ChargePoint - vehicle drawing more current

[mknoebel]

I was charging my Model 3 today and got this message:

The station at which your vehicle is charging has detected that your Vehicle is drawing more current than the station's rating, and has suspended charging to prevent the circuit breaker from tripping. This typically indicates an issue with configuration of the vehicle or an issue with the battery management system on the vehicle. Please contact the manufacturer of the vehicle if you receive this notification again.

Is there some setting I should change for this charger or is this a proble with the charging station?

 

[cwerdna]

You might want to check Plugshare reports on that location and if there are any reports on the Chargepoint web site/app for that location.

Assuming that this is a J1772 (level 2) plug you're using and not a 120 volt plug (found under the corrugated metal door of some older single handle stations), see Basics of SAE J1772 : Support. Normally, a J1772 EVSE emits a pilot signal w/the appropriate duty cycle to tell the car how many amps it can draw at max, typically 30 amps on a Chargepoint station (as long as it's not a CT-4000 w/shared setup and only a single 40 amp feed). The connected vehicle is supposed to comply and draw no more than that.

So, it's either a bug on the car side or a config prob w/the station. If the 3 has some ability to turn down the charging speed (Model S does), that might help, but that should be the exception. You normally should NEVER need to do that. The pilot signal emitted by the station is supposed to take care of that.

(Long range 3 has a 48 amp on-board charger and can draw up to 48 amps if the pilot emitted by the station allows for that. Also, Tesla wall and mobile connectors are J1772 behind the scenes and also emit pilot signals for the same reason.)

 

[mknoebel]

Thanks. And yes, it was a J1772.

 

[swaltner]

This error sounds like (making up numbers) the EVSE says the car can draw 32 amps, but has detected that the car is drawing 40 amps. It shuts itself down to protect itself from what it thinks is a misbehaving vehicle. There are several potential issues here, with no easy way that you as a user could test.

• The EVSE could be sending out the wrong duty cycle on the pilot signal. It may think it’s sending out the signal for 32, but the electronics are incorrectly calibrated and it’s actually telling the car a higher current is safe to draw. To test this, you would need an oscilloscope or an EVSE tester that would decode the signal on the pilot line.
• The EVSE could be measuring the current being drawn incorrectly. It might be reading 40 amps when the car is really drawing 32 amps. You’d need to open he EVSE and put an ammeter around one of the hot wires to. Erich this.
• The car might be messed up, thinking it’s drawing 32 amps, but is really drawing 40 amps. Again, your need to get inside the EVSE and measure the current with another ammeter to verify.

None of these are things you should be doing with someone else’s equipment.

As mentioned earlier in the thread, leave a note on Plugshare and possibly contact the property owner directly. It would be convenient to offer your car for testing purposes when the property owner has an electrician on-site to figure out what’s wrong, likely doing at least the last two checks that I mention, which are really different aspects of the same test. They may not be able to easily test the first item since it requires specialized equipment.

 

[mknoebel]

Very helpful. Thank you.