3.0 Battery Longevity

[Tovar_Vanek]

Does anyone know how Tesla is rebuilding the Roadster battery packs?

Do they re-use the cases? Do they take apart the sheets in the ESS pack and replace the individual cells, or are they recreating sheets?

Is their limited and custom production capacity for this product beginning to create backlogs?

 

[simonog]

I had my battery changed about 3 months ago. Will the car's log show the time related change of CAC or did I need to be noting it periodically?

As I am in a more temperate climate than you Californians, if the logs contain the data it might give us a clue on the temperature dependency of the decline.

 

[bolosky]

I had my battery changed about 3 months ago. Will the car's log show the time related change of CAC or did I need to be noting it periodically?

There's not a specific notation for it in the log, but it's incredibly obvious. The log has a permanent once/day CAC measurement, and when you upgrade it goes from 150 (or wherever it was) up to 214. You can't miss it.

Go back and look at post #15 in this thread where I posted the CAC for my car for its whole lifetime and see if you can spot the upgrade.

 

[Tovar_Vanek]

What was the original life projection of the Roadster batteries. They are pushing 10 years now.

 

[snd92]

Tesla did offer battery replacement within 7 years as a package when buying the Roadster for the first owner. Either Tesla didn't believe in their batteries or it was offered to please sceptical owners...

 

[thefortunes]

What was the original life projection of the Roadster batteries. They are pushing 10 years now.

My recollection is an estimated 70% capacity after 5 years/50k miles. Someone may have a better recollection than I

Based on Tom Saxton's survey Roadster batteries are doing far better than that. For example, mine at 77k miles has ~ 13% capacity loss.

 

[dhrivnak]

Tesla did offer battery replacement within 7 years as a package when buying the Roadster for the first owner. Either Tesla didn't believe in their batteries or it was offered to please sceptical owners...

I really think the battery replacement was to appease skeptics

 

[slcasner]

My recollection is an estimated 70% capacity after 5 years/50k miles. Someone may have a better recollection than I

Based on Tom Saxton's survey Roadster batteries are doing far better than that. For example, mine at 77k miles has ~ 13% capacity loss.

The battery lifetime was specified as 7 years or 100K miles, which I find in a presentation by JB in 2011 and other sources, hence the 7-year term of the battery replacement policy. My recollection is that the definition of lifetime was 80% at 7 years, but I didn't find a source for that in the papers I have. In any case, the battery survey results are still better than that.

 

[bolosky]

Adding ggr's #537. It's interesting because it's got both the longest time and lowest mileage of any of the cars in the dataset. It's interesting because it seems to have big jumps down in its CAC, much more than the other cars do (though #33 also did to a lesser extent). Maybe that's related to not driving it very much. It's got a little less degradation than #33, the next oldest one, but that's also just one more step down of similar size to what it's seen before.

 

[ggr]

Yeah, our driving profile is pretty aberrant. We both work from home, so there is very little daily commute. Most drives are just a few miles, to/from shops or doctors (getting old sucks), with the occasional four hour range-mode drive in the desert or to LA and back.

 

[dpeilow]

Tesla did originally say 5 years / 50,000 miles = 70% capacity.

A Bit About Batteries

 

[dhrivnak]

Tesla did originally say 5 years / 50,000 miles = 70% capacity.

A Bit About Batteries

Yes and fortunately the batteries have held up much better than the earlier estimates like 12% reduction over 7 years.

 

[ViperDoc]

Tesla did offer battery replacement within 7 years as a package when buying the Roadster for the first owner. Either Tesla didn't believe in their batteries or it was offered to please sceptical owners...

I am one who bought the replacement battery early. I recall being told I should be able to get to 7-10 years with 70% if I treat the battery well (e.g., not always full charging, not driving in performance mode all the time, etc). I think the reason they offered the deal was to get extra money at a time when they needed every nickel they could muster. As I recall, they basically pre-sold you the next battery at about half the cost it was at the time. If you replaced the battery at 7 years, you were even. For every year prior to 7 years that you replaced it, you owed then $2000 more. For every year after 7 (up to 10 years) you replaced it, they refunded you $1000. They portrayed it as a way to lock in the battery price, which they expected to drop significantly, but who could be sure—it was sort of an "insurance" policy, but as I have noted, I suspect part of it was a way to bring in more money at that point in their development/growth at a relatively low risk to themselves (if things worked out the way they hoped).

 

[hcsharp]

I am one who bought the replacement battery early. I recall being told I should be able to get to 7-10 years with 70% if I treat the battery well (e.g., not always full charging, not driving in performance mode all the time, etc). I think the reason they offered the deal was to get extra money at a time when they needed every nickel they could muster. As I recall, they basically pre-sold you the next battery at about half the cost it was at the time. If you replaced the battery at 7 years, you were even. For every year prior to 7 years that you replaced it, you owed then $2000 more. For every year after 7 (up to 10 years) you replaced it, they refunded you $1000. They portrayed it as a way to lock in the battery price, which they expected to drop significantly, but who could be sure—it was sort of an "insurance" policy, but as I have noted, I suspect part of it was a way to bring in more money at that point in their development/growth at a relatively low risk to themselves (if things worked out the way they hoped).

I agree it was primarily for raising capital. I don't think it did anything to appease the skeptics because it only confirmed that the batteries will need an expensive replacement in a few years. I bought it because it looked like I would get a good return on my investment, not because I was skeptical or worried about anything.

 

[ion_1]

I vote to put this thread focused on bolosky's data gathering as a sticky, both as a reminder for data updates/uploads and also quick reference. It may be one of the most import and broadly impactful threads moving forward...

 

[Volta]

I am about to take re-delivery of my Roadster (2.5 Sport) with a 3.0 battery on 1 August. I live in Hong Kong (climate: hot and humid most of the year). I do not have a garage, but most weekdays the car will be garaged in my office complex. I will drive daily, around 70-80 kms round trip to the office and back, and charge whilst at the office at 10 amps.

Happy to contribute my data, if this would be helpful, after I have driven for a couple of months or so.

Any tips on how to try to maintain my battery in best condition? I have taken the 3.0 as a replacement for my failing original battery. I recently had to replace one sheet, but shortly after 2 other sheets failed. I figured it was a better bet to replace the battery than another 2 sheets at that point, as I had lost confidence in the original battery, and in the longer term I hope the new battery is a more cost effective option.

I would note that I am the second keeper of my Roadster, and so I do not know how well the car was maintained by its first keeper. My battery issue might be a consequence of the life it led originally, or that fact that the Hong Kong climate is unkind to battery longevity. owner of this Roadster, or something else entirely.

Thanks, all.

 

[hurd300403]

just pulled my logs for the first time today. got the data exported to a .txt file. now... who do I send it to to be added to the graph?

 

[bolosky]

Here's the latest data, adding hurd300403's #1341, which is interesting because it's by far the least driven car. It looks really good on the CAC vs. time chart, but given that the other low-mileage cars (like #537) have big jumps down when they're driven, I wouldn't be surprised if this happened to his car eventually, too. I also added in more data for Dave Denhart (#181) and me (#670). The flat spot that I had for a few thousand miles made me hope that I'd hit the knee in the curve, but it looks like it's back to dropping at about the same rate as before. I guess we'll have to keep watching to see what happens.

 

[gregd]

Thank you for posting this update! I'm still holding on doing the upgrade, waiting (hoping) to find where the cars really do stop dropping. But I'm getting nervous... My CAC has dropped from 141.9 to 139.3 in just the past 6 months.

 

[ion_1]

Truly, thank you to Bolosky and those who contributed for the update. Due to the SiOx /graphite based negative electrode (vs graphite used in the original cells), these should start to noticeably level out at appreciably at approx. 15% loss (approx 185 Ah). You all have a little bit more to go before all of us start to become a little stressed or very happy. This trend in upfront loss is how individual HG2 cells behave based on published testing data I have seen. Your plot is incredibly helpful. So critical to track for those who bought 3.0, those pending purchase, and Tesla themselves.

IMHO I still think this thread should be a sticky...