Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

14-50 home charging issues

PeterNFS

Member
Jan 14, 2020
8
2
Chicago
HI - wondering if others had similar issues and what they did to fix it:

Got my Model 3 in March with the Gen 2 mobile connector and had a NEMA 14-50 installed at home. When charging at the full 32amp current, often after 10-15min it "craps" out and just stops charging. only message I get is "Charging has stopped" and it's not anywhere close to the 80%. When I set the current to 24amp it usually always completes the charging process to the set target charge. No one so far could definitively tell me what is going on. I was at a Tesla Service center and they plugged it into their 14-50 but could not reproduce the issue, when I go to level 2 public chargers also no problems as well as no problems at superchargers. so all that points to an issue in my house.

One thing I noticed is that during weekdays my voltage on the screen shows anywhere between 242 - 248 volt and sooner or later the charge is going to interrupt again. on weekends during the lockdown I noticed that the voltage is running more between 236 - 240 V max and on those days, the charge goes through for hours with no issues. Does anyone know what the "tolerance" of the car is regarding the voltage and has anyone had the issue with voltage at the higher end in their house and has some mitigations put in place? My electrician is running out of ideas and a Tesla certified electrician did not got me much further either.
 

1965Falcon

Supporting Member
Oct 10, 2019
108
193
Vancouver, WA
If you know anyone with a mobile connector you could try, I'd try and narrow it down that it's not a problem with the mobile connector. Maybe the service center could give you a loaner for a day. As for tolerance, I think 5% is what manufacturers need to design too and what is normal variance. That would be a range of 228 to 252. You might be getting spikes up above that if you are seeing 248.. I'd try and find something that could log your voltage (doesn't need to be on the 240, you can log it on a standard 120 and see if it's staying in spec... just move it to a few different outlets so you see what's happening on both legs). Maybe your electrician has something that can do that.
 

Sklith

Member
Jul 23, 2019
218
181
GA
How long ago did you have your electrician install the 14-50 receptacle? Might want to let them know you're having problems with pulling 32 amps from it.
 

jdcollins5

Member
Aug 14, 2018
758
491
Wilmington, NC
Have an electrician check your breaker and receptacle wire connections. A loose connection can cause heating and cause the charger to shut down. That could also explain why 24A is not a problem but 32A is.
 
  • Like
Reactions: PeterNFS

brkaus

Well-Known Member
Jul 8, 2014
7,696
6,227
Austin, TX
Check everywhere for heat. Is the plug into the wall hot? Is the plug into the car hot?

If nothing super hot, then borrow a UMC and try your home again.
 
  • Like
Reactions: PeterNFS

Sophias_dad

Supporting Member
Jul 29, 2018
1,008
873
Massachusetts
My bet is on a bad UMC or bad plug/outlet.

The 3 is extremely tolerant of voltage. I've had mine charge successfully at 183(J1772) and 286V(HPWC). I'm not sure if the UMC has extra logic, but I doubt it.

I'm sure its less tolerant of voltage drops after starting to charge at a given voltage, because it'll potentially interpret that as a wiring/outlet issue. By 'less' I mean it will undoubtedly ramp up the current while watching the voltage go down. If it sees voltage dropping at an unusual rate, it will backoff or even stop charging. If instead it goes up to its alotted maximum current without an unusual drop and then sees 'typical' rates of line voltage fluctuation, it'll keep charging.
 
  • Informative
Reactions: jjrandorin

animorph

Active Member
Apr 1, 2016
2,132
1,527
Scottsdale, AZ
I believe the charger will reduce the current if it sees a voltage drop (before charge starts vs during charging) of around 10V. The charging voltage level is usually not an issue (I frequently run 250V+), but a large voltage drop as the charger starts up is indicative of something wrong with the wiring or connections.

It could also happen if you or your neighbors add a big load while the car is charging. 242V to 246V is a large swing if the charging amperage is holding constant. I'd check the voltage at the breaker box during charging (actually a volt meter at a socket on a little used circuit in your house would work) and see how much the voltage varies there. Ideally it won't. A large voltage drop or variation at the breaker box could indicate the line feeding your house is a little small, or your local transformer is being pushed too hard. I think both problems have shown up on the forum, though loose connections are more frequent.
 

PeterNFS

Member
Jan 14, 2020
8
2
Chicago
How long ago did you have your electrician install the 14-50 receptacle? Might want to let them know you're having problems with pulling 32 amps from it.
was installed in March when I got the car, the electrician does not know - he even went out of his way to talk to the Tesla technical folks but did not get much further other than that they pointed to potential issues with the grid fluctuations.
 

PeterNFS

Member
Jan 14, 2020
8
2
Chicago
I believe the charger will reduce the current if it sees a voltage drop (before charge starts vs during charging) of around 10V. The charging voltage level is usually not an issue (I frequently run 250V+), but a large voltage drop as the charger starts up is indicative of something wrong with the wiring or connections.

It could also happen if you or your neighbors add a big load while the car is charging. 242V to 246V is a large swing if the charging amperage is holding constant. I'd check the voltage at the breaker box during charging (actually a volt meter at a socket on a little used circuit in your house would work) and see how much the voltage varies there. Ideally it won't. A large voltage drop or variation at the breaker box could indicate the line feeding your house is a little small, or your local transformer is being pushed too hard. I think both problems have shown up on the forum, though loose connections are more frequent.

Thanks - the issue seems to happen when the voltage runs 242-248, up and down within that range. that's usually on weekdays and then I have the issues. On the weekend days I've tested, the voltage runs lower at around 236-240v max and on these days charging at the 32amp current is no issues. Just what I observed from looking at the display, don't have any logs, looking to get a TeslaMate setup but not yet sure if that would tell me what I need to know.
 

Sklith

Member
Jul 23, 2019
218
181
GA
I think Teslamate will absolutely help! Here's my charge last night, you can see the voltage go from 241-245.

upload_2020-7-9_12-53-49.png
 
  • Like
Reactions: PeterNFS

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top