220 50amp only Charging 4mph

New owner of a model x here. The charging station at our house is only charging at 4mph. It is a 220 50 amp breaker so we are just confused as to why. It was professionally installed and they have been her again just to double check their work. Is there something else to be done to get the full 30 to 40 MPH charge?


  • Did the installer configure the wall connector to 40A (80% of 50A) ?
  • Also, check the car so its not set to an amp less than 40A.
  • What does the charge display on the car say? It will list the voltage, and the amperage. The amperage will be two numbers separated by a slash it should say 40/40. If the second number is lower than 40 (like 12) the connector is not configured correctly.

    Next, what is the state of charge of the car? If it is very high >96% then the charge will be normally be very slow.

    Lastly, an X on a 50amp breaker will only charge at about 27mph, not 30-40.
  • @david - It wasn't very clear. Do you have the HPWC or you are using a NEMA 14-50 receptacle and the Mobile Connector that came with the car?

    In addition to other items others suggested above, check the voltage as displayed in the car. It should be around 240v. If it shows 120v - something is wired wrong and you'll get only half the power.
  • I'll add one more comment. If you are checking the charging rate when the vehicle is nearly fully charged, the rate significantly slows down as it reaches the designated charging limit.
  • Had it previously been charging at 40 Amps? When it is charging at 4mph, what do the display lights on the charger look like? If the top light is flashing red while the others are streaming green, you have a known defect in the cord of the Gen 3 charger. There was a bad batch of them that went out. They work for a few weeks then signal that there is an overheating issue even though there’s not. This cuts the charge rate to prevent damage from the phantom overheating. Call Tesla Charging and tell them you have the overheating issue. They’ll send out a new unit. Just takes 4 screws to swap out.
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