3.0 Battery Longevity

[Peter.h]

Adding another one - when I bought my roadster the 3.0 battery was high on the list (I actually had baked it into my budget), but after following this thread for the last couple of month I have not pulled the trigger. My original battery still is within 15% of spec after 7 years with no sign of degradation of the 4,000 miles since I bought it

 

[bolosky]

Updating with four months' new data for #209. She's put on 800 miles and lost 3 Ah of CAC, which is pretty much par for the course.

Thanks, msjulie!

 

[dpeilow]

Number 2 seems to be the outlyer here, but it looks like it hasn't been driven enough to recalculate.

 

[dpeilow]

OK here's the letter. Forgive me the lengthy introduction, but I suspect the majority of the current staff have little knowledge about life before Model S, so need to set the scene. For those that have said they will sign, many thanks. If others also want to join, please let me know by tomorrow evening (UK time, so about 20 ish hours from now). If you like, please PM me your full name so that I can add it to the letter which I will send by email.


Dear XXX,

Many thanks for speaking to me about the Roadster 3.0 battery and PEM issues at the Clubhouse event on Thursday night and for giving us the opportunity to have a further dialogue on these topics. As requested, I am putting the issues that the Roadster community has seen into writing, in the hope that you may pass this to Tesla corporate to bring the issues to their attention.


Summary of the Issues

In a nutshell, there appears to be an issue with Roadsters that have been upgraded to 3.0 (R80) specification, whereby the battery capacity is degrading at a much faster rate than the original battery packs. It is not clear if this is a real effect from the battery or just a problem with the way the car is calculating available capacity and reporting ideal miles. The owner community is clearly keen to know.

Additionally, many owners of both 3.0 and older specification cars are starting to see minor faults turn into expensive repairs that perhaps could be avoided if Tesla was more flexible in allowing service centres to repair cars at the component level or making necessary information available to third parties.

I explain both topics in more detail below. Graphs of the battery degradation are attached to this letter.


Background

As we are sure you can appreciate, the Roadster community are some of the earliest and most enthusiastic supporters of the company and its mission. Many of us have been alongside the company from day one, either as owners or spreading the word about EVs and Tesla through social media.

Personally speaking, working in the space industry, I was a keen follower of SpaceX from the start and had already met briefly with Elon Musk prior to the public launch of Tesla in 2006. Having also followed developments in EV technology for years, the announcement of an electric sports car piqued my interest and I became one of three moderators on Tesla Motors Club when it was the only online resource for owners and enthusiasts worldwide. Following this, I was invited to the European press launch of the Roadster in 2008, and thus one of the first members of the British public to drive the car; I was at the opening party of the original London Tesla store in Knightsbridge in 2009; I drove the first ever one-day London to Edinburgh trip by EV (in the Roadster which I now own) in 2011; co-piloted the first EV trip from John O’Groats to Land’s End, again in another Roadster; joined the convoy of Roadsters that went to the Model S launch in Geneva in 2012; installed the first public Tesla HPWC in the UK back in 2010 (which was the forerunner of today’s destination charging) and had a substantial hand in installing the rest of the UK Roadster HPWC network (which set the template for the supercharger network and which staff at the time said was instrumental in selling more cars). Additionally, I have advised the SMMT and OLEV on charging networks and standards, going back to the same era. I suspect there were few, if any attendees at the Clubhouse event with connections to the company going back as far as mine.

In addition to my Roadster, which I bought as soon as I had the means and when the right car came up for sale, I am also a Model 3 reservation holder and it is fair to say that I would be a Model S owner if the garages at my block of flats were big enough to accommodate the car. I am also friends and in regular contact with Roadster owners worldwide: It seems many like-minded people bought the Roadster, we generally get on well and I always try to call in to see them when in the neighbourhood or vice-versa (only this Christmas I was enjoying a day in the workshop with follow owners in Stuttgart, servicing and upgrading a couple of Roadsters while the rest of the family went shopping). I am also still friends with and in regular touch with many of the former technical staff and senior management from the early years of the company.

I know that the other signatories of this letter have similar stories. We have first generation owners, some of whom put down the full price for the car on launch day in 2006 and stuck with the company during the difficulties and delays bringing the car to market, and we have second generation owners who have been Tesla supporters for a long time and who bought a Roadster as soon as they had the ability. Many have other Tesla cars and products at home or on order, in addition to their Roadster. All of us know the importance of the company and its mission and want it to succeed, and witness on a regular basis how the Roadster is still a halo car for the company.

Any feedback on problems like these is not meant in a negative light, but meant to be a heads-up on issues that are definitely affecting us now and could well have implications for the more mainstream models going forward too. We also wish to stress that this is in no way a criticism of any individuals anywhere within the company, all of whom go above and beyond wherever possible to help and who we know are typically deeply knowledgeable about the cars and the wider issues of EV ownership, but nevertheless I know are also under tremendous pressure to deliver as the company grows into a mainstream manufacturer and is joined in the market by the established players.


Roadster 3.0 Battery

My reasoning for getting the 3.0 battery for the Roadster was mainly down to preserving the car for as long as is realistically possible. It is very rare that I undertake a 300+ mile journey in the car in one sitting, but in theory with shorter daily charge cycles the battery could last another 20 years with a usable range, had it behaved in the same way as the original pack supplied new with the car 7 years previously. I paid full price for the 3.0 upgrade (circa £21,000) and my original battery was still in a good state of health, but I figured that this was a reasonable amount to preserve the car for as long as possible and there was no guarantee of the 3.0 battery continuing to be available in the long term. Others with older or higher mileage cars had a more pressing need to replace their packs and some were in the fortunate position to be able to choose between a free replacement standard pack or a very cheap 3.0 upgrade, due to the car originally being purchased with the Battery Replacement Agreement (BRA). Of course, given the opportunity to get a long range battery for just a few thousand dollars/pounds/euros, everyone I know of with the BRA has taken that option.

It was therefore very concerning that shortly after I had the 3.0 pack installed, stories started circulating on the forums that early 3.0 customers were seeing excessive degradation in their packs’ capacity.

The Roadster’s pack state of health is measured by a value called CAC (Calculated Amp-hour Capacity) and on the original Roadster pack this started at 160. As the cars age or are subjected to charge cycles, this number drops. The pack getting out of balance will also cause this number to drop and so it is possible to correct that a little. An older, high mileage Roadster today might have a CAC of around 125 to 130, so a drop of 30 to 35 points from new.

With a 3.0 pack the CAC starts at 215.04. For reasons I shall come onto, the community expected the CAC to drop at a lower rate than with the older pack, so it was disappointing when reports started to come in of packs dropping by 15 points only 9 months after installation. At first it was thought this was down to faulty packs, but soon it became clear that others were following the same trend. A fellow owner in the US collected copies of the cars’ log files to record the trend and the evidence is shown in Figures 1-3: It can be seen that the three oldest cars in the dataset, North American VINs 33, 181 and 670, have all lost 30 CAC points in less than 18 months – regardless of mileage – and that most of the others are trending the same way. This is a huge drop, many of the original packs have not dropped this much in 7 or more years and the ones that did have typically driven 3 times the distance of the highest mileage 3.0 car. Additionally, Figure 4 shows a comparison between two older, original chemistry packs and a new 3.0 pack for the same car, VIN 670. It can be seen that the same car covered more than 3 times the mileage on the old pack as the 3.0 pack with less degradation.

What is more concerning is that the gradient of the downward trend seems not to be abating. It is normal for lithium chemistry batteries to have a noticeable drop in the first few charge cycles, but we are well beyond that here. If the line continues, we can expect to see the first 3.0 cars drop below the 160 CAC of an original car in around another year from now (less than 3 years after installation) and typically catch up and overtake the degradation of most original Roadster packs before the 3.0 packs are 5 years old. The irony here being that owners who paid a sizeable proportion of the value of their cars to prolong their lifetime may have actually doomed them to a premature death.

The Roadster 3.0 packs use a modern, high density lithium chemistry not unlike the packs in the Model S and X to achieve a capacity close to 80 kWh. This was thought to give better longevity than the original “LCO” chemistry from 2006 which really was taken directly from laptop PC technology. Because of this, and the fact that in daily use the cars would have a much shallower charge-discharge cycle, it was expected by everyone that the new pack would outlast the original and thus was a good investment. Right now there are several owners who I know regret making this upgrade, others who have stated they are holding off getting it until we have more data and many more who ask me directly in person or via the forums whether they should place an order. To the latter group I honestly have to say no – wait until we understand what is going on.

Furthermore, we have reason to think that the CAC and thus range displayed may be overstating the true capacity. I and others have experienced the 3.0 pack going into the trickle charge / recovery state at a much higher level than previously – with 35 miles ideal range left in range mode, I have witnessed trickle charging to above 40 miles before returning to a normal higher current. This effectively means the pack capacity is less than claimed, as repeatedly doing this will lead to pack damage and risks running out at the side of the road.

Tesla could assist by telling the community what they know about the cells and what they think might be happening. We are fairly sure that these are LG cells – thanks to a press release that LG Chem was supplying Tesla put out prior to the release of these packs – but we do not know which cell it is and precisely which chemistry it is. There are discussions going on in the Model S/X community about premature degradation happening in some of their packs, which we understand has also been communicated to Tesla, and the suspicion is that this is a similar chemistry (albeit a different manufacturer). That is why I said this issue is relevant to the customer base as a whole. However, it is also entirely possible that this is a phantom effect caused by either the packs not balancing properly, a bug in the CAC algorithm when it was modified for the 3.0 firmware, or a combination of the two. We would therefore like to know the following:

• Which cell is used in the 3.0 pack? What is its chemistry and what is its capacity? How much of the capacity is available to the car?
• At what state of charge level does the pack start to balance? Does it balance when the owner does only a standard mode charge (which now goes to a lower state of charge than before)? Does one have to do a “full to empty” drive to trigger a CAC recalculation, as obviously that is harder with a large pack?
• Please communicate the best charging regime for the 3.0 pack, as there is conflicting advice from both outside and within Tesla on how to preserve its longevity while allowing proper balancing.
• Is Tesla corporate aware of this issue? What level of life testing was done on the 3.0 packs before release to customers? Has this type of degradation also been seen in internal testing?
• If this is a bug in the algorithm, can we expect a software update to fix the issue and give owners and perspective owners of the 3.0 pack the confidence that their pack has the capacity and longevity we expected when it was announced and when we bought it?
• If this is a real problem with the cells chosen for the 3.0 pack, how will Tesla ensure that customers are not left with severely degraded range and power in a few years after what in some cases is a substantial investment? In the worst case scenario, will the company stand by some of its most loyal customers and replace these packs with a cell type that is known to be resilient?

This issue, including the attached graphs, have been communicated to staff in service centres both in the US and the UK. So far, no owner has had a response about it.

It should be noted that in my individual case, my 3.0 upgrade was delivered with an abnormal CAC of 206. This can also be seen in the attached graphs. It was returned to the service centre in Gatwick and, after what appears to have been a firmware reload, the CAC was reset to 215.04 like the others. This is a separate issue to the large drops seen by the rest of the group, and appears to have been a one-off, however at the time of writing (after approximately 1,500 miles and 6 months), that CAC has dropped to 212 and therefore is also on track to show similar larger drops as the car is used more in the summer. It can be seen from the attached graphs that my car is following a similar gradient since the reset.


PEM Problem Costs and Related Issues

The second point which I wished to raise on the Clubhouse evening was the following: In addition to problems affecting the 3.0 packs, all Roadsters have several known Achilles’ heals which result in quotes for expensive fixes. One of the most common is the “BSM Isolation Fault”, also known as red ring of death. In this scenario the car detects an isolation fault and will not charge (it can also happen while driving but this seems to be less problematic). Having first seen the problem 3+ years ago, I and other owners have learned the trick to deal with it, but when I asked for it to be resolved at a service, I was told I needed a whole new Power Electronics Module (PEM) at $10,000. I know that I am not the only one being quoted that kind of repair cost.

Another regular problem is the “DMC Fan Error” type. These can strike intermittently but can plague the car when they do. They are typically a debug only message, but in non-debug mode will eventually show a message telling the driver there is a powertrain error and he/she should go to Service. Various reports have stated this results from a burned out fan connector that can result in Tesla again requiring the customer to replace the $10,000 PEM, but in my case I was told I needed a replacement CIC board at £1700. What is strange is that this was after the 3.0 upgrade where I am told the CIC board is replaced and therefore would be under warranty.

There is a general point here which is that the default option for many faults on the car seems to be to replace the PEM or a major subsystem of it. We have heard stories of service centres (not in the UK) suggesting a $10,000 PEM change for a blown fuse. This is obviously unsustainable for both the customers and Tesla’s supply of PEMs. Furthermore, if one were to spend this amount of money on a (typically refurbished) PEM, there is no guarantee the same fault will not happen again in 12 months because, as seen above, they happen across the fleet and therefore are intrinsic to the design.

The next issue that is starting to appear is the need to refurbish the heat sink compound on the IGBT power transistors and sometimes the IGBTs themselves. Again, on one occasion I have had an error that these were failing and was told it needed a new $10,000 PEM, but I waited to see if it would recur and it has not been back since. Sometime it is just a matter of clearing debris from the cooling channels in the PEM with an air line – a lot cheaper than the alternative.

Many owners are taking matters into their own hands. For example, the fan connector that is mentioned above as needing a $10,000 PEM replacement can be bought from online electronics retailers for around £7. One owner who needed to replace IGBTs got it done for a few hundred Euros in a Hi-Fi repair shop and still others have done it themselves. There is a small aftermarket repair industry growing up around the car, but they have had to learn most of what they do through trial and error.

As a minimum, Tesla should offer services to repair the electronics at a component level. We appreciate that this is not necessarily practical at a service centre (although technicians do their best to help), but should be at a country or a more regional level. It simply isn’t reasonable to expect owners to have to pay a 5 figure sum for what should be a minor repair to the circuit board with a commodity component. It sends a very strong negative message about the affordability and sustainability of EVs if 7 or 8 year old cars are requiring this kind of repair cost, not to mention the e-waste problem of otherwise perfectly good circuit board ending up in the skip. (And yes I have seen skip loads of components being thrown away for often minor issues, and sometimes I have witnessed owners take these parts and repair them for themselves.)

Furthermore, we appreciate that the Roadster is and always will be a low volume car which is an ever-decreasing percentage of the Tesla fleet. Retaining the skilled technicians necessary to work on it becomes ever harder to justify as stores and service centres gear up for Model 3. We understand that – and ultimately it is the outcome we want to see for the company – which is why many Roadster owners suggest that if Tesla was to open up the software, service manuals and schematics for the car it would be a win-win scenario for everyone. After all, the Roadster’s technology is 10 years old and many generations behind the Model S, X and 3. Even the components it uses are behind the state-of-the-art in terms of efficiency and power handling. There can be nothing to be gained by keeping the information proprietary – yet it would benefit the typically very technical owner community and the aftermarket repair community enormously while reducing the load on Tesla’s service organisation.

As the other models of Tesla age, this is going to become an increasing problem which will have to be dealt with in ever increasing volumes, especially with the even tighter degree of integration that those cars have. It makes sense to once again use the Roadster fleet as pathfinders in this respect.


Conclusion

In conclusion, it is clear that there is a battery degradation issue effecting the 3.0 pack installed in Roadsters since summer 2016. This is causing concern amongst the owners’ community, both with those that have paid a considerable sum to install the battery and those owners who are holding back from ordering the upgrade while their original packs continue to age.

Furthermore, there is increasing evidence that several aspects of the Roadster’s design are causing the failure of relatively cheap components to require the replacement of whole systems and subsystems at considerable cost, through company policy preventing service centres to legitimately work on them.

We therefore urge you to consider both of the above issues carefully in light of the effect they are having on some of Tesla’s most loyal and ardent customers, and we hope for a full explanation from the company about the issues we are seeing with the new 3.0 battery in particular and other repair costs in general.


Yours sincerely,

David Peilow

Countersigned by the following owners (Names or TMC usernames, with VINs where known). Many are 3.0 owners; the others have stated they are awaiting further information on the issues raised:

Alexander Sims
Dominik Westner
@eugenel
@dhrivnak
@Msjulie
@ggr
@gregd
@slcasner
@Mitrovic
@bolosky
@Peter.h
@Kerios
@rickpoisson
@thefortunes
@Nvbob
@Rolf68

 

[Kerios]

Obviously you know I’ll sign it too.

Figure with the snow etc and little use over winter I’ll be seeing similar drops in CAC now to sub 199 after 9 months which sucks.

 

[thefortunes]

Not a 3.0 owner (waiting to see what the real issue with the battery is) but since you delve into the PEM issues and release of information that would be invaluable you are certainly welcome to add my name.

 

[ggr]

I did a long drive a week ago on a range charge, and will do another one (San Diego - downtown LA and back) and will update my data after that.

 

[Nvbob]

We seriously considered the 3.0 but, along with others on this forum, had serious concerns of the cell degradation. Our present stock ESS is holding steady at about 12-15% loss after a solid seven years.

Put us down as signing also, please!

 

[gregd]

Nicely done. One nit... I think the word should be "systemic" not "systematic" in this (at least, on this side of the pond):

Furthermore, if one were to spend this amount of money on a (typically refurbished) PEM, there is no guarantee the same fault will not happen again in 12 months because, as seen above, they happen across the fleet and therefore are systematic to the design.

Do you think it would help to identify our car VINs?

Thanks for doing this!

 

[hcsharp]

Waaaaaay too long. If you want to get somebody's attention it needs to be less than one page.

 

[slcasner]

Sorry to say, David, my first reaction was the same as Henry's. I suggest that you be very brief in the introduction and limit to just the battery concerns in this letter. If you find traction, then go back for the PEM.

 

[dpeilow]

Do you think it would help to identify our car VINs?

Good idea, if we can get enough of them.

Waaaaaay too long. If you want to get somebody's attention it needs to be less than one page.

I was waiting for the too long comments. I figure that it's a single shot to get both issues across his desk, that discussing snippets hasn't worked in the past and sometimes if a person can be bothered to write a detailed letter they must be sufficiently bothered about the issue. I was also told in the discussion to detail everything.

I have made a more explicit conclusion section for the tldr brigade.

 

[JRP3]

Maybe start off with a quick summary of the issues and then go into the details.

 

[Rolf68]

Great initiative. I don't have the 3.0 upgrade but I'm agreeing with all you say about too costly PEM repairs. If that helps you can add my name to the signatures list.

Best regards

 

[ggr]

North American VINs 33, 181 and 670, have all lost 30 CAC points in less than 18 months – regardless of mileage – and that most of the others are trending the same way. This is a huge drop,

Add that this is about 14%, more than most Roadsters with original batteries have degraded.I think expressing it as a percentage makes it easier to grasp.

 

[dpeilow]

Add that this is about 14%, more than most Roadsters with original batteries have degraded.I think expressing it as a percentage makes it easier to grasp.

I thought about that, but I think absolute terms is better - as that translates into exact miles. In percentage terms the bigger battery actually makes it look less bad.

 

[bolosky]

I thought about that, but I think absolute terms is better - as that translates into exact miles. In percentage terms the bigger battery actually makes it look less bad.

Did you include this graph that shows the three batteries in my car that I'd posted a while back? It makes that point nicely, I think.

 

[bolosky]

Number 2 seems to be the outlyer here, but it looks like it hasn't been driven enough to recalculate.

Exactly right. #2 has only 109 miles on the 3.0 battery (and 4K miles on the car), and hasn't gotten even 0.1 miles for the last 195 days in the log. It seems like the CAC algorithm doesn't run at all when the car isn't driven. Most likely, if someone took it out for a drive the CAC would plummet after. We've seen that in other cars.

 

[dpeilow]

Did you include this graph that shows the three batteries in my car that I'd posted a while back? It makes that point nicely, I think.

View attachment 284428

Not yet but I will do.

Most likely, if someone took it out for a drive the CAC would plummet after. We've seen that in other cars.

It's interesting that my car, which has been driven if not huge distances, is only dropping slightly on CAC recalculation and on one occasion recently actually went slightly up. If it is purely a calendar life issue then by now I should have dropped 10 points.

 

[bolosky]

It's interesting that my car, which has been driven if not huge distances, is only dropping slightly on CAC recalculation and on one occasion recently actually went slightly up. If it is purely a calendar life issue then by now I should have dropped 10 points.

One thing to keep in mind about your car is that it may well be shifted right by ~70 days because of its reset. If you move your line over by that much, it's not as much of an outlier. And, your CAC hadn't been recalculated for the last 46 days in the log (it is unchanged to four decimal places). So your car is effectively only three months into the new battery. From that perspective, it's in the middle of the pack of the low-mileage cars.