Kevin Sharpe's decreased Roadster range

[djp]

A little late to the game here, but seems to me that a simple solution would be to replace the brick with either new or refurb. Any word from Tesla as to how much that would cost?

The individual bricks can't be replaced, they're glued into sheets of nine bricks each. A sheet should run around $4K (with the pack around $40K), but I don't think anyone has seen a recent quote from Tesla.

 

[djp]

Tesla battery range degredation forcing return to gas

I'd be happy if Tesla just identified and spelled out an acceptable capacity loss number for miles/time. The lack of such guidance is an issue.

They did publish guidance in their 2006 technical blog, but it's not in the warranty. Expected degradation was 30% after 50,000 miles over five years. This was the range that original Roadster buyers were expecting, and in practice the packs have been performing much better than that. Kevin's car is an outlier compared to other Roadsters, but well within Tesla guidance.

A Bit About Batteries | Blog | Tesla Motors

As batteries in any EV age, they lose capacity and the vehicle will lose range. This is unavoidable and true in any EV with any type of battery. You can think of this as a very slow reduction in the volume of your vehicle’s “gas tank” over its lifetime. We limit how fast this aging and loss of range happens by working very hard to select the best cells, design the best cooling systems, and carefully manage charge states. By doing all of this we expect more than 100,000 miles of driving range and more than five years of useful life. However, at the end of this period the pack will have less capacity than when new (just like an internal combustion engine has less power and much worse emissions than when new). If, for example, you drive 10,000 miles per year at the end of five years you will have around 70 percent of the energy storage capacity of when new. This performance gives the Tesla Roadster battery pack the best range and lifetime combination of any production EV battery ever built.

 

[apacheguy]

IMHO, their guidance is too restrictive. 1/3 of the capacity lost after 50 K? If all electrics exhibited that degradation curve, well, I'm sorry but the future would be pretty bleak. But as you correctly point out, that amount of degradation is not representative of the fleet of roadsters. It's very easy to warrant the battery for degradation and come up with some outlandish figure that nobody is ever likely to see. Again, IMO, 30% is outrageous.

 

[bonnie]

Wait, what? They state it publicly in 2006, and you don't like the number now in 2014 so it's outrageous? How does that work?

i can see disagreeing with their conclusions ... But isn't it their right to set the limits? This information has been out there publicly since 2006. Don't buy the product if you don't like what a company says - but buying it and then saying they were outrageous seems illogical. I don't understand your reasoning.

 

[wiztecy]

Again, IMO, 30% is outrageous.

Don't forget what the Roadster was back then, the true roots of it. Also don't forget what Tesla was back then, a company doing the unimaginable. There was tremendous risk involved releasing a car that was the bleeding edge of technology. It was essentially borderline of a prototype, hence being hand built. I don't feel 30% is outrageous over 5 years. Tesla had to limit risk as much as possible to survive, but they also had the obligation to offer the customers a great experience and confidence back then which I believe they relayed. If Tesla was too generous, they easily could have failed like Fisker and then these Roadsters would have *Zero* support from then on.

Buying any new cutting edge technology always has risk, subject to failure and full loss of its value as well as functionality if the business and its business plan is not executed efficiently and effectively. As a new business I feel that was a fair and appropriate condition for the warranty.

Tesla has shown to be even more generous with their Model-S warranty. This is due to the technology maturing, more cars being sold, and in turn the risk becomes diluted for Tesla.

 

[pharma5]

The Plug In America Battery Survey (here) shows a 21 mile decline in range in the last year...

So this is really a problem in the last year, right? Until your most recent 10,000 miles, your data were right in line with the PiA trendline.

Even now at 159 ideal miles on std charge, there were people who hit a similar mark at lower ODO mileage in the survey (circa 48,000-50,000 and even 20,000).
The overall capacity is also still better than the non-warranty projection from 2006 (82% vs. 70%).

It remains to be seen if your pack will plateau near 159 and come back to trend, or drop off a cliff, but only driving it will tell you that.:frown:

Manual markup of the PiA chart looks like:

 

[apacheguy]

Wait, what? They state it publicly in 2006, and you don't like the number now in 2014 so it's outrageous? How does that work?

i can see disagreeing with their conclusions ... But isn't it their right to set the limits? This information has been out there publicly since 2006. Don't buy the product if you don't like what a company says - but buying it and then saying they were outrageous seems illogical. I don't understand your reasoning.

Yes, it is correct to set limits, but yes, I am disagreeing with that limit. That's all I'm saying. And furthermore I don't own a roadster. I was merely remarking that 30% after 50 K miles for a liquid cooled pack seems unfair.

But yes perhaps I did not have the appropriate context given that this was something written back in 2006 and was discussing cutting edge tech. That's a fair point, wiztecy.

 

[pharma5]

They did publish guidance in their 2006 technical blog, but it's not in the warranty. Expected degradation was 30% after 50,000 miles over five years. This was the range that original Roadster buyers were expecting, and in practice the packs have been performing much better than that. Kevin's car is an outlier compared to other Roadsters, but well within Tesla guidance.

A Bit About Batteries | Blog | Tesla Motors

belated +1.

edit: 'though i'm not sure it's an outlier....yet

 

[slcasner]

Yes, it is correct to set limits, but yes, I am disagreeing with that limit. That's all I'm saying. And furthermore I don't own a roadster. I was merely remarking that 30% after 50 K miles for a liquid cooled pack seems unfair.

I believe the 30% loss is due to 5 years of calendar lifetime, not 50K miles of cycle lifetime. Note that the quote speaks of going 100,000 miles in the same time if you drive 20K per year instead of 10K.

 

[AEdennis]

They did publish guidance in their 2006 technical blog, but it's not in the warranty. Expected degradation was 30% after 50,000 miles over five years. This was the range that original Roadster buyers were expecting, and in practice the packs have been performing much better than that. Kevin's car is an outlier compared to other Roadsters, but well within Tesla guidance.

A Bit About Batteries | Blog | Tesla Motors

Seeing that there is guidance and an expected drop of 30% after five years and/or 50,000 miles, I guess my CPO is doing pretty good at 3 miles (vs the fifteen that started my thread on this site a few months ago). However, they also provided a CPO Purchaser with a new 37 month, 37,000 mile warranty, so I wonder if they really should adjust this projection. At least for CPO purchasers. Otherwise we got a warranty that is already out of spec from the time we picked it up (an '08 Roadster would've been five years when we bought it last year.).

Therefore it should seem that Tesla did provide guidance and Kevin's car, at this time is within the outer bands of that limit (for now...)

 

[ra-san]

I guess it's apparent there are a lot of different ways to look at and judge all this. Based on what limited info I know from this thread though, it just seems pretty simple to me. I think about what I'd think if it were my car. Seems to me, perhaps incorrectly, that it is fairly clear a particular brick in the battery is at fault, operating substantially different than the rest, and that the battery is not able to rebalance as it should and should therefore be fixed (if under warranty). It doesn't seem like normal wear when it's one piece failing consistently more than the rest of the pack - does it? From Tesla as well as posts here, I thought normal behavior was to see the pack age as a whole, with all parts of it being balanced such that no one part should stand out, unless there was a defect.

If any of the premises of my conclusion are incorrect, I'm sure it'll be pointed out, and either way I don't think there's anything more I can add, so I'll probably just sit back and observe from here on out.

 

[WarpedOne]

Seems to me, perhaps incorrectly, that it is fairly clear a particular brick in the battery is at fault, operating substantially different than the rest, and that the battery is not able to rebalance as it should and should therefore be fixed (if under warranty).

I has already been said - you can only replace with something if you have something to replace. Roadster's cells are long out of production, you cannot buy then new anymore. Tesla can only use some old already replaced pack, take out the cells and mount them into Kevins pack. This practice only goes as long as there are old pack lying around some service center.

Tesla already announced they are working on a new pack using current cells. When it is finished, people will get it. Until then a failed pack is more of a problem than a pack with a 19% degradation so it gets priority to use that old cells still in stock.

Kevin is crying because tesla does not replace his 19% degradation. Imagine his crying if tesla didn't replace his completely dead battery (because they gave those last cells to the guy complaining about 19% lost range).

 

[dpeilow]

I believe the 30% loss is due to 5 years of calendar lifetime, not 50K miles of cycle lifetime. Note that the quote speaks of going 100,000 miles in the same time if you drive 20K per year instead of 10K.

Well, my car is over 4 years old but with 13,000 miles and I am seeing nothing like this kind of loss.

 

[djp]

Tesla battery range degredation forcing return to gas

Seems to me, perhaps incorrectly, that it is fairly clear a particular brick in the battery is at fault, operating substantially different than the rest, and that the battery is not able to rebalance as it should and should therefore be fixed (if under warranty). It doesn't seem like normal wear when it's one piece failing consistently more than the rest of the pack - does it? From Tesla as well as posts here, I thought normal behavior was to see the pack age as a whole, with all parts of it being balanced such that no one part should stand out, unless there was a defect.

Kevin hasn't shared his ahr.log yet, so we don't know the state of the other bricks. We know that one is consistently low, but it could be that other bricks are close behind. The bricks will degrade at slightly different rates, so over time one will pull out ahead. That's normal behaviour and doesn't mean the pack rest of the pack isn't aging as well. We need the full distribution to see that, which is in the ahr.log.

Personally, I bought my Roadster expecting to see 30% degradation after five years and to need a battery replacement after ten (this was before the PIA study gave us some real world data). I'm extremely happy that my pack is close to its original capacity after four years, and I doubt I'll need to replace it within the life of the car (but might anyway to do the upgrade). Even if I had Kevin's level of degradation, I'd still be happy that the battery was doing better than I expected.

 

[JRP3]

Part of the issue here is that Kevin seems to regularly drive longer distances than most people, who would not be significantly inconvenienced by 19% loss of range.

 

[wycolo]

My 2.0 is approaching four years of age but @11k miles not much loss of range. Tesla did not request additional warrantee $$ from me or even suggest such afaik when my warranty expired. Kevin coughs up more than a few bucks for such and gets no respect, especially given the fact that his batt has a specific defect (that can be pointed to) rather than just gradual deterioration. Europe is overdue for a Roadster wreck which night change all this.
--

 

[JRP3]

He did know that the warranty excluded pack degradation, and though the degradation is more than he can accept it's not exceptionally severe.

 

[scaesare]

I believe the 30% loss is due to 5 years of calendar lifetime, not 50K miles of cycle lifetime. Note that the quote speaks of going 100,000 miles in the same time if you drive 20K per year instead of 10K.

Most Li-ion battery degradation curves are in reference to equivalent full-charge cycles however. So while calendar age is undoubtedly a factor, I suspect the dominant parameter is miles driven (and hence number of charge cycles), all else being equal.

 

[qwk]

He did know that the warranty excluded pack degradation, and though the degradation is more than he can accept it's not exceptionally severe.

Fair point, but on the other side of the coin, he coughed up an equvent of $21k US. Considering one could buy a new Roadster pack for around $36k a few years ago, you would think that a $21k warranty would yield better treatment of the customer.

 

[scaesare]

Seems to me, perhaps incorrectly, that it is fairly clear a particular brick in the battery is at fault, operating substantially different than the rest, and that the battery is not able to rebalance as it should and should therefore be fixed (if under warranty). It doesn't seem like normal wear when it's one piece failing consistently more than the rest of the pack - does it? From Tesla as well as posts here, I thought normal behavior was to see the pack age as a whole, with all parts of it being balanced such that no one part should stand out, unless there was a defect.

Unless, of course, it's anticipated that there can degradation that will not always be equal within in any one pack, and the system as a whole is engineered to accommodate balancing to the extent possible.

Let me ask this: if the logs showed the lowest brick toggling between a couple of bricks, and yet the total range was still within the aforementioned guidance, would it then be OK? How about 4 bricks? Or 7?

Recently within a thread on the model S pack where there are fusible links on each cell, I did some calculations that any SINGLE cell or fuse failure will likely induce a 1.35% range degradation, despite that being only 0.00014% loss of available cells in the pack. A single cell issue will force a single brick to remain low. That will in turn limit the entire pack.

Knowing that when you have thousands of items you will have some variance, and then specifically setting expectation for that variance as well as degradation in addition to specifically excluding it as a warranty item, it doesn't seem fair to qualify that as a failure.