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AC Charging not working - draws 0 amps

Vol16

Member
Jan 21, 2018
86
127
Cincinnati
So yesterday I got a notification about 20 minutes after plugging in my Model 3 that charging was interrupted. Odd - but has happened once or twice before. I tried to start charging from the app to no avail.

This morning I went out to see what was going on, after re-inserting the cable I noticed the car was not pulling any amps, but was showing voltage. It continued to draw 0 amps for about 10 minutes then I got another charging interrupted notification. UMC and car not showing any errors or lights.

After work today, I dropped by a level 2 charger by my house to rule out the UMC going bad. Sure enough I plug it in and again - 0 amps but showing voltage. I then headed to a supercharger and it worked perfectly.

Do I have a bad on board charger? Any other tips or tricks to try? I have tried powering off the car and a hard reset.

Attached is a pic of what the car does when I plug it into AC charging before it stops “charging” altogether.
C41DB915-CACE-4EB9-9D0E-66749780FE5B.png
 

Schulmann

Member
Nov 27, 2020
25
26
Toronto
Reboot both car and charger.
That s the firts step and usually works.
if you have a Gen 3 Tesla charger log into the web interface and validate the settings.
 

Sophias_dad

Supporting Member
Jul 29, 2018
1,045
947
Massachusetts
The onboard charging equipment(AC->DC converter) might be buggered. If a reboot doesn't work, try a supercharger(which bypasses much of the onboard circuitry because its already DC). At least that'll get you usable mileage and an 'ongoing' solution until you can get it to a servicecenter. If its really the AC->DC converter, that's unlikely to be fixed by a ranger.
 

Vol16

Member
Jan 21, 2018
86
127
Cincinnati
The onboard charging equipment(AC->DC converter) might be buggered. If a reboot doesn't work, try a supercharger(which bypasses much of the onboard circuitry because its already DC). At least that'll get you usable mileage and an 'ongoing' solution until you can get it to a servicecenter. If its really the AC->DC converter, that's unlikely to be fixed by a ranger.
Supercharging works so definitely something to do with the AC to DC system / onboard charger.
 

Rocky_H

Well-Known Member
Feb 19, 2015
6,106
7,084
Boise, ID
No, no, no. Nothing wrong with the charging equipment or onboard charger, etc. Nothing is wrong at all, actually. This is working as intended.

See that blue section at the top of your battery? That tells you what is going on. The battery is so cold that it is not allowing charging to begin yet, since that would be extremely damaging to the battery. So it is drawing energy from the charging station only to run the internal battery heating systems, but that will still show "0 amps" as far as what is being used for charging for the time being. (Or related issue--it's using up all the station's energy just for heating at first and can't divert energy to charging yet.)

If you would have been patient and waited another 15-20 minutes (maybe longer?), the battery would have warmed up enough that you probably would have seen that blue bar start to go away, and you would have started to see some small number of amps show up on the screen that was finally being used for charging.

The Supercharging thing was a bit misleading because it kind of introduced another variable or two. The car got to do more preheating on the way to the Supercharger, and it was warm enough that it could begin some charging when you got there. And also, the public charging station probably was low enough power that it was using up all it had just for heating at first, and didn't actually have any power left over to run any charging yet until it warmed up some. The Supercharger has a lot more, so it can do heating while also having extra to do some slower charging at first.
 

Vol16

Member
Jan 21, 2018
86
127
Cincinnati
No, no, no. Nothing wrong with the charging equipment or onboard charger, etc. Nothing is wrong at all, actually. This is working as intended.

See that blue section at the top of your battery? That tells you what is going on. The battery is so cold that it is not allowing charging to begin yet, since that would be extremely damaging to the battery. So it is drawing energy from the charging station only to run the internal battery heating systems, but that will still show "0 amps" as far as what is being used for charging for the time being. (Or related issue--it's using up all the station's energy just for heating at first and can't divert energy to charging yet.)

If you would have been patient and waited another 15-20 minutes (maybe longer?), the battery would have warmed up enough that you probably would have seen that blue bar start to go away, and you would have started to see some small number of amps show up on the screen that was finally being used for charging.

The Supercharging thing was a bit misleading because it kind of introduced another variable or two. The car got to do more preheating on the way to the Supercharger, and it was warm enough that it could begin some charging when you got there. And also, the public charging station probably was low enough power that it was using up all it had just for heating at first, and didn't actually have any power left over to run any charging yet until it warmed up some. The Supercharger has a lot more, so it can do heating while also having extra to do some slower charging at first.

Hey Rocky
Thanks for the reply. However, this is definitely not normal behavior. I have had the car for 2 years and have had no issues charging in much much colder temps on level 2 and at my home on 24amps as in the picture.
As far as patience, I actually left the charger plugged in for more than a day but the issue is the car itself stops charging after 15-20 mins and never restarts, it is not me removing the cable. Once stopped it does not restart from the app. Also, I tried charging again after returning from supercharging and driving around town but still 0 amps on a warm battery.
I’ve made a service appointment for Wednesday, they’ve already reached out and said this is odd behavior.
 
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Reactions: Rocky_H

MorrisonHiker

S 100D 2021.4.15
Mar 8, 2015
9,567
8,749
Colorado
What firmware are you on? Do you have more than on wall connector?

We had something similar happen on a Model S last night and this morning. I tried starting charging manually but it would never start. The volts were jumping all around from 0 to 120 to 245 and back while amps always stayed at 0. I could see from the security camera that the wall connector light kept restarting. I went out this morning and heard the wall connector would click whenever the light started over. I tried one of the other networked wall connectors and had the same issue. I then lowered the amps down to 16 and the car started charging. It did show 0 mph for a while since the battery was cold (but not as cold as OP and no blue showing in the app). I was beginning to think there might be an issue with the onboard charger but then we stopped charging the Y. I was then able to charge at 40+ amps on the S without any issue. Now I'm wondering if there might be an issue with load balancing on the wall connectors. It's worked great for over two years but I did just install an update on the S a couple days back.

Anybody know how to check the firmware version on gen2 wall connectors? I know their firmware can get updated via the car but don't know how to check it.
 

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