Summer Heat Affecting 2022 Model S Home Charging?

[Mr. Jetson]

I have a NEMA 14-30 plug installed in a home with an older and limited amp electrical panel which is almost maxed out. My MS would usually charge with the corresponding Tesla charging adapter at the expected 80% (24 amps). Over the summer, I've noticed on the iPhone app that the charge may start at 24 amps but soon reduce to 12 amps for the duration. I am wondering why this is occuring and whether the summer heat is the reason since it has regularly been 110-115+ degrees during the day. I do charge overnight, but it is still in the high 90's with retained heat in the garage likely higher. I do not have any overheating warning.

The electric company (Southern California Edison) has no knowledge of a reduction in output but it may be that the customer service people simply aren't informed. My electrician suggested coming out to check for a loose connection. I will schedule for a checkup, but I suspect that this is not the cause.

Maybe the amp reduction is unrelated to the excessive heat?

Any thoughts?

 

[DerbyDave]

On my 2020 using the android app, the amps are rarely displayed correctly in the app initially, then they generally change to the correct value within a minute. I wouldn't trust the app's accuracy, check in the car to verify. Also, you can check the Tesla Wall Connector 3 to verify electrical info while on the same network as the wall connector. Find the IP address of your wall connector, and enter the following minus the <> as the URL in a any browser:
<wall connector IP address>/api/1/vitals

The following info can be obtained:
{"contactor_closed":false,"vehicle_connected":false,"session_s":0,"grid_v":241.5,"grid_hz":59.953,"vehicle_current_a":0.0,"currentA_a":0.0,"currentB_a":0.0,"currentC_a":0.0,"currentN_a":0.0,"voltageA_v":2.1,"voltageB_v":2.1,"voltageC_v":2.1,"relay_coil_v":11.9,"pcba_temp_c":29.3,"handle_temp_c":27.3,"mcu_temp_c":35.4,"uptime_s":4698337,"input_thermopile_uv":-144,"prox_v":0.0,"pilot_high_v":11.8,"pilot_low_v":11.8,"session_energy_wh":3151.200,"config_status":5,"evse_state":1,"current_alerts":[]}

 

[Mr. Jetson]

On my 2020 using the android app, the amps are rarely displayed correctly in the app initially, then they generally change to the correct value within a minute. I wouldn't trust the app's accuracy, check in the car to verify. Also, you can check the Tesla Wall Connector 3 to verify electrical info while on the same network as the wall connector. Find the IP address of your wall connector, and enter the following minus the <> as the URL in a any browser:
<wall connector IP address>/api/1/vitals

The following info can be obtained:
{"contactor_closed":false,"vehicle_connected":false,"session_s":0,"grid_v":241.5,"grid_hz":59.953,"vehicle_current_a":0.0,"currentA_a":0.0,"currentB_a":0.0,"currentC_a":0.0,"currentN_a":0.0,"voltageA_v":2.1,"voltageB_v":2.1,"voltageC_v":2.1,"relay_coil_v":11.9,"pcba_temp_c":29.3,"handle_temp_c":27.3,"mcu_temp_c":35.4,"uptime_s":4698337,"input_thermopile_uv":-144,"prox_v":0.0,"pilot_high_v":11.8,"pilot_low_v":11.8,"session_energy_wh":3151.200,"config_status":5,"evse_state":1,"current_alerts":[]}

Thanks, @DerbyDave. So does this mean that you don't think that the heat is the issue? The car indictes 12 amps too, corressponding with the app. But I definitely notice that charging is slower than it was, meaning that the 24 amps used to be the norm. I don't know where to find the IP address of the wall connector (BTW, I have a mobile connector directly into a 220 amp plug) and I am not sure what the example info is telling us, but I don't see amp info..

 

[Tronguy]

Um. There have been multiple reports that the TMC has a thermal sensor in the bit that goes into the wall socket. Since power dissipation on potential loose connection goes as current*current*(too much resistance), that's a "square" factor. Dropping the current by lots Saves The Day and keeps the smoke inside of things.

The other thing that TMCs and the car are known to do is if there's a drop in line voltage with increasing current, the car/TMC will drop the current, likewise. I've seen this one on cold, snowy days (no question about heating, here) with a somewhat inadequate "heavy duty" extension cord from Home Depot. As I found out later, the only "heavy duty" thing about those cords is the Heavy Amount of Insulation (not copper) the cords contain. Switching to an extension cord from Harbor Freight that was actually rated for 15A fixed that problem.

Going back to the first issue: A fair number of 240 VAC connectors aren't really rated for multiple insertions and removals. There's been lots of comments about not-quite-ready-for-prime-time NEMA14-50 sockets from the like of Home Depot with (I think) Hubble-brand sockets being better, with tons more surface area on the contacts. I don't know if this translates over to your NEMA14-30, but the cheapie manufacturers always find a way to reduce the metal in such a socket. Passes UL standards; yes: works after 1000 insertions/removals, not so much.

I'd suggest popping the breaker on this socket, hauling it out of the wall, and:

1. Eyeball the heck out of the socket and see if things look pitted/worn/etc.
2. Torque the screws holding the wires down. If you get a half-turn out of any of the screws, well, that may have been your problem.

Some time back, some punter on these forums came up with a low-tech, but usable solution: Pointing a fan at the socket. Which apparently, in his case, cooled things down enough. But I'd investigate that socket, were I you.

 

[Mr. Jetson]

Um. There have been multiple reports that the TMC has a thermal sensor in the bit that goes into the wall socket. Since power dissipation on potential loose connection goes as current*current*(too much resistance), that's a "square" factor. Dropping the current by lots Saves The Day and keeps the smoke inside of things.

The other thing that TMCs and the car are known to do is if there's a drop in line voltage with increasing current, the car/TMC will drop the current, likewise. I've seen this one on cold, snowy days (no question about heating, here) with a somewhat inadequate "heavy duty" extension cord from Home Depot. As I found out later, the only "heavy duty" thing about those cords is the Heavy Amount of Insulation (not copper) the cords contain. Switching to an extension cord from Harbor Freight that was actually rated for 15A fixed that problem.

Going back to the first issue: A fair number of 240 VAC connectors aren't really rated for multiple insertions and removals. There's been lots of comments about not-quite-ready-for-prime-time NEMA14-50 sockets from the like of Home Depot with (I think) Hubble-brand sockets being better, with tons more surface area on the contacts. I don't know if this translates over to your NEMA14-30, but the cheapie manufacturers always find a way to reduce the metal in such a socket. Passes UL standards; yes: works after 1000 insertions/removals, not so much.

I'd suggest popping the breaker on this socket, hauling it out of the wall, and:

1. Eyeball the heck out of the socket and see if things look pitted/worn/etc.
2. Torque the screws holding the wires down. If you get a half-turn out of any of the screws, well, that may have been your problem.

Some time back, some punter on these forums came up with a low-tech, but usable solution: Pointing a fan at the socket. Which apparently, in his case, cooled things down enough. But I'd investigate that socket, were I you.

@Tronguy Thanks for the useful input!

 

[Mr. Jetson]

@DerbyDave: Regarding my note earlier "BTW, I have a mobile connector directly into a 220 amp plug"....I obviously meant a 220v plug into which I have a 14-30 recepticle and which I use with a Tesla mobile adapter. Am I correct that your advice regarding the charger IP address is intended for the alternative Wall Connector (which I am not using)?

 

[DerbyDave]

No, heat could be an issue. The stats listed from the Wall Connector includes amps and temperatures.

grid_v=voltage from wall
vehicle_current_a = amps your car is expecting (what you set)
currentA_a, b, c = add these up for amps the wall connector is supplying
pcba_temp-c = power connector back attachment temperature
handle temp
mcu temp
etc

{"contactor_closed":true,"vehicle_connected":true,"session_s":190,"grid_v":234.4,"grid_hz":59.928,"vehicle_current_a":32.0,"currentA_a":31.4,"currentB_a":0.6,"currentC_a":0.0,"currentN_a":0.0,"voltageA_v":235.8,"voltageB_v":236.0,"voltageC_v":116.1,"relay_coil_v":6.1,"pcba_temp_c":31.3,"handle_temp_c":29.3,"mcu_temp_c":37.3,"uptime_s":4716286,"input_thermopile_uv":-181,"prox_v":1.5,"pilot_high_v":4.7,"pilot_low_v":4.2,"session_energy_wh":51.000,"config_status":5,"evse_state":11,"current_alerts":[]}

 

[DerbyDave]

The stats are available for the current model Wall Connector 3 that is connected to your WiFi.

 

[Mr. Jetson]

No, heat could be an issue. The stats listed from the Wall Connector includes amps and temperatures.

grid_v=voltage from wall
vehicle_current_a = amps your car is expecting (what you set)
currentA_a, b, c = add these up for amps the wall connector is supplying
pcba_temp-c = power connector back attachment temperature
handle temp
mcu temp
etc

{"contactor_closed":true,"vehicle_connected":true,"session_s":190,"grid_v":234.4,"grid_hz":59.928,"vehicle_current_a":32.0,"currentA_a":31.4,"currentB_a":0.6,"currentC_a":0.0,"currentN_a":0.0,"voltageA_v":235.8,"voltageB_v":236.0,"voltageC_v":116.1,"relay_coil_v":6.1,"pcba_temp_c":31.3,"handle_temp_c":29.3,"mcu_temp_c":37.3,"uptime_s":4716286,"input_thermopile_uv":-181,"prox_v":1.5,"pilot_high_v":4.7,"pilot_low_v":4.2,"session_energy_wh":51.000,"config_status":5,"evse_state":11,"current_alerts":[]}

Thanks. But I was trying to say that I think you're referring to THE Wall Connector. I don't have one so I don't think I can get to the URL and data ot which yo're referring. Meanwhile, I just noticed a red "T" on the Adapter where the lights usually sequentially light up green from top to bottom of the word Tesla. A Clue about the problem?

 

[Tronguy]

Thanks. But I was trying to say that I think you're referring to THE Wall Connector. I don't have one so I don't think I can get to the URL and data ot which yo're referring. Meanwhile, I just noticed a red "T" on the Adapter where the lights usually sequentially light up green from top to bottom of the word Tesla. A Clue about the problem? View attachment 960753

Yep, that's a TMC, not a TWC, no kidding. My understanding is that there's a temperature sensor in the fat thing plugged into the wall socket.

And, according to the theory of, "Everything breaks eventually", there's no guarantee that any of the cock-a-mamie hypotheses I shoved out the door, above, are correct. People do, occasionally, get a bad TMC. Either new or after a while.

Always fun trying to figure out what actually died.

 

[OlderThanDirt]

Gen 2 UMC owners manual might offer some help. https://www.tesla.com/sites/default...bile_connector_owners_manual_32_amp_en_US.pdf

 

[Mr. Jetson]

Gen 2 UMC owners manual might offer some help. https://www.tesla.com/sites/default...bile_connector_owners_manual_32_amp_en_US.pdf

Yes, it seems to be a problem caused by the extreme local heat. Unplugging and re-plugging both ends seems to have resolved the issue (for now). Thanks to everyone for all the help!

 

[#17Midfielder]

Thanks. But I was trying to say that I think you're referring to THE Wall Connector. I don't have one so I don't think I can get to the URL and data ot which yo're referring. Meanwhile, I just noticed a red "T" on the Adapter where the lights usually sequentially light up green from top to bottom of the word Tesla. A Clue about the problem? View attachment 960753

So I have this issue here in FL, my plug gets the south facing sun and if I forget to close the garage, the charger goes into a thermal protect mode and lights up the T like yours. It will reduce the charging A down until the temps regulate. I'm going to either move or shade the plug.

 

[itch808]

No problems here in Vegas with a wall charger running at 48a. We were hitting 120F the other week

 

[Exscite]

Thanks. But I was trying to say that I think you're referring to THE Wall Connector. I don't have one so I don't think I can get to the URL and data ot which yo're referring. Meanwhile, I just noticed a red "T" on the Adapter where the lights usually sequentially light up green from top to bottom of the word Tesla. A Clue about the problem? View attachment 960753

I have been experiencing this slowing charging at home every once in awhile, and there was a message on the Tesla screen saying the wall connector is heating up. Indeed it has. You know the saying "when everything fails consult the manual"? I did. I've checked the Tesla Wall Connector Installation Manual, page 25. Somewhere there it says that the cause may be that the PLUG (see picture on the left) is not plugged in all the way. When I examined it I noticed that indeed it is not plugged in all the way. So, being careful I first disconnected the main 240v, then I unlogged the connector (the PLUG) and plugged it in back forcefully.

Since then, I have had no wall connector heating problem and my Tesla Y is happily charging inside my garage.
I assume that not plugging it all the way in can increase the contacts resistance, thus generating more heat.

Try it, it is very easy.

 

[#17Midfielder]

I just came back to this thread to say the same thing. I reseated the pigtail and it’s back to normal.

 

[Mr. Jetson]

As a reminder of the problem: The Mobile Connector charger was lowering the amp draw of the car whenever the plug would overheat during charging rather than tripping the circuit. The Mobile Connector's top LED light would flash red. (I don't have a GFI installed since it wasn't required until recently in my location, but if it was, the connector and GFI will conflict and trip the GFI.) In that case, the recommended solution seems to be switching to a hard-wired Wall Connector.

So, after a lot of research and discussions with Tesla and a highly skilled electrician company, here is the conclusion: While there are other random factors that could affect the Mobile Connector charger (like it not being completely plugged in or excessive temperatures of 115 plus degrees), the problem of the Mobile Connector overheating the wall plug has to do with the plug being a residential vs industrial type. The Industrial plug is intended for longer durations of use rather than, say, a clothes dryer. Another factor is that the mobile connector is not designed to be constantly removed from the wall. The Hubbell brand is the preferred, quality industrial plug, but is more expensive than the residential type and does have a larger faceplate..

Problem resolved!