3.0 Battery Longevity

[shrink]

They better give you a P100D as a loaner, but damn that sucks.

Tempe Service Center, where I assume @thebabydoc also gets service, gave me a brand new P100D loaner yesterday.

It had Chill mode enabled and I was unable to disable it.

It was like she was wearing a chastity belt...

Congrats on that purchase @thebabydoc! Very impressive and a smoking deal. If you ever want to buy my Roadster for an easy local transaction let me know. I'll probably be listing for sale soon, but mine pales in comparison to the one you just bought. Wow.

 

[thebabydoc]

Tempe Service Center, where I assume @thebabydoc also gets service, gave me a brand new P100D loaner yesterday.

It had Chill mode enabled and I was unable to disable it.

It was like she was wearing a chastity belt...

Congrats on that purchase @thebabydoc! Very impressive and a smoking deal. If you ever want to buy my Roadster for an easy local transaction let me know. I'll probably be listing for sale soon, but mine pales in comparison to the one you just bought. Wow.

Thanks, but I would not want to insult you on the offer, I only buy where there is room to sell .

I go to the Scottsdale center, maybe I should go to Tempe.
The problem we're going to have is that they want to store it outside. FOR UP TO 6 MONTHS?!?!

This time was serious BS as I was the first one there that morning and I got a 48K mile 2013 S 60.
Still drives better than 99% of the cars out there!
The last S100 they gave me did not have the speed limiter, though LOL.

 

[shrink]

I go to the Scottsdale center, maybe I should go to Tempe.
The problem we're going to have is that they want to store it outside. FOR UP TO 6 MONTHS?!?!.

I think Scottsdale has storage space at the nearby Scottsdale airport? So it might be stored in a hangar? I could be wrong about that.

Tempe doesn't have a lot of parking. Their lot is usually quite crowded and is currently filled with a bunch of Model 3's to be prepped for delivery. Not sure where they would store your car during the lengthy repair, but it can't hurt to ask.

 

[gregd]

/begin rant/
Regarding "storage"... My first reaction would be to tell them to gather all the parts, instructions, expertise, and technicians, and let me know when they are ready to do the work. I'd keep the car at home, plugged in, until then. If the battery is failing, pull the disconnect to keep it in stasis, if necessary. Having them "work on" the car for months, it becomes more like a spare-time hobby for them, and that's not what I'd be paying them for. Actually swapping a battery pack is a matter of a few days' work, at most.

It really annoyed me (I used a different word at the time) when I made an appointment for service a few months ago, and was told when I arrived (on time) that there were several cars ahead of me and it would be a day or two before they could get to mine. My expectation was that the appointment was for actual service, not an appointment for getting into the queue for service. I understand that sometimes things happen and they get behind. If so, I should have been called to reschedule. Giving me a Model S, which does not fit in my garage, so it was in the way on the driveway, and leaving my car out in the 100 degree sun for most of 2 days (I have an OVMS installed and was watching in dread as the battery temp kept climbing, and SoC kept dropping) does not come close to "service" in my book. And all this to fix an issue they had caused a few months earlier, over-filling the HVAC system during the annual service.

I really hope they get their act together, and treat service the way it should (used to) be done. My next service appointment will be made with a very clear up-front discussion of expectations.
/end rant/

 

[ecarfan]

Moderator note: Please stay on topic for this thread, which is longevity issues with the 3.0 battery. Thank you.

 

[thebabydoc]

So here's a hypothesis. The CAC algorithm doesn't get any data unless you range charge the car or run it to very low SOC. Otherwise, it's a complete guess based on what the engineers thought when they wrote the code. When you DO range charge or run to low SOC, it gets some data, but it averages that in with what it already thinks (which may be based on old data, or may be based on lots of guessing).

The guesses that it makes are essentially just drawing a line from when it was new to the current time. However, when it gets new data from a range charge, it not only adjusts the CAC, it adjusts its estimate of the slope of the line. So, range charging not only increases the CAC, it decreases its rate of decline. Again, this isn't saying that it helps the cells (it almost certainly doesn't), it's that it helps the estimate.

As evidence of this, I made the following chart. It's really simple. I just pulled the CAC-vs-miles chart for my car (#670). Then, I chose four range charges that I did (usually really several in a row) that made the CAC go up. Then, I drew straight lines from the starting CAC and 0 miles through the peaks. The fact that the CAC more-or-less follows the lines until I start range charging again fits the hypothesis reasonably well.

So then that lets us ask what the real degradation curve looks like. For that, I just drew a smoothed line through the same peaks. This gives the second graph. And *that* graph shows a strong suggestion of the degradation rate slowing down. Of cells that lose some capacity and then stop getting worse for a while. This, of course, is only one car with four data points. Furthermore, I range charge much more often than I run the battery down to low SOC, so the algorithm is only seeing the top of the battery, and we're not all that sure what's happening with the bottom. Still, less discouraging than news usually is in this thread.

This should also make it obvious why I really want someone else who's got a car with low CAC and range charge it for a number of days in a row, until the CAC stops climbing. If it winds up somewhere near my smoothed curve, then maybe we're on to something. You don't have to drive the car too much, just let it range charge a number of times in a row. It didn't kill my battery, it probably won't kill yours.

View attachment 308927 View attachment 308928

I'll do it but you need to respond to my e-mails or posts- I sent you the logs for 1434 and have not heard back from you.

 

[thebabydoc]

Here's the latest update, with new data for 707, 330(EU) and 670. Thanks thebabydoc and dpeilow.

707 stands out as the quickest CAC drop by mile of any car, but it's in the middle of the pack in the by-day graph, so I think all we've learned is that calendar time is more important and it's a very low mileage car (1500 miles in a year, roughly).

330(EU) is doing better than most cars both by-day and by-mile, but if you were to just eliminate the section where it was reset at about 2.5 months/1K miles it would be pretty typical. This may be among the most interesting pieces of data in the whole data set. If what we were seeing was based on what was happening in the cells, then you'd expect the effect of the reset to go away, since it was all software and no hardware. The fact that it's just a constant offset makes it look like most of the signal isn't all that related to what's happening in the cells.

And, yes, it's taking some pretty big drops recently, but it also mostly wasn't driven over the winter, so it's just catching up to the baseline, I think. Though I do like the idea that hard driving has a disproportionate effect. I'm not sure how I could measure that from the data that I have. While I do have some of the short-term logs were I could figure out speed and acceleration, they're pretty limited. Maybe I could work with what I've got, I'll have to think about it some, it's an interesting idea.

I also added about 6 weeks' data for 670. It's continuing to be remarkably level. It first hit its current CAC back in November, 8300 miles ago. Maybe it really has hit a knee in the curve, but I'm still somewhat skeptical.

View attachment 308601 View attachment 308602 View attachment 308599

Do you think it's just a coincidence that the battery failed on 0707 at the 1-year mark or could this have been a warning sign?

 

[suburbancurse]

Much appreciate this thread... I've learned a ton from it.

We own Roadster 1338 (less than 3000 miles) and I'm currently having an issue pulling OVMS logs... but will figure it out once I have vehicle back in my possession (currently at local SC)
Our factory battery completely died some time between June 29 and July 3. We have the $12k battery replacement warranty and I can confirm my options from Tesla are a)receive an original remanufactured battery at no cost or b) 3.0 upgrade for $6k. I've also been informed that the warranty only entitles me to one of those benefits... i.e. I cannot go for a remanufactured original and decide at a later date to go for a reduced price 3.0.

I have inquired to SC about 3.0 degradation issues and received a canned "We haven't seen it... and we've worked on N Roadsters" response.

Wondering if any folks on the thread have been a similar situation - had the need for a new battery but wavered between old and upgrade.

FWIW - our low mileage was due to hectic travel/family schedules and as we see that ease, we anticipate putting 3000-5000 miles on the vehicle annually, however we're likely not to do more than 150 miles round trip.

 

[backmost]

Is getting an original remanufactured battery even an option? I feel like a few Roadster owners have been told they have to go with the 3.0 battery if they had any issues

 

[Rolf68]

We have the $12k battery replacement warranty and I can confirm my options from Tesla are a)receive an original remanufactured battery at no cost or b) 3.0 upgrade for $6k.

Personaly I would go for the upgrade. $6k is a good price and that would increase the car's value by far more in my opinion.

I wish I had the same warranty

 

[backmost]

Definitely agree with going for the 3.0. Newer chemistry, longer range, and future proofs the car in case you want to sell down the road (pun intended)

 

[suburbancurse]

Is getting an original remanufactured battery even an option?

Yes, and according to SC the remanufactured battery takes less time (~4-6 months) than 3.0 (~6-8 months).

 

[Kerios]

Rumours of 3.0 taking at least 12 months now, I went for the 3.0 over the 2.0 replacement as part of my battery replacement agreement, it cost £5k ($6k) and to be honest has made the car significantly (for now) more usable. The three year warrenty also is a nice perk for resale purposes if desired.

 

[ICON]

I was told 12-18 months wait here in Hong Kong and went ahead and ordered the R80 3.0 on April 21at 2018 but no news on delivery, they seem clueless at the SC.

 

[bolosky]

Here's an update with more data for my car (670) and thebabydoc's new car (1434). I'm sorry, thebabydoc, that it's taken me so long to get back to you. I've been out of it for a while.

1434 look pretty typical of moderate mileage cars, sitting in the middle of the pack for both by-miles and by-days. It's lost 13 Ah in about 6K miles and a little more than a year, which is slightly better than average, but not too far off.

Much more interesting is what's going on with my car. The CAC seems to have leveled off at about 190, and hasn't really declined any in 10K+ miles and about 9 months. This kind of thing is consistent with some of the discharge-vs-capacity graphs I've seen for some cells where they have a steep initial dropoff followed by a very long level plateau, and then an eventual steep decline into death. If that's in fact what's happening, then it may be that we don't have problem so much as a battery that's effectively 12% smaller than advertised and that will sit at that level for many years/100Ks of miles. I can live with that if that's the case.

To be more confident in that, though, I'd like to see two more things. First is other cars behaving like mine is. None have so far, which may be for one of a number of reasons. The most obvious is that I have the highest mileage in the study by more than a factor of two, so other cars may not have gotten there yet (though two of them have lower CACs than mine). Second is that I think I range charge more often than others, and I have a strong suspicion that range charging gives the CAC algorithm data that it needs to calibrate, and that without doing that the algorithm may err on the low side (which doesn't mean your cells are worse, just your car's estimate of them). And finally my car may be an outlier on the good side for some reason.

The second thing I'd like to see is evidence that the CAC algorithm isn't messing up the bottom of the battery estimate. Getting this involves running the battery to very low SOC, which rarely happens for me or anyone else. I'm considering doing an experiment about this, though. What I'd do it range charge the car, then drive it until it's at very low SOC, then park it unplugged and run the heat/AC until the SOC gets to a few percent (followed by immediately charging it). I'd look to see how many amp hours the car thinks came from the battery (and how much it thinks remains) and compare that to the CAC. That will give a much better idea of whether there's an error in the CAC (in either direction) and will also give the CAC algorithm some more data, so we can see how it updates.

I'd love to hear comments on the plan before I do it. I'd hate to really damage my battery by running it too low, but I think the car would make it hard to do that unless I let it sit too long. Any thoughts about what I else I can do/measure?

Without further ado, the graphs.

 

[hcsharp]

I'd love to hear comments on the plan before I do it. I'd hate to really damage my battery by running it too low, but I think the car would make it hard to do that unless I let it sit too long.

The cells in the 3.0 battery are capable of discharging lower than the Roadster's charging system is capable of going. As a result they are never discharged completely even when you hit 0 miles in range mode. Does this mean you'll do less damage to the cells with a deep discharge than the OEM cells? Probably. But I doubt if anyone knows for sure. Personally I wouldn't hesitate if it was my own car, but I don't have the 3.0 upgrade.

 

[dpeilow]

If you look at the charge cycle graph for what was supposed to be the original Roadster cell, you can see a slight curve at the beginning of life but it then degrades linearly. It is at 250 cycles before it has lost 12%. We are not at that level (of range mode charges) yet with the new cell, so this is clearly a much more pronounced degradation.

Datasheet

 

[ion_1]

If you look at the charge cycle graph for what was supposed to be the original Roadster cell, you can see a slight curve at the beginning of life but it then degrades linearly. It is at 250 cycles before it has lost 12%. We are not at that level (of range mode charges) yet with the new cell, so this is clearly a much more pronounced degradation.

View attachment 329711

Datasheet

Agreed re the original LCO cells. These were very robust cells.

However, certain cell chemistries such as those with a good bit of Si in them can give a large upfront cell loss approaching but not exceeding 20%. then the cells cycle well. For example the 3.0 rumored LG "HG2" cell has a very sharp 15% or more loss within the first 100 cycles then cycle well. (BTW, I have not seen evidence that these are the cells in 3.0). I still hold back a bit on my full criticism of these cells until I see cells cross 20% loss without a significant plateau develop. Bolosky's data seems to show that there may be hope for these cells. If these cross 20% then I have a very severe problem with the 3.0. What is surprising is that the aforementioned fade data is based on full depth of discharge cycling. Something few/none of those above are doing.

That being said, I would be extremely surprised if Tesla did not expect this behavior from these cells. A high initial capacity so claims on great range can be made. Then a subsequent loss, but level above the 20% mark which is a traditional mark of excessive degradation in batt world to stay out of trouble. This is misleading for those who really care about range, and if I bought the 3.0 specifically for range, I would be annoyed (especially for $30k). Personally, i just want (and will soon need) a replacement battery with no drama that lasts 50% longer lifetime than my original pack. This batt may still do this, but I can't wait and watch Bolosky post data for another 10 years before I purchase..

Valuable data as usual, thanks Bolosky.

 

[dpeilow]

If true then I think it raises two important points:

1) The EV world needs to come up with a better metric than just quoting the range on the first cycle. Coming from the satellite world we design for End Of Life performance of cells and PV cells, not the marketing numbers at the Beginning Of Life. If EV manufacturers carry on like this it will come back to bite them. Of course, knowing a little about cells and chemistries I expected a kink in the cycle curve but not something this pronounced.

2) Tesla could end the speculation with a statement and data to back it up. They must have done accelerated testing before putting it in our cars, right? I have heard from my service centre that the 3.0 program is on hold while they are looking into this, that they suspect it is a chemistry issue and they are considering sheet swap-outs. That was verbal from the manager there, so I have nothing else to back that up, but it does tally with the very long wait times people are being quoted for new 3.0 orders.

 

[hcsharp]

I have heard from my service centre that the 3.0 program is on hold while they are looking into this, that they suspect it is a chemistry issue and they are considering sheet swap-outs. That was verbal from the manager there, so I have nothing else to back that up, but it does tally with the very long wait times people are being quoted for new 3.0 orders.

We all know about the lack of reliability of service center sourced information. The fact that it came from a manager gives me a ray of hope. If it's true then it's really good news.