Standard Warranty Revealed

[stopcrazypp]

Trying to warranty a specific level of wear on the battery, is like trying to warranty a specific level of wear on an engine, or a set of tires. Don't think I've ever seen that happen before.

I think this is the best answer. Because wear is highly dependent on usage, it becomes an issue how you should design that warranty. Should you warranty for the average case and take the risk of lots of costly warranty replacements (even for those only slightly worse than average)? Or should you warranty only for the worse case and then be disadvantaged in advertising (people would assume that is the average case, naysayers would assume best case).

There's also two types of wear: calendar wear (dependent on storage temperature and SOC) and cycle wear (dependent on discharge/charge rates, temperature, and SOC window).

 

[Johan]

The way the warranty is phrased is ambiguous enough that it's more likely than not that you will see court cases. If someone has 70% after 4 years/100 000 miles, that would be more degradation than one would expect, but is the battery defective?

What about the Model S taxis? A taxi can travel more than 500 000 miles in 8 years. If the battery dies before 8 years have passed, will Tesla say "The Battery, like all lithium-ion batteries, will experience gradual energy or power loss with time and use. Loss of Battery energy or power over time or due to or resulting from Battery usage, is NOT covered". Technically, they're not saying that the battery must have any energy storage capacity left... I think Tesla has really dropped the ball on the battery warranty terms. Even if Tesla is the nicest company in the world and consideres basically everything a defect to be replaced under warranty, and there's not a single issue with a single Model S battery, anyway, the warranty terms are pretty bad. They will draw a lot of negative attention, just as the Nissan Leaf warranty has drawn a lot of negative attention. (The Nissan Leaf warranty has drawn a lot of negative publicity here in Norway, at least.)

If Tesla wants to replace every fossil car with an electric car, they need to be focusing on important stuff like battery degradation, not trivial stuff like rear seat lighting and whatnot. Actually, the way Tesla has (not) handled the warranty issue makes me nervous to buy a Tesla. It seems more and more like a conscious evasion, and that they're hoping no one will notice that the warranty terms are such that you will get a new battery under warranty if, and only if, Tesla is in the mood to give you a new battery. If battery degradation is for every Model S battery greater than expected over time (something you can't quickly replicate in a lab), Tesla will back slowly away from the Model S and say "battery degradation is to be expected", and then you're out of luck. If you thought you were investing in a car that would provide you for transportation for many years, well, you were wrong.

Roadster owners have not experienced a problem with Tesla regarding needed battery replacements. So while in theory, you have a point - in practice, it's not how they have operated. You forget they have a proven track record on this issue.

I agree with both of you, i.e. I too think the if the wording in the original post about battery warranty is supposed to be all that Tesla says about battery warranty then it seems weak. On the other hand it would seem from the experiences with Roadsters that have been driven both very long and hard (and experiencing less battery degradation than expected) implies that this should not be an issue. On the other hand, the cells in the Model S battery are newer and therefore an upgraded chemistry, and the battery pack as a whole with the cooling etc. is a new design. I expect it to work well for many years, but a warranty is for the unexpected, an insurance for the consumer. Bear in mind that we are paying a lot for this car, and a whole lot of that is the battery. I would think that Tesla would/should have a "fine print" regarding what is considered normal/acceptable battery usage. Maybe not of interest for the average consumer to read but nonetheless I feel it is something that you as a consumer should be able to know before your purchase. For example, where I live many cell phone operators have monthly packages with "Unlimited calls, SMS and data" but when you read the fine print there is a "fair usage policy" that says something like: not more than 4000 minutes of phonecalls, no more than 5000 SMS, if more than 10 Gb of data then speed is reduced to 128kb/s for the rest of the month. Tesla should create their own "fair usage policy" for the car and battery. For example:
- How much can you super-charge (we know this is more of a strain to the battery)?
- Unlimited miles with the 85kW battery ofcourse means unlimited miles, but something like a taxi might be excluded under the "fair usage policy" (maybe only for personal use?)
- What if you race the car on a race track 200 days a year - is that within "normal use" (you will have a lot of charge-decharge cycles but relatively few miles)?
- An even more extreme example of "unfair" battery usage: someone (through some contraption) makes a system where you charge the battery at night (low rate) and then feed it back during peak-hours, basically the cars just sits in the garage and makes money, 0 miles but a lot of charge-decharge cycles.

Maybe miles is not a very good variable for the warranty (for the 40kW and 65kW)? Perhaps the total ammount of kW charged-decharged is a better measure? Or simpler: total number of "full" recharges?

For me I think the most important question is: How much can you Supercharge (and/or other forms of quick charge) before it voids the warranty?

 

[pguerra]

Aside from the ambiguity with the battery warranty, I think the report from this S owner is pretty positive overall. And I'm a pretty hard sell.

Edit: Thanks for the repost Brianman/OP.

Yes overall it's a little on the positive side. So what does "unlimited miles" mean on the 85kw battery warranty?

 

[brianman]

So what does "unlimited miles" mean on the 85kw battery warranty?

Upper limit calculation below.

Assuming your efficiency is identical to that of driving 55 mph steady, you eat+drink while driving, and you relieve+sleep while recharging...

Consumption
55.00	miles/hour
300.00	miles/charge
5.45	hours/charge
Charging
24.00	hours/day
4.72	hours/charge
Continuous Usage
10.17	hours/cycle
2.36	cycles/day
861.84	cycles/year
6,894.75	cycles/warranty
2,068,426.04	miles/warranty

 

[CapitalistOppressor]

IANAL, but I believe that battery degradation that is markedly worse than standard profiles would, absent some proof of negligence to the battery, be covered under the warranty under normal interpretation of US law. The only way that a battery could degrade so much more quickly was because it was defective.

^^ There is no court in the U.S. that would accept a massively degraded battery over the course of a year as anything less than a defect, unless Tesla could prove abuse. It's more of an open question as to what happens if you are at 60% in your 8th year.

 

[CapitalistOppressor]

The way the warranty is phrased is ambiguous enough that it's more likely than not that you will see court cases. If someone has 70% after 4 years/100 000 miles, that would be more degradation than one would expect, but is the battery defective?

What about the Model S taxis? A taxi can travel more than 500 000 miles in 8 years. If the battery dies before 8 years have passed, will Tesla say "The Battery, like all lithium-ion batteries, will experience gradual energy or power loss with time and use. Loss of Battery energy or power over time or due to or resulting from Battery usage, is NOT covered". Technically, they're not saying that the battery must have any energy storage capacity left... I think Tesla has really dropped the ball on the battery warranty terms. Even if Tesla is the nicest company in the world and consideres basically everything a defect to be replaced under warranty, and there's not a single issue with a single Model S battery, anyway, the warranty terms are pretty bad. They will draw a lot of negative attention, just as the Nissan Leaf warranty has drawn a lot of negative attention. (The Nissan Leaf warranty has drawn a lot of negative publicity here in Norway, at least.)

If Tesla wants to replace every fossil car with an electric car, they need to be focusing on important stuff like battery degradation, not trivial stuff like rear seat lighting and whatnot. Actually, the way Tesla has (not) handled the warranty issue makes me nervous to buy a Tesla. It seems more and more like a conscious evasion, and that they're hoping no one will notice that the warranty terms are such that you will get a new battery under warranty if, and only if, Tesla is in the mood to give you a new battery. If battery degradation is for every Model S battery greater than expected over time (something you can't quickly replicate in a lab), Tesla will back slowly away from the Model S and say "battery degradation is to be expected", and then you're out of luck. If you thought you were investing in a car that would provide you for transportation for many years, well, you were wrong.

Negative speculation, heaped on negative speculation. Battery technology is what it is. Nobody is going to warranty degradation until we have years of experience with it. But there are a large number of issues that can happen with a battery that have nothing to do with degradation, and that IS covered under the warranty.

 

[CapitalistOppressor]

Yes overall it's a little on the positive side. So what does "unlimited miles" mean on the 85kw battery warranty?

Just what it means. I would presume that the warranty does not cover commercial use, but for personal use you can drive to the moon and back and still be in warranty.

The practical reason that Tesla can provide a better warranty for a larger battery is that you substantially reduce the number of required charge cycles to drive the same distance. That by itself extends the life of the battery substantially. And I am guessing that Tesla is getting the rest of the way to "unlimited" with the cynical realization that you likely can't drive a million miles in 8 years with charge times being what they are. Especially when you consider that extensive use of SuperCharging probably voids the warranty.

 

[CapitalistOppressor]

Upper limit calculation below.

Assuming your efficiency is identical to that of driving 55 mph steady, you eat+drink while driving, and you relieve+sleep while recharging...

Consumption
55.00	miles/hour
300.00	miles/charge
5.45	hours/charge
Charging
24.00	hours/day
4.72	hours/charge
Continuous Usage
10.17	hours/cycle
2.36	cycles/day
861.84	cycles/year
6,894.75	cycles/warranty
2,068,426.04	miles/warranty

LOL. Yes, I suppose that since you avoided SuperCharging that would be covered

 

[strider]

IANAL, but I believe that battery degradation that is markedly worse than standard profiles would, absent some proof of negligence to the battery, be covered under the warranty under normal interpretation of US law. The only way that a battery could degrade so much more quickly was because it was defective.

NO manufacturer warranties a specific battery capacity over time. There just isn't enough data and the variables are too many to do such a thing at this point. Remember people, warranties are to protect you against manufacturing defects, not deterioration due to use of the product. When your chainsaw or mower blade gets dull do you demand a new one under warranty? No. If the blade breaks while under normal use? Yes.

Second, we have experience with this via Roadster owners. The battery pack is divided into sheets and further into bricks of cells. The pack can only deliver as much as the weakest brick because when 1 brick hits its low limit the discharging must stop so as not to over-discharge that weak brick. So if 1 brick's capacity is dramatically less than the others your range will show lower. In this case Tesla will replace the battery as that brick is defective (with the Roadster you can see this when reading the log file - it will tell you which brick # is the weakest as well as how much capacity the weakest brick has and the average brick capacity. That weakest brick number will change every few days if everything is good. If it's the same brick number for a long time and there is a large difference between the weakest brick and average brick Tesla will replace the pack). However, if you range has dropped and all bricks have very similar capacity then they will not replace under warranty because the range drop has come from use of the battery and not a manufacturing defect.

There is a science to this and Tesla will take care of you if there's a problem with the battery. But as I tell people when they ask about my car, you should set aside some of the money from fuel savings as the battery is a consumable and will need to be replaced someday. I am confident I will save more in fuel costs than the battery will cost but this cost will come at some point.

 

[Yggdrasill]

NO manufacturer warranties a specific battery capacity over time.

Renault will give you a new battery if your battery drops below 75% capacity for the Zoe. It's a battery rental agreement, of course, but the principle is the same.

Tesla loads all the risk of battery degradation onto the customer. Renault takes all the risk onto themself. Why is that?

Does Renault have better batteries that they are sure will work as opposed to Tesla? If Tesla doesn't believe in their product, why should the customer?

There just isn't enough data and the variables are too many to do such a thing at this point. Remember people, warranties are to protect you against manufacturing defects, not deterioration due to use of the product. When your chainsaw or mower blade gets dull do you demand a new one under warranty? No. If the blade breaks while under normal use? Yes.

I certainly will demand a new blade if the blade costs $35,000 and dulled significantly faster than I could reasonably expect. (Of course, a dull blade is easily fixed by sharpening it. A degraded battery is garbage. So the situations aren't exactly analogous.)

Second, we have experience with this via Roadster owners. The battery pack is divided into sheets and further into bricks of cells. The pack can only deliver as much as the weakest brick because when 1 brick hits its low limit the discharging must stop so as not to over-discharge that weak brick. So if 1 brick's capacity is dramatically less than the others your range will show lower. In this case Tesla will replace the battery as that brick is defective (with the Roadster you can see this when reading the log file - it will tell you which brick # is the weakest as well as how much capacity the weakest brick has and the average brick capacity. That weakest brick number will change every few days if everything is good. If it's the same brick number for a long time and there is a large difference between the weakest brick and average brick Tesla will replace the pack). However, if you range has dropped and all bricks have very similar capacity then they will not replace under warranty because the range drop has come from use of the battery and not a manufacturing defect.

In other words, if all Model S batteries degrade to 70% in 4 years, you're out of luck. They all degraded at the same rate and consequently the degredation is normal and expected.

Look, I can understand that Tesla is hesitant to warranty a specific capacity, I really can. If I had my own company, I would be hesitant to bet the company on our products working as intended. Tesla would be bankrupt if all Model S batteries degraded faster than expected and needed to be replaced under warranty. If that were to happen, it would be better for Tesla to write off all their customers up to that point, and try to instead win new customers with improved warranties and promises. The way the warranty is worded allows Tesla to do that. If all Model S batteries are at 70% after 4 years, Tesla has the option of telling all Model S customers to get lost. It wouldn't exactly be good PR for the company, but at least they wouldn't be bankrupt.

Even so, they should bet the company on the Model S working as intended. It is the only right thing to do when your customers are betting up to $100k on the Model S working as intended. The customers shouldn't be stuck with all the risk.

 

[Yggdrasill]

I think this is the best answer. Because wear is highly dependent on usage, it becomes an issue how you should design that warranty. Should you warranty for the average case and take the risk of lots of costly warranty replacements (even for those only slightly worse than average)? Or should you warranty only for the worse case and then be disadvantaged in advertising (people would assume that is the average case, naysayers would assume best case).

There's also two types of wear: calendar wear (dependent on storage temperature and SOC) and cycle wear (dependent on discharge/charge rates, temperature, and SOC window).

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.

Right now electric car companies are at a disadvantage relative to fossil car manufacturers, because regular mainstream people who are considering buying a car will look at the battery warranties, see that there are no promises regarding durability, and think "I'll wait a few years until they are no longer experimental". Except Renault, who have done the sensible thing and put their money where their mouth is.

 

[Adm]

There is no such thing as a free lunch... With Renault you pay for the warrantee in the rental price. You pay $15000 for a battery of 22kWh over a period of 8 years and at the end you still don't own anything but a car* (* Batteries not included)
Now, should your 85kWh battery only have 50% left after 4 years and 50k mi without obvious abuse, do you really think Tesla would leave you hang out to dry? If that is the case I would strongly recommend you to cancel your reservation, because I would never do business with a company (or its technology) I don't trust.
Now, in case your battery would still have 70% left after 8 years it would be nearly as good as a 60kWh battery or at 50% as good as a 40kWh battery, in other words it has residual value (apart from scrap value)

 

[jkirkebo]

Second, we have experience with this via Roadster owners. The battery pack is divided into sheets and further into bricks of cells. The pack can only deliver as much as the weakest brick because when 1 brick hits its low limit the discharging must stop so as not to over-discharge that weak brick. So if 1 brick's capacity is dramatically less than the others your range will show lower. In this case Tesla will replace the battery as that brick is defective (with the Roadster you can see this when reading the log file - it will tell you which brick # is the weakest as well as how much capacity the weakest brick has and the average brick capacity. That weakest brick number will change every few days if everything is good. If it's the same brick number for a long time and there is a large difference between the weakest brick and average brick Tesla will replace the pack).

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 ?

 

[Johan]

Now, should your 85kWh battery only have 50% left after 4 years and 50k mi without obvious abuse, do you really think Tesla would leave you hang out to dry? If that is the case I would strongly recommend you to cancel your reservation, because I would never do business with a company (or its technology) I don't trust.

I agree, knowing what I know about Tesla I wouldn't worry. But the mainstream consumer has no knowledge of or relationship with Tesla. Nor the consumer media etc. They will be looking at the terms and conditions, believe me.

And as we can all agree Tesla's batteries will very likely hold up well and we can agree that Tesla will do right by their customers, why not put it into reassuring print?

 

[Yggdrasill]

There is no such thing as a free lunch... With Renault you pay for the warrantee in the rental price. You pay $15000 for a battery of 22kWh over a period of 8 years and at the end you still don't own anything but a car* (* Batteries not included)

You risk the exact same thing with the Model S. Owning a car with no battery.

Now, should your 85kWh battery only have 50% left after 4 years and 50k mi without obvious abuse, do you really think Tesla would leave you hang out to dry? If that is the case I would strongly recommend you to cancel your reservation, because I would never do business with a company (or its technology) I don't trust.

This isn't so much about what I think. I would fall into the category of an early adopter, so I will tend to put up with more inconvenience than most other people.

This is about what the mainstream consumer will think. And they aren't going to want to carry all the risk. Maybe Tesla will do okay when it comes to the model S and X without changing the warranties, but not when you get into the bluestar-territory... They will need better warranties.

Now, in case your battery would still have 70% left after 8 years it would be nearly as good as a 60kWh battery or at 50% as good as a 40kWh battery, in other words it has residual value (apart from scrap value)

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. The margins before a cell reverses is minimal, and cell by cell, the battery will die. There is of course some residual value, but nowhere near 50%. Maybe 5-10% + recyclable materials - recycling cost.

 

[Bearman]

The ZOE warranty is all well and good but do not forget the fine print, the price with the specific warranty is only for 6000 miles/year and 36 months.

 

[Yggdrasill]

The ZOE warranty is all well and good but do not forget the fine print, the price with the specific warranty is only for 6000 miles/year and 36 months.
View attachment 8471

Other distances/periods will be available, like with the Fluence. Link

And the £70 rental/month adds up to around $10,000, not $15,000. $15,000 is in all probability closer to the 8 year/100,000 miles cost.

 

[brianman]

You risk the exact same thing with the Model S. Owning a car with no battery.

Risking vs. gauranteeing...

 

[Yggdrasill]

Risking vs. gauranteeing...

You won't actually end up with no battery. The options are closer to being:

- Pay around $35,000 for a 300 mile battery for the model S, which might last 22 years/395,000 miles, but probably won't last much more than 15 years/200,000 miles, and could very well last a lot less than that.
- Pay around $35,000 for a 100 mile battery for a ZOE that is guaranteed to have a minium of 75% capacity for 22 years/395,000 miles. (Or pay less for less distance/fewer years.)

Tesla obviously has the advantage of the longer range, but when it comes to the warranty terms, Tesla is out-classed.

 

[Adm]

If you want to chose between a Zoë and a Model S, well they are both electric I guess.

In the Netherlands the battery of the Fluence cost €128 p.m. for 25k km's p.y. or about $150 and 15.6k mi. 22*12*150 = $39'600 for 343k mi
Assuming 5k km p.y. extra costs another €8 p.m. that makes $166 p.m. so 22*12*166 or $43824 for 412k mi.

Now you assume 395k mi in 22 years, so why wait until year 15? Why not swap after 11 years? Now in my turn to assume, I expect to be able to buy a new battery at that price. Now the choice is pay rent for a 100mi battery or buy a 300mi at the same price. I don´t have to think too long about that....