Battery warranty and range

[pbleic]

For the 8 year battery warranty - is it only for complete failure? How about loss of range?

Nobody would expect a new battery if they lost 10% of range at 40,000 miles. But how about 25%? 50%? 75%? 90%. Where, if anywhere, would Tesla replace a battery that was excessively losing range?

Trying to understand things during the long wait.

 

[bhuwan]

I thought they guaranteed 70% or higher after 8years

 

[mknox]

My understanding is that the battery warranty covers complete failures and "excessive" loss of range. bhuwan suggests 70% after 8 years, but I don't think I've actually heard a firm number from Tesla directly, and don't see anything in the warranty language that talks about a firm number.

 

[mkuendig]

My understanding is that the battery warranty covers complete failures and "excessive" loss of range. bhuwan suggests 70% after 8 years, but I don't think I've actually heard a firm number from Tesla directly, and don't see anything in the warranty language that talks about a firm number.

i got told from a tesla sales rep that 3% per year is an acceptable loss. according to excel that is 78.37% of original capacity at year 8.

what do people see at 12 and 18 months ownership ? or 10k, 20k , 30k miles ?

 

[apacheguy]

i got told from a tesla sales rep that 3% per year is an acceptable loss. according to excel that is 78.37% of original capacity at year 8.

Oh good. Based on those numbers I qualify for a pack replacement since my rated miles decrease by more than 7% per year.

 

[FlasherZ]

i got told from a tesla sales rep that 3% per year is an acceptable loss. according to excel that is 78.37% of original capacity at year 8.

what do people see at 12 and 18 months ownership ? or 10k, 20k , 30k miles ?

This will get complicated, because the mileage you're seeing is a result of a bunch of factors, one of them being pack balance.

I have 19,500 miles on my car, 15 months of service, and it will charge to 257 miles - after rebalancing the pack. It was 252 before balancing. That's a 3.018% loss over 15 months.

Tesla has left the replacement guidelines vague, but it has less to do with miles and more to do with when they detect failed strings of cells in the battery.

There are entire threads by some of the battery experts here devoted to that conversation, with lively argument, I won't requote them here but it's pretty in-depth reading for a long time.

 

[mknox]

what do people see at 12 and 18 months ownership ? or 10k, 20k , 30k miles ?

My car has about 20,200 miles on it and is just about 1 year old. The most I can get is 245 miles on a full (100%) charge. When it was a couple of months old, it got up to 260 miles while doing a Range Charge, but I had to unplug and leave before it completed. If I assume 265 when new and 245 now, that's about an 8% reduction.

I'm given to understand that the degradation is steep at first, then levels out somewhat.

 

[deonb]

I'm given to understand that the degradation is steep at first, then levels out somewhat.

Yip, my car charged to 265 when it was new, and then dropped to 255 within 3 months. It stayed at 255 for around 9 months, until I did a pack balance over the weekend, and now it's at 258.

13'000 miles. B pack.

 

[rdrcrmatt]

B pack.

How can you tell which pack you have? my vin is P11605


How do you do a balance?


I'm almost to 20,000. I haven't range charged in a while.. or balance I guess. I'll do it some time soon to see where I'm at.

 

[stopcrazypp]

My understanding is that the battery warranty covers complete failures and "excessive" loss of range. bhuwan suggests 70% after 8 years, but I don't think I've actually heard a firm number from Tesla directly, and don't see anything in the warranty language that talks about a firm number.

Do you or anyone else have an updated copy of the warranty? The most recent I can find is here:
http://www.teslamotors.com/forum/forums/battery-warranty-model-s

But it still has this part:

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 under this Battery Limited Warranty. See your owner documentation for important information on how to maximize the life and capacity of the Battery.

The language was extended to cover "malfunctions" also after the fires (previously it only covered "defects"), but it still seems to not cover degradation (as before). There seems to be no mention of "excessive" degradation.

 

[AmpedRealtor]

Officially from the warranty:

"... Loss of Battery energy or power over time or due to or resulting from Battery usage, is NOT covered under this Battery Limited Warranty."

All statements regarding what percentage of degradation is or isn't acceptable are coming from owners, not from Tesla. Tesla has made no statements, public or in writing, regarding what amount of degradation, if any, would lead to a pack replacement other than what is stated in the warranty (degradation not covered). So far, the only packs that have been reported replaced in these forums have been due to outright failures. I do not recall a single incident of a pack being replaced due to excessive degradation.

Unless you have an email from a Tesla representative stating that the battery would be replaced due to severe degradation, I would not rely on statements made by owners. Per the warranty, if you're left with 50% usable battery in two years, you are not entitled to a new battery under the warranty. While that example is admittedly extreme, it illustrates the warranty exclusion.

 

[stopcrazypp]

Unless you can prove the degradation is a result of a defect, it's unlikely Tesla will replace your pack given the way the warranty is written. An example from the Roadster is a "sheet" of the battery (analogous to a module in the Model S) being much lower capacity than other "sheets" in the battery. That was enough for Tesla to do a replacement of the sheet. The problem with the Model S is the battery information available to the user is much less than for the Roadster.

 

[bhuwan]

Good find. I kind of feel scammed, all employees have always said don't worry about the battery. Sad to see degradation (even unusually high) is not covered. Oh we'll.

 

[ecarfan]

Good find. I kind of feel scammed, all employees have always said don't worry about the battery. Sad to see degradation (even unusually high) is not covered. Oh we'll.

As Ampedrealtor has clearly, and I think accurately, pointed out, Tesla has never stated how much battery degradation is enough to trigger a replacement under warranty. Which I think is reasonable on their part and no different from other consumer electronic manufacturers who make products with lithium ion batteries. There are so many variables involved that it would be foolish for Tesla to give a specific number for "allowable" battery degradation given that the basic chemistry tells us that some degree of degradation will take place in every battery Tesla installs in their cars.

The experience of Roadster owners who have put many tens of thousands of miles on their cars and what happens to their batteries has been well documented (can someone provide a link to that paper? I don't have it on my iPad). Some battery loss always occurs over time. It is related to miles traveled. It is not directly related to number of charge cycles or average SOC, if I remember correctly.

Obsessing over a couple of miles change in max charge range is over thinking the situation.

 

[glhs272]

How can you tell which pack you have? my vin is P11605


How do you do a balance?


I'm almost to 20,000. I haven't range charged in a while.. or balance I guess. I'll do it some time soon to see where I'm at.

The version of pack you have is listed on the label attached to the battery. This label is located on the side of the battery near the front passenger side wheel well.

On another subject:
To those complaining about loss of range, do at least 3 real battery balancing sessions and see where you are really at.

 

[stopcrazypp]

Good find. I kind of feel scammed, all employees have always said don't worry about the battery. Sad to see degradation (even unusually high) is not covered. Oh we'll.

In general, the degradation on Tesla packs have been much better than other manufacturers (even worse case vs typical case for something like the Leaf for example), so it's reasonable to say not to worry about it. The problem with saying something like "unusually high" is that it's too vague. What you can be assured of is degradation from defects would be covered and that's typically the cause of "unusually high" degradation (the symptom would be certain modules degrade much faster than other ones). The only exception might be if all your modules were defective and yet still degraded at the same rate (highly unlikely).

The only car I'm aware of (besides from those with leased batteries) with a very explicit degradation warranty is the Leaf. But that's because Nissan had a lawsuit, and the warranty isn't that good either (5 years / 60k miles for 30% degradation).