.56 kW or 7.6 kW? Does the adaptor or plug limit the charging rate, as I suspect, or does the power available via the outlet limit the charging rate?

I ask as, in addition to my Zappi wall connector, I am having a 240 volt 32 amp outlet installed as a backup. I already have 10 amp and 15 amp outlets.
 
My question concerns the adaptors that come with the Tesla Mobile Connector. Although my car will come with two adaptors with Australian plugs, the principle is the same for US, UK or European adaptors.

My 240 volt mobile charger will come with a 10 amp adaptor and a 15 amp adaptor. I understand that the 15 amp adaptor will charge at 3.56 kW when plugged into a 15 amp outlet. I would like to know what rate it will charge at when plugged into a 32 amp outlet. Will it be 3.56 kW or 7.6 kW? Does the adaptor or plug limit the charging rate, as I suspect, or does the power available via the outlet limit the charging rate?

I ask as, in addition to my Zappi wall connector, I am having a 240 volt 32 amp outlet installed as a backup. I already have 10 amp and 15 amp outlets.
The adaptor dictates the max charging rate. The mobile connector tells the car the max amperage/power based on which adaptor is being used.
 
Those adaptors are smart little buggers.
It's a simple but smart system they use. Each adapter has a small resistor in it between two of the pins. The mobile connector is then able to read the value of how big the resistor is. It then has a lookup table where each size resistor corresponds to a certain number of amps, and then that max amp value is announced to the car.
 
Thank-you for the technical details Rocky_H. My thinking is to either modify the earth pin of a 30 amp US plug or else replace it with an Australian 32 amp plug and transfer the resistor.

30 amp plugs.jpg


Australian 32 amp plug and US 10-30 adaptor.
 
Thank-you for the technical details Rocky_H. My thinking is to either modify the earth pin of a 30 amp US plug or else replace it with an Australian 32 amp plug and transfer the resistor.

View attachment 508037

Australian 32 amp plug and US 10-30 adaptor.

A better solution would be to obtain a US style outlet/plug and build an adapter towards the Australian 32A outlet. The latter you can get at your local hardware store, and the former from US or China (ebay is a good source). Then you need a small amount of 10 AWG wire.

Or even just install yourself a US-style outlet (NEMA 6-30) and put it in the wall.

Does Tesla not make adapters for Australia? The question implies it, but I find that odd.
 
Last edited:
Thank-you for the suggestion. Tesla does make Australian 10 amp and 15 amp adaptors but I would be surprised if they made 3 flat pin 32 amp ones as they are not commonly used. I think your idea of using a NEMA 6-30 outlet is a far superior solution to mine. I will make it into a power board with an Australian 32 amp plug. Thank-you user12_nr, Rocky_H and pdp1.
 
Thank-you for the suggestion. Tesla does make Australian 10 amp and 15 amp adaptors but I would be surprised if they made 3 flat pin 32 amp ones as they are not commonly used. I think your idea of using a NEMA 6-30 outlet is a far superior solution to mine. I will make it into a power board with an Australian 32 amp plug. Thank-you user12_nr, Rocky_H and pdp1.

By the way, how will you obtain the U.S. adapter (and the outlet part)? I checked and it is near impossible to obtain these items overseas unless you have contacts in the U.S. who will send you them.

I think it is only recently that international Teslas could accept 32A single phase (16A was the limit before), so maybe they just have not updated their Australian outlet plugs.
 
Fortunately I am visiting my daughter in Washington State in July. I will also stock up on Sodastream sugar free Dr Pete and Root Beer.

Or you can get here for $65 + $8.95 + $7 shipping to Australia. Only $30 more than at Tesla.

The Chinese are shipping the twist lock plugs for some reason.

L14-30 Twist-lock Adapter for Tesla™ Model S™/X™/3™ Gen 2 – EVSE Adapters

30 Amps NEMA L14-30R Twist Lock 4-Wire Electrical Female Plug Receptacle Lock 619175279847 | eBay

 
It's a simple but smart system they use. Each adapter has a small resistor in it between two of the pins. The mobile connector is then able to read the value of how big the resistor is. It then has a lookup table where each size resistor corresponds to a certain number of amps, and then that max amp value is announced to the car.

That's true of the older Gen1 Mobile Connectors, but the Gen2 Mobile Connectors shipped with the Model 3 (and current-production Ss and Xs) uses a small chip in the plug/adapter to communicate the plug/adapter's capabilities to the main electronics box of the Mobile Connector. The details appear in this CleanTechnica article. There's also a YouTube video that shows the teardown of one of these adapters:
Thus, tearing down a plug/adapter and replacing a resistor won't do what @John Rogers wants. At best, the chip would have to be replaced or reprogrammed. Whether this would be safe is another matter -- the wiring in a plug/adapter designed for 15A might not take a 32A load.

There are third parties that make plugs/adapters beyond those that Tesla offers. EVSEAdapters, in particular, offers a variety of plugs/adapters for Tesla's Gen2 Mobile Connector, as well as adapters designed to cross international electrical standards. I have no idea if any of these would be useful to @John Rogers.
 
That's true of the older Gen1 Mobile Connectors, but the Gen2 Mobile Connectors shipped with the Model 3 (and current-production Ss and Xs) uses a small chip in the plug/adapter to communicate the plug/adapter's capabilities to the main electronics box of the Mobile Connector. The details appear in this CleanTechnica article. There's also a YouTube video that shows the teardown of one of these adapters:
Oh yes, thank you. I had forgotten that Tesla decided to make it all fancy with a computer chip. Where's the fun in that?
 
Although the NEMA 10-50 wiring configuration would suit Australian wiring, I resisted the temptation to buy a NEMA 10-50 adapter and file the pins on the plug to suit Australian outlets. The resulting plug, if it fitted, would approximate an Australian 20 amp plug, but drawing 32 amps. The better part of me opted for a more elegant solution by asking EVSE Adapters to make up an adapter to plug into the Tesla Mobile Connector with an Australian 3 pin 32 amp plug on the other end. They will do so, including delivery to Australia, for $US85. The local Tesla service centre confirmed that they only sell 10 amp and 15 amp adapters in Australia.