M3 SR+ failed battery replaced under warranty, with a very used pack

[carbonzhp]

I just received my 2019 M3 sr+ back from Tesla after a failing HV pack displayed BMS code a066 for a few days, then eventually stopped charging. With Teslogic I could see a 30%+ degradation and a large cell voltage min max. Displayed max range was below 180 miles.

The dealership agreed it needed a new battery and I drove the car for a week until it would no longer charge. Dealership said the battery was ordered. My wife brought the car in for me when it would no longer charge and they gave us a 2019 M3 Dual motor as loaner.

Car was out of my hands less than a week before it was ready to pick up. The first thing I checked was Teslogic and the battery is definitely not new and actually quite heavily degraded. Quite disappointing to see such wear after a service like that. Anyone have a different experience?

 

[El joe]

I always wondered how they’d handle that situation. I would’ve though they’d give you a used pack, but something closer to a pack with ten percent or less degradation. That’s rough.

 

[jjrandorin]

There isnt anything in Teslas Warranty that says a battery replacement would be new. Its pretty much the opposite, in fact. They only have to give you a battery with either similar range before it threw the error codes, or with "similar wear".

I could copy / paste the section from the warranty that shows that, but the times I have done that before, some people take it as being argumentative or something, so I will just say you can check what the warranty says if you are so inclined.

I have no idea of that Teslogic information is accurate, but if so, the replacement battery has close to 1/3 the charging cycles. If your car was really low miles or something, you might be able to argue with them about wear. If its the same car you were posting about here a bit over a year ago, you had 55k miles on it last year in august. How many miles now?

 

[nicksp]

What kind of warranty did the replacement battery come with?

 

[DownshiftDre]

Any chance this improves with any below?

1. pack rebalance (charge above 95%)

2. a BMS recalibration (discharge to low SoC and sleep for several hours, then charge to high SoC and sleep several hours)

3. A long drive.

Continue repeatedly.

 

[Eric33432]

I imagine the car just continues its original warranty on the battery. Is there any statistic anyone knows about that says how often a battery fails, apparently pre-maturely, because this seems to be rare, I keep hearing the battery should way outlast the warranty.

 

[carbonzhp]

One concern is definitely restarting a short fuse close to warranty ending. Car has 78k miles and yes the cycles reported are 1/3 of the old pack but 20% degradation does suck. I did search around and read Teslas warranty terms about ‘similar pack health from before the fault’. Seems like a good way for them to do the least work possible

I plan on running the battery health check built into service mode. Running that on the old pack showed 81% health. Current full charge mileage indicated on this pack is ~205 miles which is about what I had previously

 

[davewill]

Any chance this improves with any below?

1. pack rebalance (charge above 95%)

2. a BMS recalibration (discharge to low SoC and sleep for several hours, then charge to high SoC and sleep several hours)

3. A long drive.

Continue repeatedly.

Yeah, I'd definitely hold off judgment until I'd gone through a few discharge/recharge cycles. The numbers might improve after the car's BMS has had some time with it. That said, it does appear that the wear on the new pack is fairly representative of the wear the old pack had.

 

[pipp]

One concern is definitely restarting a short fuse close to warranty ending. Car has 78k miles and yes the cycles reported are 1/3 of the old pack but 20% degradation does suck. I did search around and read Teslas warranty terms about ‘similar pack health from before the fault’. Seems like a good way for them to do the least work possible

I plan on running the battery health check built into service mode. Running that on the old pack showed 81% health. Current full charge mileage indicated on this pack is ~205 miles which is about what I had previously

Do you have any kind of ”feel” for how much of the degradation your original battery underwent was due to the battery simply being a lemon, and how much might have been from keeping it charged too high, running it down too low, etc.? Was it clear from the start that it was going downhill faster than other batteries, or did much of the degradation occur in the last few months? My battery has been very average in terms of degradation so far, but I’m wondering if maybe things can turn around quickly and I could conceivably get a sudden burst of degradation when the car is 3-4 years old.

 

[AAKEE]

I guess the BMS comes ”with” the battery so it should have a clue about the capacity.

For the warranty, the replscemrnt battery should hold at least the capacity ypur batt had ”before the failure”.

The timing for the capacity ”before the failure” can be a interresting discussion.

 

[jjrandorin]

One concern is definitely restarting a short fuse close to warranty ending. Car has 78k miles and yes the cycles reported are 1/3 of the old pack but 20% degradation does suck. I did search around and read Teslas warranty terms about ‘similar pack health from before the fault’. Seems like a good way for them to do the least work possible

I plan on running the battery health check built into service mode. Running that on the old pack showed 81% health. Current full charge mileage indicated on this pack is ~205 miles which is about what I had previously

Yeah I agree with you 100%, it does suck. If that were my car, I would be pretty upset. I would then search around for Teslas warranty information to see "WTF can they even do that?", then see that "yes, they can do that, it sucks #@!$!$#@ but they can do that", then I would be mad, but deal with it (or be mad, decide it was the last straw, then sell the car and get another brand vehicle, one of those two things).

The thing with Tesla is, my experience with individuals within the company has been good, to great. the company itself, however, seems to put roadblocks in employees way when they want to "do the right thing".

Like, in this case, the "Right thing" doesnt have to be a brand new battery, but it really should be a "gently used" one with like no more than 6-7% degradation tops. If they gave you a new battery, or one with just 2-3% degradation, this thread probably doesnt exist, but you would have likely been very happy, and told everyone how well Tesla treated you, and "dont believe everything you hear about them".

Now? Exact opposite, and for what? Something Tesla could have remedied fairly simply just by giving you a less used battery.

/shrug...

In any case, it sucks, yeah for sure.

 

[MP3Mike]

Current full charge mileage indicated on this pack is ~205 miles which is about what I had previously

So it sounds like followed the terms of the warranty, and put you back to where you were before the failure.

 

[davewill]

I guess the BMS comes ”with” the battery so it should have a clue about the capacity.

For the warranty, the replscemrnt battery should hold at least the capacity ypur batt had ”before the failure”.

The timing for the capacity ”before the failure” can be a interresting discussion.

Perhaps not. Who knows how long that refurb battery sat, or what they replaced during the refurbishment process? It could be a brand-new BMS with no history at all.

Tesla goes out of their way to keep owners from knowing the true health and capacity of their batteries, probably to keep owners from complaining when their battery reads lower than others. It makes nearly tough to exactly what the health of the OP's battery was before that failure. Especially when third party tools results are routinely dismissed.

And as you point out, figuring out when the failure started and how much of the OP's degradation might have been caused by it it is another almost hopeless task.

 

[pipp]

Like, in this case, the "Right thing" doesnt have to be a brand new battery, but it really should be a "gently used" one with like no more than 6-7% degradation tops. If they gave you a new battery, or one with just 2-3% degradation, this thread probably doesnt exist, but you would have likely been very happy, and told everyone how well Tesla treated you, and "dont believe everything you hear about them".

Now? Exact opposite, and for what? Something Tesla could have remedied fairly simply just by giving you a less used battery.

My impression reading this site is that batteries don’t need to be replaced very often. So Tesla could, on the surface, easily afford to use new batteries to replace the bad ones, without taking a huge financial hit. But I wonder if Tesla worries about how many jokers are out there who would, if they knew the replacement batteries are new, they would then purposely degrade their batteries to the replacement threshold.

 

[Eric33432]

Perhaps not. Who knows how long that refurb battery sat, or what they replaced during the refurbishment process? It could be a brand-new BMS with no history at all.

Tesla goes out of their way to keep owners from knowing the true health and capacity of their batteries, probably to keep owners from complaining when their battery reads lower than others. It makes nearly tough to exactly what the health of the OP's battery was before that failure. Especially when third party tools results are routinely dismissed.

And as you point out, figuring out when the failure started and how much of the OP's degradation might have been caused by it it is another almost hopeless task.

If you register your Teslae with recurrent, you could have a monthly report on your car's battery health. Then, if you had a sudden decrease, you could point out that a month before it was, say 8%, not the 18% it was the day or two before it failed.

 

[jjrandorin]

If you register your Teslae with recurrent, you could have a monthly report on your car's battery health. Then, if you had a sudden decrease, you could point out that a month before it was, say 8%, not the 18% it was the day or two before it failed.

You could do that, but there is no guarantee (and Tesla is under zero obligation) to accept ANY third party battery report as anything more than "for educational purposes only".

 

[Eric33432]

You could do that, but there is no guarantee (and Tesla is under zero obligation) to accept ANY third party battery report as anything more than "for educational purposes only".

Still, it would be better than s**tting in your pants, as my friend from North Dakota likes to say, and is an otherwise interesting thing to see each month.

 

[AAKEE]

You could do that, but there is no guarantee (and Tesla is under zero obligation) to accept ANY third party battery report as anything more than "for educational purposes only".

Well, logging (and the logs from) the nominal full pack value direct from the BMS with Scan My Tesla would probably be accepted a it is only a third party app to find the value but the value is Teslas own from the BMS.

 

[3sr+buyer]

I plan on running the battery health check built into service mode. Running that on the old pack showed 81% health. Current full charge mileage indicated on this pack is ~205 miles which is about what I had previously

For warranty replacements, they promise to give a replacement battery at least as good as the failed battery was before failure. It looks like they fulfilled that promise.

 

[3sr+buyer]

I guess the BMS comes ”with” the battery so it should have a clue about the capacity.

However, if the used battery was previously removed from a car for warranty reasons, and the BMS electronics were the defective part, then the BMS may not have been on the battery for same amount of time as the cells.