2013 MS 60 Battery Failure, have 85 pack: How to swap?

[islandbayy]

So I would like to finally post an update on my pack swap for my old 2013 MS 60. So on March 20th, I dragged my S60 with replacement battery pack out to Mr. Erickson's place in Armstrong IA. The drive was successful and managed to get both battery and car there in one go.


The pack swap itself was very quick. Paul was able to do the physical swap in a few hours and did some firmware updates overnight. Paul Erickson was a pleasure to work with, an interesting guy and someone dedicated to Tesla Model S cars and helping owners keep them on the road.

The old pack came out OK, and was definitely getting a bit corroded. The usual suspects, the fuse cover plate was very rusted. Didn't look like it was getting water in the pack yet, but it wouldn't be long based on looking at it.

There were complications however. Once we got the pack swapped out and brought the car back on line it immediately threw some errors. One of the big concerns I had with this pack was that it was sitting in storage untouched for over 6 years. It was dry storage, but it wasn't charged or turned on or anything for that period of time. The other concern was I wasn't sure what state of charge it was left at when it was put into storage. It could have been near empty which would have been bad. Turns out I was lucky. It was at 65% state of charge when we turned it back on. However, during those 6 years of sitting idle, the battery did fall out of balance slightly. Almost all cell groups were perfectly balanced except group 42. That group was about 170mV lower than all the rest. I guess not bad since that 170mV of drift took 6 years to accumulate, but that did cause the car to immediately throw an error, and go into charge restriction. But I felt fairly confident that it was just due to sitting for 6 years and that the pack is overall healthy.

So, I left the car with him for a while to see what he could do. What we did was just simply cycle the pack as much as we could for a little while. Pretty quickly the imbalance was only about 120mV when the pack was down to ~25% state of charge. Did a few charge cycles and reset the error message. After that, it appeared that the error message did not come back. Due to work and other issues, I was not able to go pick up the car for about a month. I left it with Paul and he exercised the pack, did some test drives, supercharged the car a few times and no more error messages came back.

So this weekend I flew myself and my Dad over to Paul's place to pick up the car as it seems to be working normally. My dad drove it home and had no issues with the car driving back the whole way. It behaves just like an 85 pack should (nerfed supercharging) but seems to be good. Currently the cell imbalance is about 90mV @ 80% SOC and 120mV @100% SOC. A full charge yields about 230miles of rated range on the display. Paul is recommending that I try just slow charging to 100% everyday for a while to see if the pack starts balancing on it's own, so I will do that and give an update if that yields results.


Unfortunately, not all is well with the car. Unrelated to this battery business, just prior to me sending the car to Paul, the drive unit (I think) seems like it is giving off some vibration. But maybe more on that in another thread. As far as the battery swap goes, I consider it a success.

Thats Awesome!

Keep charging to 100%, it will keep balancing out. Lower SOC discharges to 100% help too. Since you have free supercharging, spend a couple hours at one getting to 100% (from any SOC). They balance better at a supercharger.

 

[islandbayy]

Well if only one brick out of 96 discharged so much more than it's probably a sign of either u029 or u018 coming...

The car already threw that error due to the brick imbalance. It shouldn't be much of an issue though, since as glhs said, it took 6 years to discharge that much. much. It only threw the error because the imbalance was there when they powered everything back up. With the error reset, and the car (slowly) balancing out the pack again, it should be good for quite a while.

That amount of discharge after being shelved 6 years is actually REALLY GOOD. cold storage, especially at that SOC, in general, likely would have been fine on that shelf for a number more years
Heck, I store batteries around 50-75%, and even my first laptop, which I got October 21, 1998, still holds about 75% of it's original charge, on it's original lithium battery Proper storage is key, looks like this battery was stored properly.

 

[brainhouston]

...That amount of discharge after being shelved 6 years is actually REALLY GOOD. ...

Sure i agree
But 95 bricks that didn't lose that extra 170mv is even Better
They all sat for 6 years..
My point was that since one brick is weaker it'll continue to degrade faster...

 

[islandbayy]

Sure i agree
But 95 bricks that didn't lose that extra 170mv is even Better
They all sat for 6 years..
My point was that since one brick is weaker it'll continue to degrade faster...

Oh of course, I'm not denying that. But given the circumstances in which it took to discharge that much, in the grand scheme of things, and if the vehicle is going to be used regularly, it's a drop in the bucket Should give plenty of life on his 2013.

 

[Recell]

this pack has been sitting a VERY long time, so needn't be a weak short u029 bleed out. However barring some rapid turnaround and some serious, serious balance charging - possibly weeks or months worth - we suspect it's in, or soon will, be in the u018 territory.

@glhs272, we definitely want to see this work for you! keep us posted on your progress!

 

[glhs272]

Unfortunately, not all is well with the car. Unrelated to this battery business, just prior to me sending the car to Paul, the drive unit (I think) seems like it is giving off some vibration.

Good news, the vibration was just a simple tire problem. Drive unit is still smooth as glass at over 200K miles.

 

[glhs272]

this pack has been sitting a VERY long time, so needn't be a weak short u029 bleed out. However barring some rapid turnaround and some serious, serious balance charging - possibly weeks or months worth - we suspect it's in, or soon will, be in the u018 territory.

@glhs272, we definitely want to see this work for you! keep us posted on your progress!

Recell,

You are correct. Unfortunately, the BMS u029 error has returned. I have been monitoring pack balance every day since I got the car back. I have been logging the pack balance when the battery finishes charging (98%SOC). Although the pack balance has not gotten worse, it has not gotten better. It was usually 114mv to 119mv out of balance at 98%SOC. Typically, the low cell would always charge to around 4.054mV. Any variation in cell balance at that state of charge was usually due to the highest voltage cell being slightly higher or lower when charge completed.

So where do I go from here....?

Plan A: Repair
Looks like if I want to continue to try to use this pack, surgery on the pack will be required. Unfortunately, there is so much incorrect/misinformation regarding these pack repairs. Folks post their successes in repairing packs, but it's hard to know if it is BS. Or the pack returns to error state after a few months in operation. What I want is a repair that will be long lasting (preferably 10+ years or 250K miles). I am dreaming, I know... Also, pack repairs look expensive due to the amount of labor going into doing it. Doesn't seem like it makes sense to put many thousands of dollars into repairing a pack that will just fail again in a few months or a year. But for a though exercise what would pack repair options be?
-1)Remove the out of balance module, manually re-balance the module back in line with the rest, then reset the error and cross fingers. Seems like a low chance at success with this one. Only considering it given the known history with this pack and the length of time it took to get this far out of balance.
-2)Remove the out of balance module, try to find the bad cell(s), remove them, and re-installing a replacement cell. Rebalance and try running it again. This method takes some good diagnostic abilities to correctly identify the bad cells. Takes even more trickery to actually swap out a bad cell without starting a fire or ruining the module in the process. This method is also impractical if there are several or more bad cells. Also not sure of the longevity of the repair.
-3)Remove the out of balance module, and replace with a known good module. Intuitively, this would seem like the best repair. However, based on everything I have read to date, this is not as easy as it sounds. Basically, as I understand it, I would have to find a near exact match of a module for my existing modules. Such that the replacement module has exact capacity, resistance, charging and discharging characteristics, etc. Maybe possible, but many have tried and failed.
-4) Other? I am not aware of any other known techniques.

In either case, it may be a good idea to move the bad or replacement module to position 9 (under the battery hump) to make it easier to fix, repair, or swap the "non-original" module in such a case were periodic maintenance may be required.

Plan B: Replace
-1)Forget this pack. Roll the dice again, and try to buy/obtain another complete pack. Hopefully, one that is healthy. From what I am seeing this is still going to be very expensive. Typical ebay prices of older 85 type packs are still going for 5-8K. A lot to spend on a pack that is notorious for faulting in the not to distant future. Also, very hard to know what you are starting with. A pack already out of a car is hard to determine it's health. 100Kwh packs are going for 12K. Not even sure its possible to put one of those in my old S.

-2)Buy a complete, but perhaps wrecked car. If the car is intact enough to power it up to read the CAN bus and determine the relative health of the pack, I might have better chance of success in getting a good pack. I have been looking around on copart and there are many wrecked model S cars to choose from. But still going to be expensive. Does get me more parts to work with, such as drive unit, to keep the car going in the long term. So something to consider, but out of my target price range.

Plan C: Reconfigure pack
-Go to the Recell method. Have pack converted to a 14 module pack with the remaining good modules. If I were to pursue this method, I would prefer to do it to my 85 pack, rather that giving my pack as core exchange and getting back an even more unknown pack. This is still probably an expensive repair.

Plan D: Give up.
-I am still willing to put some more money into this old car. But I have limits. If I had a sure fire repair for $5K, I would do it. But this old 2013 Model S with 250Kmiles is not worth much. Mostly just sentimental value to me. Although the car is in relatively good condition, there are other things on this car that are worn and will eventually need attention regardless of the battery issue. I can only stomach putting in so much money. And considering what a low mileage used Model 3 goes for these days, maybe worth just moving on from Tesla Model S life...

Any suggestions welcome.

Thanks