Wall Connector Question

Wall Connector Question

Hey good morning Everyone,

I have the Tesla Wall Connector installed at my home on a 100 amp breaker using 3 gauge wire.

When I plugged in an older Model S (not sure of the year, maybe 2016?) that I had as a loaner car, the car only allows up to a maximum of 40 amps on the display when plugged in. When I plug in the current loaner I have (2018 or 2019 Model 3 Performance), that screen shows a maximum of 48 amps.

I'm not very knowledgeable about these electrical things like this but I have 2 questions:

1) Why would the 2 cars have a different maximum amp amount?

2) I thought having a 100 amp breaker would allow the car to charge at a much faster rate/have higher max amp amount than 40 or 48. Is that not the case?

Thanks so much in advance!


jordanrichard | August 5, 2019

You could have a 300 amp breaker, but the car will only draw what the onboard charger is designed for. That is what you were seeing with those loaners. I forget when exactly it was but Tesla did change the onboard chargers. Originally the car came with a single 10kw/40 amp charger that would get one a 29 MPH charging rate. Optional was an additional onboard charger, but to take advantage of it, you would also then need the HPWC which would be connected to a 100 amp circuit and get you a charging rate of 58-60 MPH. Again as I said, at a point Tesla dropped offering a second onboard charger and instead increased the standard onboard charger to 48 amps and offered a 72 (I believe) onboard charger.

Techy James | August 5, 2019

@herrmdogg the Wall Connector has a max rating of 60AMP. The benefit of have 100AMP breaker over 60AMP breaker would be if you have 2 or more Wall Connectors connected to the circuit they could share in the capacity and each get a higher charge per hour.
Regardless of the Breaker, each car has it's max charge rate. If the older Model S was a smaller battery it could also have had a lower max charge rate.
I will use my Model 3 as an example. I have the LR (Long Range) version with the larger battery so I can charge at a max of 48AMP. If I plugged in say a Model 3 SR+ (Standard Range) version then that car has a max charge rate of 32AMP due to the smaller battery.

herrmdogg | August 5, 2019

Thanks for the explanations guys!

So the short version is basically that, with the Wall Connector, I won't get above 48 amps on my 2019 Model 3 Performance, is that correct to say?

Thanks again!

reed_lewis | August 5, 2019

@Techy James - The Tesla wall connector can deliver up to 80 Amps of power depending on how the internal switches are set. But it is up to the car to determine how much power it can accept. If the wall connector can put out 80 amps, but the car will only accept 40 amps, then 40 amps is how much power will go into the car.

Older Model S/X had either a single or dual charger. It was either 40 or 80 amps of power that could be accepted. Newer S/X had either a 48 or 72 amp charger, and current S/X only have a 48 Amp charger. | August 5, 2019

@reed_lewis great explanation. I haven’t heard a better, more accurate description in recent memory. Good to see correct info. Thanks.

Techy James | August 6, 2019

@herrmdogg You are correct in that the 48 Amp is the Max that the Model 3 (Performance, Dual Motor, and LR RWD) supports.

jimglas | August 12, 2019

multply is a bot, please flag

reed_lewis | August 14, 2019

@herrmdogg - Yes. the highest amount of power you will get on any new Tesla is 48 Amps.