Charge Rate Reduced - Model 3 SR+

[sandals99]

Hello all,

I have been charging my M3 at home for the since it was new on a HPWC for the last 16 months. The HPWC is on a 40am breaker that was installed into a new home. I've never had a charging issue and i always set the "depart time" in the charging settings and the car is always completely charged to the desired percentage and ready to go in the mornings. This past week for two days in a row, it said the charge was complete but it didn't charge to the desired percentage, which is very strange so I have made a service appt. Then this morning the same thing happened but this time I got an error message that said "charge rate reduced". It normally charges at 32a but was showing 16a. It said to unplug and reconnect, which i tried, but no luck.

Has anyone else experienced this? Any suggestions?

thanks,

 

[RiverBrick]

The charge rate reduced could be due to dust or other contaminates in the charge port or the pistol. There also are many other possible reasons.

 

[Lon12]

Can you try your Mobile Connector on a 240 volt outlet and see if you still have issues?

 

[sandals99]

That's a good idea. Need to find a 240 volt to try it on. I also read on another post that it could be the power conversion system:
Charge Speed Reduced, unplug and try again

 

[Casmium]

Have you tried blowing out the charge port and charging connector with some compressed air(not sure if this is the recommended way to clean it out), or at least looked inside to make sure there isn't dirt or a crushed spider in there, I've had it happen when using some public chargers and usually find that the connector is full of dirt from someone dropping it on the ground.

 

[VancityTM3]

I’ve had this exact issue the past few months. When I’m charging at home, I sometimes would get the full 30 amps but other time it would only draw 16/30. Had a service appointment lined up. Before the service I got a text from SC saying they run some remote diagnostics and everything is working fine and the reduce charging rate is due to a software bug. The issue will be addressed in an upcoming firmware update but did not give an ETA of when that would be.

 

[sandals99]

Thanks, I'll try checking the connector when I get home and will spray it out with compressed air.

 

[sandals99]

I’ve had this exact issue the past few months. When I’m charging at home, I sometimes would get the full 30 amps but other time it would only draw 16/30. Had a service appointment lined up. Before the service I got a text from SC saying they run some remote diagnostics and everything is working fine and the reduce charging rate is due to a software bug. The issue will be addressed in an upcoming firmware update but did not give an ETA of when that would be.

Keep me posted, hope it's not a bug fix that we have to wait a long time for. thanks

 

[TheRFMan]

There are 3 or 4 threads about this in the M3 battery/charging forum. consensus is that a recent software update made the charging system more susceptible to interpreting noise on the AC line as a bad electrical connection.

 

[Casmium]

You can try reducing the current to something like 27 instead of the 32 and see if that helps, 27 is better than 16 and might now cause as much of a voltage drop

 

[sandals99]

Thanks for the tips everyone. I just had my appointment canceled by Tesla service and they sent a note which is similar to what VancityTM3 reported above. Its an issue that is impacting AC charging and they hope to have it resolved in a future firmware upgrade.

 

[4point9]

Same. Had my appointment cancelled stating this is a firmware bug. I even stopped by my local Service Center - who had a technician check the logs - same conclusion. No ETA on when the firmware will be available, but this is the reply I got from mobile service.

"We have spoken to engineering and they have determined the issue that is occurring with charging is related to a known firmware bug. They are diligently working on a solution and will update your vehicle with a firmware revision as soon as its ready. This is a high priority and should be resolved shortly. As a technician is not required we will close this request, however your vehicle has been flagged to require the firmware fix when ready. Thank you for your patience"
​

Posters in other threads have mentioned being told by SC that the issue is around over sensitivity in power quality measurements as other posters here have also noted.

I got firmware update 2020.36.15 this morning, but it did not resolve the problem.

Searching other threads on this topic from several months ago often mentioned replacing the Power Conversion System for cars with the same symptoms. More recently the response is to wait for firmware. I was told in a chat with Mobile Service that several cars are all showing the same logs and symptoms. I hope it doesn't take too long for the firmware fix.

 

[VancityTM3]

Got a new update on Oct 1 and have not had any issues with charging since (I’ve charged 4 times). Still a small sample size but normally it would have failed at least half the time. Hopefully it’s fixed, though no mention of it in the release notes. I’m currently running 2020.36.16.

 

[Nhawk]

36.16 and 40.4 both have reduced rate @32A for me on P3D+. Both at home and at Tesla's HPWC

 

[JD-TX-44]

40.4 for my X is having this new to me issue.

 

[sandals99]

I think mine's been resolved like VancityTM3. It's been working well for a few days now.

 

[4point9]

2020.36.15, and later .16 did not resolve the AC charge limit of 32 amps for me. Tesla Engineering diagnosed my particular case as requiring a new PCS. They did say >99% were of these were firmware related though. Car is back from service with new PCS and PCS Fuse - now charging at 48 amps again!