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Service says $22k for new battery on 2012 Model S

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
5,721
12,198
Hickory, NC, USA
So Hoovies story got a sequel via the Rich Rebuilds channel. Apparently the Electrified garage changed the bricks that were of balance with closely matched bricks.
@wk057
you mentioned that this is not the preferred way of working/best solution. I am curious what the ownership experience of Hoovie will be with this repair done to the tesla.


I didn't catch this earlier... yikes. This just shows how little people know about these devices, especially high profile folks like that with more marketing budget than knowhow.

Yeah, that car will be dead on the side of the road eventually as a direct result of that "repair". Pretty much guaranteed. The only way it wouldn't happen is if the car isn't used much at all (like, a charge cycle per month or so)... then it'd probably be fine. But under normal use? Nope. This type of "fix" always results in the BMS being like, "Nope!" as a result of the perpetual and uncorrectable imbalance.

Sure, it'll function when put back together if things were manually balanced initially. But give it a few cycles. Maybe a few dozen if they're "closely matched" as claimed. Or go supercharge it from empty a couple times immediately after a full drive.

Like I said, it may not complain immediately, and the exact conditions will vary depending on actual usage... but inevitably the BMS will give up and throw codes and disable the HV battery.
 

MP3Mike

Well-Known Member
Feb 1, 2016
16,422
38,302
Oregon
This type of "fix" always results in the BMS being like, "Nope!" as a result of the perpetual and uncorrectable imbalance.
How far out of balance does it need to be to trigger the shutdown? (We have seen a few people with a ~90mV, up to a 320mV, imbalance on new Plaid Model S vehicles where the SoC is wonky, charging stopping at ~90% and then jumping to ~100% overnight while not being charged, and rated miles being way lower than it should be. And they have yet to through any non-hidden warnings/errors. Thread here: "Balance Required" BMS Alert on Plaid)
 

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
5,721
12,198
Hickory, NC, USA
How far out of balance does it need to be to trigger the shutdown? (We have seen a few people with a ~90mV, up to a 320mV, imbalance on new Plaid Model S vehicles where the SoC is wonky, charging stopping at ~90% and then jumping to ~100% overnight while not being charged, and rated miles being way lower than it should be. And they have yet to through any non-hidden warnings/errors. Thread here: "Balance Required" BMS Alert on Plaid)

That wouldn't fly on a non-Plaid for sure. I haven't fully dissected the Plaid BMS, so there must be some change there. There's also 110 cell groups vs 96, so even more balancing errors possible (it's exponentially more difficult the more groups their are).

Keep in mind it's not necessarily directly about the voltage delta that causes errors. While a gross delta certainly will cause a problem, the BMS generally will just do its best to keep things in line as long as the imbalance is under 50mV or so. (Other factors here... for example, a 20mV imbalance in the 3.5-3.8V range is WAY worse than a 50mV imbalance at the 4.1-4.2V range, for example.) However, the BMS does way more than this. It tracks the usable capacity of each group, and the actual you-cant-drive-anymore errors happen when these calculations have a significant delta with the pack as a whole... as is guaranteed to be the case if a full module or two are replaced with random eBay modules. These calculations take time, however, so if the gross imbalance fault doesn't kick in, the one that will is the SoC imbalance fault. This is uncorrectable by nature. While the BMS can fight against voltage balances all day long, it can't fight hard enough to correct for an SoC imbalance that's more than about 0.5%.

There's a few scenarios. The most likely are that either the replacement modules have more capacity than the rest of the pack, or they have less capacity.

The 150 yard view of this is basically this:

If the replacement has more capacity, then the rest of the pack will reach CV cut voltage before those modules, and the max pack voltage will be limited below the normal max to correct for this. Because the higher capacity modules can't reach peak voltage, on the lower end they'll hit a lower voltage before the rest of the pack and thus you end up with an SoC cap on both ends of the full range. Eventually this imbalance grows to the point where the BMS's algo catches up and decides it's unsafe. A best case scenario is it never shuts down, but you have a car that charges to 50 miles at 100%.

If it has less capacity, the replacement reaches CV charge voltage earlier than the rest of the pack and the remaining modules are stuck at a lower voltage despite the BMS being at "100%" well inside the real max SoC window. On discharge, the replacement modules, depending on how out of whack they are with the pack, can either end up at a higher local SoC than the rest of the pack during discharge (since they reached CV first), or be far enough away that they stay in this cycle near the bottom, leaving the full SoC window shrink on the top end.

Either way, the replacement modules are being cycled at different voltage ranges. This exaggerates the issue over multiple cycles, and eventually the BMS's calculations trip the tipping point and you're done.

There's WAY more detail to go into here about why this never works, and is actually unsafe to do in general. Tesla's BMS is quite robust, however, so the safety risk aspect of such a "repair" is pretty minimal... but it will invariably result in an unusable vehicle eventually with very very few exceptions.

Long story short, there's just no way two random modules procured from wherever will match closely enough to be drop in capable in a pack for replacement and work indefinitely. I'd estimate the odds of success being somewhere in the 1 in 200,000 area for a single module replacement being successful based on all of the data I have at my disposal (directly captured BMS data from hundreds of vehicles, plus indirect data from elsewhere). Maybe 1 in 1000 chance that normal use doesn't trigger a problem within a year.
 

krishna3812

Member
Jan 7, 2021
42
40
Newyork
Saw this on Twitter.
Screenshot_20210913-234701.jpg


Seems like reman came down to ~11k?
 

ucmndd

Well-Known Member
Mar 10, 2016
6,987
13,775
California
The price does seem to be coming down over time, for both new and reman, and there does seem to be inconsistency in pricing from one customer to another.

Something is fishy with the whole Hoovie story. The $22k estimate they flash on the screen in the video has a date from 2019.
 
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RandyS

Fan of Elon
Jul 8, 2012
731
959
San Diego
@wk057 I respect all of your work and knowledge with Teslas and batteries. I own a 2013 P85 that I bought new and still enjoy driving it, although it is out of warranty (and I am getting nervous when reading threads like this) :) . One thing I am confused about with respect to your statement above about the difficulty of swapping out modules to refurb a pack...I know that you've said that you have really tried to match up modules (same age, etc.) to refurb packs and have had issues.

Obviously Tesla is providing refurb packs for both in and out of warranty battery repairs and they take the "bad" packs back as part of the "core charge" process, so there has to be a way for them to refurb a pack that makes it usable and reliable again?. What do you think they are doing to refurb packs that make them usable and reliable again? It seems like there has to be something...It would be very bad PR if the truth was that they have to recycle or discard packs because one module has a problem...Thanks....
 

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
5,721
12,198
Hickory, NC, USA
@wk057 I respect all of your work and knowledge with Teslas and batteries. I own a 2013 P85 that I bought new and still enjoy driving it, although it is out of warranty (and I am getting nervous when reading threads like this) :) . One thing I am confused about with respect to your statement above about the difficulty of swapping out modules to refurb a pack...I know that you've said that you have really tried to match up modules (same age, etc.) to refurb packs and have had issues.

Obviously Tesla is providing refurb packs for both in and out of warranty battery repairs and they take the "bad" packs back as part of the "core charge" process, so there has to be a way for them to refurb a pack that makes it usable and reliable again?. What do you think they are doing to refurb packs that make them usable and reliable again? It seems like there has to be something...It would be very bad PR if the truth was that they have to recycle or discard packs because one module has a problem...Thanks....
The bulk of issues in older packs are problems with electronics, cell sense leads, etc. Not actual cell issues. So Tesla can in fact refurbish a good percentage of the older packs, update their sense wire setup, etc.

They don't replace modules. I've personally opened 20+ refurb packs and the modules were always all original to the pack.
 

ucmndd

Well-Known Member
Mar 10, 2016
6,987
13,775
California
I think that's a reasonable stance, if there's reason to believe the repair is lasting and durable. Having an option like this to replace, say, a failed battery management board is a game changer.

But if you're charging someone $5-7k for a "repair" that has a high likelihood of failing again in the very near term, have you really helped them?
 

No2DinosaurFuel

Active Member
Apr 16, 2015
1,407
859
San Diego, California
I think that's a reasonable stance, if there's reason to believe the repair is lasting and durable. Having an option like this to replace, say, a failed battery management board is a game changer.

But if you're charging someone $5-7k for a "repair" that has a high likelihood of failing again in the very near term, have you really helped them?
Not suggesting this, but the repair might make your car resale value worth something to the uninformed. So they owner can pawn it off to another idiot we didn't do their homework. Personally, I think the only fix is to make battery replacement so cheap, that people don't think about it. Make the whole NEW pack cost $5K to replace and I'm sold Tesla has a solution to this problem. However given the wholesale price of 1KWh pack is still somewhere in $145 range, I seriously doubt we are anywhere near at $5K per pack given all the other stuff involved in building the pack in addition to the batteries itself.
 
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OlderThanDirt

Member
Apr 19, 2015
248
249
Two Rivers, WI
I would interested in @wk057's thoughts regarding GM's announced plans to replace potentially bad battery modules (if they can figure out how to determine which are bad). The Bolt owners I know are more than a little apprehensive about that plan for numerous reasons. They just want a completely new pack.

I do want say how much I appreciate you sharing your knowledge on this forum.
Thank you!!!!
 

SO16

Active Member
Feb 25, 2016
3,208
10,379
MI
I think that's a reasonable stance, if there's reason to believe the repair is lasting and durable. Having an option like this to replace, say, a failed battery management board is a game changer.

But if you're charging someone $5-7k for a "repair" that has a high likelihood of failing again in the very near term, have you really helped them?
I should have stated there are several tweets in that string. Worth reading for more detail on his viewpoint.
 
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tga

Supporting Member
Supporting Member
Apr 8, 2014
4,022
2,986
New Hampshire
The bulk of issues in older packs are problems with electronics, cell sense leads, etc. Not actual cell issues. So Tesla can in fact refurbish a good percentage of the older packs, update their sense wire setup, etc.

They don't replace modules. I've personally opened 20+ refurb packs and the modules were always all original to the pack.
I believe this is what caused my pack failure last Sept. I had several errors (BMS_f098_HW_BMB_Over, BMS_f017_SW_Brick, BMS_u018_Max_Charge, possibly others). I had charged the car to 70% and it was sitting plugged in when the problems started. SoC shown on the app was bouncing around a wide range, mainly 30%-100%, but occasionally showing 0%. By the time the tow truck showed up, the car had completely died and I needed to jump it.

I was monitoring cell voltages with Scan My Tesla, and one pair of adjacent cells groups in module 7 were giving whacky readings. Overall avg 3.697V, with a range of 3.692 to 3.6704 on the good ones. The whacky pair's readings were bouncing around wildly, with one low (often <3.1V) and one high (often >4.3V), but the average was always around 3.7 (one screenshot I have shows 3.397 and 4.012). I think a failed voltage sensor, lead, etc caused readings that caused the BMS to have a hissy fit.

II got a refurb 1088815-01-E under warranty. Interestingly enough, it shows the exact same range at full charge as the original, 251 miles. I have not yet hooked up SMT to look at the new pack stats. Whoever got mine got a good one - well taken care of, ~5% degradation after 6 years, rarely charged over 80% except before trips. About 1/3 DCFC, 2/3 AC.
 

krishna3812

Member
Jan 7, 2021
42
40
Newyork
To add to this, I see people thinking this might be 75kwh battery pack but I don't think so.

When my model s 85 have battery issue this is what the sc ordered for my car. However they later returned my car with reman 90kwh pack.

Additional parts have been ordered for servicing your car. We will send you updates twice a week until your service is completed.

Parts Outstanding
  1. ASSY,HV BATTERY,85Kwh,1.0 Pack,REMANUFACTURED,MDLS
    Part #: 1088815-01-D
    Order Date: November 20, 2020
    Ship Date: Pending

So I think above ~$11k quote is for reman 85kwh
 
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tga

Supporting Member
Supporting Member
Apr 8, 2014
4,022
2,986
New Hampshire
To add to this, I see people thinking this might be 75kwh battery pack but I don't think so.
1088815-01-x is absolutely, positively, a remanufactured 85kWh pack. Anyone who claims otherwise is just plain wrong. That's what was installed in my car when the original pack failed (see above).
IMG_20200903_115102.jpg
 

GenSao

Member
Aug 3, 2017
565
966
Pleasant Hill, CA
The price does seem to be coming down over time, for both new and reman, and there does seem to be inconsistency in pricing from one customer to another.

Something is fishy with the whole Hoovie story. The $22k estimate they flash on the screen in the video has a date from 2019.

Indeed. The image was doctored from a Supercharger Receipt. See below...

 

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