Gen 3 Wall Connector current decrease? Anyone else seeing this?

[btenison]

I've had the wall connector connected (by an Electrician) to a 60Amp circuit for almost a year. It has supplied 48Amps of current to the car without fail until the last couple of months. It seems that, when I have the car charging with a Max setting of 48 Amps, the current drawn by the car is 41 Amps. If I decrease the current limit to 41 amps, the car only draws 38 amps. Seems to be linear down to 32 amps (ish) and then the max meets the current draw into the car.

Is anyone else experiencing this? I have a service request in for another issue (passenger seat issue) and added the comment to the communications to the service center but haven't received a response. Just wondering if this is a firmware issue, or something more concerning.

Thanks for any info. I searched around and didn't find this exact issue. I do see the issues with the max current being a multiple of 16 A, but this seems a bit odd when compared to those issues.

Bruce

 

[jjrandorin]

I have seen some threads where people changing the amp settings in the app introduce some "wonkiness" to charging. The remedy I saw for that was to turn up the charging amps in the car if possible, and not change it in the app.

Have you tried turning it back up in the car and seeing if it sticks there?

 

[btenison]

I appreciate the help with this one! Unfortunately, I've tried that too. Tried making the change in the car has the same behavior as making the change in the app. I doubt it's the issue, but I think I'll change my Tesla credentials and hopefully deauth all the things I have connected. Maybe eliminate the possibility of a third part app doing something weird.

 

[AlanSubie4Life]

I do see the issues with the max current being a multiple of 16 A, but this seems a bit odd when compared to those issues.

Might be related to that. Could be a soft failure of part of the PCS, who knows - signature may have changed with software updates. Charging equipment doesn’t seem that likely but certainly possible.

Check the voltage the car sees at each of the current settings (after it has ramped and warmed up) to give a bit more info here on whether there could be an issue with the wall connector/resistance. Certainly wouldn’t rule that out either without more info.

Don’t give up on hassling Tesla about it and report back what they find!

 

[btenison]

Might be related to that. Could be a soft failure of part of the PCS, who knows - signature may have changed with software updates. Charging equipment doesn’t seem that likely but certainly possible.

Check the voltage the car sees at each of the current settings (after it has ramped and warmed up) to give a bit more info here on whether there could be an issue with the wall connector/resistance. Certainly wouldn’t rule that out either without more info.

Don’t give up on hassling Tesla about it and report back what they find!

I'll go back and check the voltage to see if it sags at the higher current limits in a bit. I just did the whole password reset thing and will give it some testing shortly. I really appreciate all the input!!

 

[btenison]

Using the measurements below, it looks like the maximum resistance I would see is about 0.3 Ohms. Unless I'm missing something here, I don't think it's the wiring or connections. Please feel free to correct me if I'm wrong. The car is currently upgrading to 2022.16.2, so I'll check it again then.

Oh and the Tesla password change had no effect on the issue... Was worth a shot...

May be time to hit up Tesla service again :-/

Max Current Limit	Voltage	Current Draw
48	238	41
47	238	40
46	238	39
45	239	39
44	238	38
43	238	37
42	238	37
41	238	36
40	238	35
39	238	35
38	239	34
37	239	34
36	240	33
35	240	32
34	240	31
33	240	31
32	240	30
31	241	30
30	240	29
29	241	28
28	242	27
27	242	27

 

[davewill]

For completeness sake, you should test at another EVSE, preferably one that has 48a capacity like at the service center. Just to narrow down between the car and the wall connector.

 

[btenison]

For completeness sake, you should test at another EVSE, preferably one that has 48a capacity like at the service center. Just to narrow down between the car and the wall connector.

Good idea... I'll have to find a private one to borrow as, since I live in Alabama, it would require a trip to Georgia or Tennessee... But that's another soapbox of mine.

 

[rrolsbe]

Using the measurements below, it looks like the maximum resistance I would see is about 0.3 Ohms. Unless I'm missing something here, I don't think it's the wiring or connections. Please feel free to correct me if I'm wrong. The car is currently upgrading to 2022.16.2, so I'll check it again then.

Oh and the Tesla password change had no effect on the issue... Was worth a shot...

May be time to hit up Tesla service again :-/

Max Current Limit	Voltage	Current Draw
48	238	41
47	238	40
46	238	39
45	239	39
44	238	38
43	238	37
42	238	37
41	238	36
40	238	35
39	238	35
38	239	34
37	239	34
36	240	33
35	240	32
34	240	31
33	240	31
32	240	30
31	241	30
30	240	29
29	241	28
28	242	27
27	242	27

What was the voltage when it first started to ramp up? At my house I see about a 10V drop from no load to 48A; however, about 4V of that is a drop at the service panel. Not sure if this 4V drop on the power provider side is common or not?

 

[btenison]

According to the API (completely disconnected), it's 238.2v (currently). This is the normal average for my home. In addition, we have one of those Ting home power monitor things and it hasn't seen any dips in the power (within a standard band):
{
"config_status": 5,
"contactor_closed": false,
"currentA_a": 0.0,
"currentB_a": 0.0,
"currentC_a": 0.0,
"currentN_a": 0.0,
"current_alerts": [],
"evse_state": 1,
"grid_hz": 59.9,
"grid_v": 238.2,
"handle_temp_c": 23.7,
"input_thermopile_uv": -131,
"mcu_temp_c": 30.8,
"pcba_temp_c": 26.1,
"pilot_high_v": 12.0,
"pilot_low_v": 12.0,
"prox_v": 0.0,
"relay_coil_v": 12.0,
"session_energy_wh": 11321.2,
"session_s": 0,
"uptime_s": 128002,
"vehicle_connected": false,
"vehicle_current_a": 0.0,
"voltageA_v": 2.1,
"voltageB_v": 2.1,
"voltageC_v": 2.1
}

I may log the JSON for all of this for an entire charging session to check the temps as well... Hmmm

 

[btenison]

Contacted Wall Connector Support chat via the website. The checked my car and wall connector. The wall connector is fine but the car is throwing an alert related to the on board chargers. Guess it’s service appointment modification time. :-/

 

[Gauss Guzzler]

It looks like you're reading the current from a deeper source than the usual car screen or Tesla app. Perhaps you're reading the current going into the battery which may be different from the current going thru the charger as the car often uses some current for non-charging purposes. What does it say on the car's screen (or app)? Does it really say "238V 41/48A"?

 

[btenison]

It looks like you're reading the current from a deeper source than the usual car screen or Tesla app. Perhaps you're reading the current going into the battery which may be different from the current going thru the charger as the car often uses some current for non-charging purposes. What does it say on the car's screen (or app)? Does it really say "238V 41/48A"?

Actually, the table above was from the car's screen data. I have (since then) written a groovy app to read the Json from the wall connector API and log the data into a database table to get the current/voltage measurements directly from the connector. It matches what I'm seeing in the car display.

According to wall connector support, they say it's the car's charger(s) that are at fault.

 

[AlanSubie4Life]

According to wall connector support, they say it's the car's charger(s) that are at fault.

Yes, if it were the wall connector, I would kind of expect it to limit the maximum current available (since that seems like it would be a good way to protect it if it were marginal in some way), but that is not what is happening here.

I guess we will see! Thanks for the updates!