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"Charge rate reduced, Unplug and retry" error requires battery replacement

Nix Alba

Member
Aug 15, 2018
14
12
Parker, CO
For some time now I've been limiting my charge rate to 32 amps, even though I have the capability of charging at a full 48 amps. I did this primarily to reduce the spike power demand to my electrical provider.

The other day, I realized that I had forgotten to plug the car in the previous night, and it was fairly low on charge. Before heading out for the day I bumped the charge rate back to 48 amps. Almost immediately, I received the error, "Charge rate reduced, Unplug and retry". After a small bit of testing, I realized that unplugging and retrying did nothing to resolve the problem. A quick search on TMC and the Tesla support forums indicated that Tesla could remote diagnose the problem, so I called Roadside Assistance, and they did just that.

After performing the remote diagnostic, the technician informed me that I needed to take my M3 into the local service center for more thorough troubleshooting. Initially, the appointment date and time was convenient, but my wife had a conflict and couldn't help me drop the car off, so I cancelled the appointment and re-scheduled as a mobile service. A few hours later, I received a text that my car needed its Power Conversion System (PCS) replaced and that could not be done via a mobile service. They rescheduled a new drop-off time.

My wife and I dropped the car off at the appointed time. Two days later I received a text indicating that I would need a full battery replacement, not just a PCS. He said it would take about two weeks to special order to the battery and perform the repair. I asked for a loaner car given the amount of time it was going to take. The next day he had a Model S available for me. (Nice car, very roomy. I find that I prefer my M3).

When I went to collect the loaner car, I asked him more about why my M3's battery needed to be replaced. Had I done something wrong by limiting my charge rate to 32 amps for several months? Was there a problem with my HPWC (gen 3) that could have effected it? He answered, "No," to all my questions. He stated that being able to change charge rates any time and as often as you wanted was a supported feature, and using that feature shouldn't create the conditions necessary to require a battery replacement. He told me that my M3 was the first at the Littleton, CO Service Center to require a full battery replacement.

I was still confused as to why the battery needed to be replaced when I could take it to a SuperCharger and get a full speed charge, just not when I was at home using my HPWC. I may not be conveying his answer correctly, but from what I recall, he said that they couldn't just replace the PCS and retain the battery because they were a mated pair (my phrase, not his. I don't recall his exact words). He said that if this were an out-of-warranty repair, it would cost $16,000. Naturally this concerns me, as I don't want to have to contend with a similar failure and associated repair cost after the car's warranty expires.

My M3 may be the first in the Denver area to require a full battery replacement, but I'm certain I'm not the first ever. If you've had a battery replacement done, did you notice any significant changes afterwards? Have any of you had a PCS replacement without having a full battery replaced?

My M3 is a 2018 with 23,122 miles. At this moment, it is still in the service center waiting for all the parts to arrive.
 

webbah

Active Member
May 22, 2012
1,001
949
Lucerne, Switzerland
For some time now I've been limiting my charge rate to 32 amps, even though I have the capability of charging at a full 48 amps. I did this primarily to reduce the spike power demand to my electrical provider.

The other day, I realized that I had forgotten to plug the car in the previous night, and it was fairly low on charge. Before heading out for the day I bumped the charge rate back to 48 amps. Almost immediately, I received the error, "Charge rate reduced, Unplug and retry". After a small bit of testing, I realized that unplugging and retrying did nothing to resolve the problem. A quick search on TMC and the Tesla support forums indicated that Tesla could remote diagnose the problem, so I called Roadside Assistance, and they did just that.

After performing the remote diagnostic, the technician informed me that I needed to take my M3 into the local service center for more thorough troubleshooting. Initially, the appointment date and time was convenient, but my wife had a conflict and couldn't help me drop the car off, so I cancelled the appointment and re-scheduled as a mobile service. A few hours later, I received a text that my car needed its Power Conversion System (PCS) replaced and that could not be done via a mobile service. They rescheduled a new drop-off time.

My wife and I dropped the car off at the appointed time. Two days later I received a text indicating that I would need a full battery replacement, not just a PCS. He said it would take about two weeks to special order to the battery and perform the repair. I asked for a loaner car given the amount of time it was going to take. The next day he had a Model S available for me. (Nice car, very roomy. I find that I prefer my M3).

When I went to collect the loaner car, I asked him more about why my M3's battery needed to be replaced. Had I done something wrong by limiting my charge rate to 32 amps for several months? Was there a problem with my HPWC (gen 3) that could have effected it? He answered, "No," to all my questions. He stated that being able to change charge rates any time and as often as you wanted was a supported feature, and using that feature shouldn't create the conditions necessary to require a battery replacement. He told me that my M3 was the first at the Littleton, CO Service Center to require a full battery replacement.

I was still confused as to why the battery needed to be replaced when I could take it to a SuperCharger and get a full speed charge, just not when I was at home using my HPWC. I may not be conveying his answer correctly, but from what I recall, he said that they couldn't just replace the PCS and retain the battery because they were a mated pair (my phrase, not his. I don't recall his exact words). He said that if this were an out-of-warranty repair, it would cost $16,000. Naturally this concerns me, as I don't want to have to contend with a similar failure and associated repair cost after the car's warranty expires.

My M3 may be the first in the Denver area to require a full battery replacement, but I'm certain I'm not the first ever. If you've had a battery replacement done, did you notice any significant changes afterwards? Have any of you had a PCS replacement without having a full battery replaced?

My M3 is a 2018 with 23,122 miles. At this moment, it is still in the service center waiting for all the parts to arrive.


Firstly, this sucks and I can relate. Not in my Model 3, but in my previous Roadster I had to have my 3.0 Battery replaced only a few months after install. For such a rare car it took months instead of weeks as the batteries are hand made. For the Model 3 it is true that battery pack, and related electronic systems are an integrated unit. You can see more here in this Model 3 battery video teardown:


I'd be comforted and happy that Tesla is doing what's needed to make things right. Once you get closer to warranty expiration decide if it's time to trade up, etc.
 

Raro

Member
Jul 23, 2020
67
66
Los Angeles
At least the warranty is valid for 8 years, so it's not an expense that anyone would have to face for a while (and it will likely be cheaper by then too).

I might be wrong but im not sure the onboard Charger, AC/DC and the DC/DC converters are a part of the Battery and drive unit warranty. i think those are just covered by the regular new car warranty, there is no specific mention of them in the warranty document under the battery and powertrain section, it just talks about the battery itself and the drive units.
 

ItsNotAboutTheMoney

Well-Known Member
Jul 12, 2012
10,629
7,795
Maine
I might be wrong but im not sure the onboard Charger, AC/DC and the DC/DC converters are a part of the Battery and drive unit warranty. i think those are just covered by the regular new car warranty, there is no specific mention of them in the warranty document under the battery and powertrain section, it just talks about the battery itself and the drive units.

I don't know, but the failed charger in my Volt was replace under warranty well after the normal 3/36k warranty expired.
However, OP is in Colorado, which is only now joining the ZEV program, so the warranty might be different there.
 

Raro

Member
Jul 23, 2020
67
66
Los Angeles
I don't know, but the failed charger in my Volt was replace under warranty well after the normal 3/36k warranty expired.
However, OP is in Colorado, which is only now joining the ZEV program, so the warranty might be different there.

From what I read before buying the car I found the vast majority of people who had documented onboard chargers or DC/DC converters fail after the 4 year warranty ran out had to pay out of pocket even if the battery and drive unit warranty was still valid. it seems Tesla is taking a hard line approach on these issues. basically only covering battery issues.
 

ucmndd

Well-Known Member
Mar 10, 2016
6,678
12,543
California
I might be wrong but im not sure the onboard Charger, AC/DC and the DC/DC converters are a part of the Battery and drive unit warranty. i think those are just covered by the regular new car warranty, there is no specific mention of them in the warranty document under the battery and powertrain section, it just talks about the battery itself and the drive units.
That’s definitely correct. The battery and drive unit warranties cover the battery and the drive unit. Nothing else.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,050
12,109
San Diego
he said that they couldn't just replace the PCS and retain the battery because they were a mated pair (my phrase, not his. I don't recall his exact words)
To the best of my knowledge this is not true. There have been plenty of reports here about PCS replacements without requiring a main battery replacement.

It sounds like your main battery had some other issue, or at least it flagged in their diagnostics (even if there is nothing actually wrong with it).

I hope they get your car put together ok - it's quite involved to replace the main battery! Lots of the interior has to be removed.
 

potpal

Member
Feb 25, 2020
6
4
Burnaby
I've been having a similar issue since August 2020 but mine only charged at 16amp out of the 48amp available with the Tesla Wall Home Charger. Brought it into Tesla service 3 times, called Tesla Home Charging 3 times and 1 visit with mobile service. Home charging even sent me a new Wall Charger which did not fix my issue. At first they though it was PCS but my car would charge at 48amp at the service center, it only happened at my home. Electrician checked out all my circuits, wires and breakers and I was getting full 240v at all the connection points to the Wall Charger. I even had the Mobile Tech plug his Model S in and he was able to charge his car past 16amp. So can't be Wall Charger or my circuits. Mobile technician called me back and they told me a few cars are having this similar issue where the combination of my Power Grid and Car Software is causing the issue. He booked me an appointment a few out to have my issue looked at and hopefully a patch pushed to me car to fix my charging issue. Power Grid and Car Software explanation is a far stretch for me so we'll see when I go in next week for my service center appointment.
 

Sans-gas

Member
May 1, 2019
120
52
NW WA
There are more than 25 reports of M3 and Y’s from 2018-2020 with similar reports of reduced charging ability and failed charging when using AC (no trouble with SC) on this forum. It appears Tesla is aware and is working on a firmware fix.

We’re collectively crossing our fingers it comes soon.
 

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