Standard Warranty Revealed

[Yggdrasill]

If you assume the battery prices go down (not unreasonable, of course), the battery leasing prices will go down as well. Or people will start buying third-party batteries at the end of their battery leases.

But we're getting a bit away from the issue. The issue is not the specifics of the comparison with Renault, the issue is that Renault can and does offer better terms for battery capacity.

The fact is that if the Model S 85 kWh battery can easily last 200,000 miles/8 years, like Elon Musk says (he's said the batteries are expected to last around twice what they are warrantied for), the additional cost of providing a specific warranty for 70% capacity at 8 year/200,000 miles is $0.00. As no battery will be replaced, there is no cost. Why wouldn't Tesla want to offer superior terms at no additional cost?

This doesn't make sense unless you believe the guys at Tesla to be utter morons, or, that you accept that they assess the added sales due to the better terms doesn't outweigh the risks/costs of having to replace X batteries. This means that you have absolutely no guarantees that the battery you buy will last 200,000 miles with at least 70% capacity. In fact, Tesla expects that there's a significant chance that a significant amount of batteries won't last that long. That is what their actions are saying, at least.

 

[Bearman]

Ygg: The zoe will cost you 36,500 usd for 8 years and 96,000 miles with the (75%) warranty and a 12,000 mile yearly range.
[21,000 usd upfront and 1,918 usd per year (12,000 mile/year milage) x8 years for the battery lease, uk prices]
I think that's all good.

Renault have said that they expect the usable battery life to be 8-10 years, also there are many constraints in the actual contract

4.2.1 No amendment may extend the Maximum Contractual Mileage beyond 120,000 miles.
4.2.2 No amendment may extend the Period of Hire beyond 72 months.

http://www.renault.co.uk/Resources/PDF/batteryterms.pdf

Another thing to contemplate is what if Renault would have the same apply for a 85 kwh battery, what would they charge?
Assuming a battery twice as large would cost about twice as much and hence the lease cost would be doubled as well, would it be (85/24)*[lease cost of the 24kwh battery]?

Lets see, if we use the 18,000 yearly mile number from your link that's 2,477 usd/year (133 GBP/month* exchange rate(1.55)*12) . Multiplied by (85/24), times 8 years = 70,195 usd.
Added to that you have the cost of the car itself.

Battery lease is a good option and the warranty is reassuring but it's not without constraints, there is no free lunch.

 

[VolkerP]

Why wouldn't Tesla want to offer superior terms at no additional cost?
[...]
In fact, Tesla expects that there's a significant chance that a significant amount of batteries won't last that long. That is what their actions are saying, at least.

I beg to disagree. This is not a zero cost option. Tesla's actions say, "TM doesn't bear the risk to warrant any remaining battery capacity in all and every car, since we would have to deal with many warranty claims in cases of battery neglect or [inadvertent] battery abuse." I support that. There would be considerable amount of money involved in that and I don't want to have that added to my Model S purchase price.

 

[Adm]

Warranties cost money, period. Every warranty is backed by an insurer as no new, small business can take that kind of risk. Tesla would have to add the premium to the price.

 

[VolkerP]

BTW we are far off topic. The battery lease thread is here: A Battery is Expensive - so, Lease
I searched for a thread dedicated to the Model S battery warranty, but there appears to be none.

Mods, care to move posts / spawn new thread?

 

[Yggdrasill]

I beg to disagree. This is not a zero cost option. Tesla's actions say, "TM doesn't bear the risk to warrant any remaining battery capacity in all and every car, since we would have to deal with many warranty claims in cases of battery neglect or [inadvertent] battery abuse." I support that. There would be considerable amount of money involved in that and I don't want to have that added to my Model S purchase price.

There's nothing to stop Tesla for adding a few reasonable demands to avoid abuse. For instance:

- Usage of supercharger for no more than 10 times a week.
- No longer than one week between being plugged into a socket with at least 1 kW output for at least 10 hours.
- Battery left at greater than 90% charge for no more than 10% of the time.
- Battery left at less than 10% charge at no more than 10% of the time.
- Battery never left at more than 40C or less than -20C for longer than 72 hours with the thermal management system off.
- etc.

This is a lot better for everyone, as everyone knows the rules. Not like now where Tesla decides if something is a defect or not, and replaces/repairs the battery only if they are in the mood to do so.

 

[VolkerP]

You get more battery capacity loss from sitting 5x at 39C than once at 40C. You get even more loss from sitting frequently at 35C. It is nearly impossible to state the harmful combinations of time, SOC, temperature, and charge/discharge current in a warranty. If stated, it would be hard for a consumer to adhere.

The technical stopgaps, if implemented to the full extend of degradation-denying battery states, would severely cut operational windows for discharge currents (good bye Performance Model S), temperatures (good bye AZ, TX), and SOC (good bye 265 EPA range) and leave you with a rather impractical EV.

 

[JRP3]

Going from 50% to 0% doesn't take long. On the cell level a 85 kWh battery at 50% capacity is not at all like a 40 kWh battery at 100% capacity.

How so? An 85kWh pack at 50% capacity is a 40kWh pack. Most cells degrade fastest in the first 20-30% of capacity and then stabilize, so a 50% 85kWh pack may actually drop capacity more slowly than an actual 40kWh pack at 100% capacity.

 

[brianman]

- Usage of supercharger for no more than 10 times a week.

10 times seems way high for weekly supercharger use

 

[strider]

Why would they replace the whole battery pack and not just the weak brick ? I thought that was the point of a modular design like this ?

They do that to get your car back on the road quicker. What they actually do is give you a replacement battery that has the same or more capacity [discounting the bad brick(s)] then take your battery and replace the bad brick(s) and use that for the next customer who has a battery problem.

 

[strider]

There's nothing to stop Tesla for adding a few reasonable demands to avoid abuse. For instance:

- Usage of supercharger for no more than 10 times a week.
- No longer than one week between being plugged into a socket with at least 1 kW output for at least 10 hours.
- Battery left at greater than 90% charge for no more than 10% of the time.
- Battery left at less than 10% charge at no more than 10% of the time.
- Battery never left at more than 40C or less than -20C for longer than 72 hours with the thermal management system off.
- etc.

This is a lot better for everyone, as everyone knows the rules. Not like now where Tesla decides if something is a defect or not, and replaces/repairs the battery only if they are in the mood to do so.

No, this is WAY too complicated. People will not buy EV's because "they have too many rules". It's much better to leave it as it is, let the early adopters take some risk, and then when Tesla has more data they could add language. But it's not that much of a risk - again, we have Roadster experience here. My car is 20 months old with 20,300 miles on it driven every day. I have 96% battery capacity. I have no worries at all about buying a Model S.

 

[kevincwelch]

No, this is WAY too complicated. People will not buy EV's because "they have too many rules". It's much better to leave it as it is, let the early adopters take some risk, and then when Tesla has more data they could add language. But it's not that much of a risk - again, we have Roadster experience here. My car is 20 months old with 20,300 miles on it driven every day. I have 96% battery capacity. I have no worries at all about buying a Model S.

Strider,

How different is the Model S battery from that of the Roadster? If it is similar, I would reluctantly agree. If substantially different, I'm not sure I would agree until more data is out there.

How do you drive 20300 miles daily? ? ?? ? ?

Sent from my Transformer Prime TF201 using Tapatalk 2

 

[qwk]

Strider,

How different is the Model S battery from that of the Roadster? If it is similar, I would reluctantly agree. If substantially different, I'm not sure I would agree until more data is out there.

How do you drive 20300 miles daily? ? ?? ? ?

Sent from my Transformer Prime TF201 using Tapatalk 2

What you fail to realize is that the battery cells are made by Panasonic, and are the latest and most energy dense available at this time. The roadster cells are outdated in comparison. Now if the cells were some cheap Chinese knockoffs, then there would be reason to worry. Just look at the battery warranty of the Roadster vs the Model S. it's better for a reason.

 

[kevincwelch]

What you fail to realize is that the battery cells are made by Panasonic, and are the latest and most energy dense available at this time. The roadster cells are outdated in comparison. Now if the cells were some cheap Chinese knockoffs, then there would be reason to worry. Just look at the battery warranty of the Roadster vs the Model S. it's better for a reason.

I'm impressed you could infer that from my question...so thanks.


Sent from my Transformer Prime TF201 using Tapatalk 2

 

[qwk]

I'm impressed you could infer that from my question...so thanks.


Sent from my Transformer Prime TF201 using Tapatalk 2

Seriously, why would Tesla change the battery management significantly from the roadster if it works so well? The change from the 2.2 mah computer grade cells to the 3.1mah automotive grade cells is definately significant, but Panasonic has decades of experience with li-ion battery tech. If anybody can make a great cylinder format cell, it's Panasonic.

Most of your tech questions can be answered by reading this site. Whining without doing research is nonsense, plain and simple.

 

[kevincwelch]

Thanks for the information.

Sent from my Nexus S 4G using Tapatalk 2

 

[dmckinstry]

Why do you assume they are 'afraid'? As Jerry notes, there are plenty of reasons dependent upon driving record. How would you have them word something like that?

Well, they could say as long as the car is driven and charged within specified guidelines. Those guidelines are net yet available, but could be specified in the owners guide.

The owner would then have to permit Tesla to have access to charging and driving records via onboard computer(s). I certainly wouldn't be adverse to that. We already know some of the practices that would cause premature degradation of the battery pack. Certainly it would be adversely affected by trying to do 0-60 mph as fast as possible every time we entered an on ramp.

 

[strider]

How do you drive 20300 miles daily? ? ?? ? ?

Sorry, poor grammar. Meant to say that it's a daily driver, depended upon to get me to work and back each and every day, that it's charged every night and used in the same was that my Corvette was used when I had it.

 

[kevincwelch]

Sorry, poor grammar.

I know what you meant...:smile:

 

[stopcrazypp]

You wouldn't be disadvantaged in advertising by warranting the worst case battery capacity. If the battery capacity warranty is for 70% after 8 years/200 000 miles (and you have a defect warranty for unlimited miles/8 years), but the expected capacity is 80% at average use, you can use the 80% figure all you want in advertising, as long as the right disclaimers are added.

The worse case is definitely not 70% after 8 years/200k miles. That's actually the average case. At ~500 cycles to 70% in the average case (standard cycle testing), it's 150k, 120k, 80k miles respectively for the 300, 240, 160 mile packs respectively (assuming you get that much range from those packs on a full charge). At a 40-60% SOC storage at 25 degrees C, a laptop battery loses about 4% per year and will last ~7.5 years to 70%.
Tesla offers 8 year and similar mileage coverage for their defect warranty specifically because this represents the average case life.

Worse case is this:
The lower bound for a laptop cell is typically 300 cycles to 70%. Add the fact you likely won't get the advertised 300 miles range in a full pack (real world esp. worse case would be closer to 265 miles or under) and you get the following numbers: 79.5k, 63.6k, 42.4k for the 300, 240, 160 mile packs respectively.
In terms of calendar life, laptop cell stored near 100% SOC loses about 20% capacity per year, so in about 1.5 years your battery pack can be at 70% in the worse case. The Tesla BMS likely won't let you store at 100% SOC so let's assume worse case is 2-3x better (3-5 years like a typical laptop battery used in a laptop).

How receptive would the public be to a 3-5 year 40k/60k/80k mile warranty to cover the worse case 70% degradation? And I bet most competitors will trash this in advertising.

And in advertising you put the terms of your warranty (and if you don't, your competitors will do so for you like GM did when comparing to the Leaf's warranty), not the average use case (there may be regulations against this given I have never seen a car manufacturer do so).

As for your suggestion for all kind of restrictions on the battery usage, that's way too complicated for your average buyer.

The Renault situation is different because you don't own the battery (and as others pointed out they priced that warranty into the rental price plus they have the standard leasing restrictions to help them). Given the 36 month and 18k mile max terms on the Fluence, that's equivalent to a 3 year/54k mile warranty (you can compare to my worse case warranty and see it's quite similar).

Realistically, I don't see battery wear warranties happening for purchased batteries until the worse case degradation of typical batteries reaches 8 year/150k miles (not just the average case). This is not unobtainable given the SCiB and a123 cells.