Battery warranty

Battery warranty

Any ideas how the battery warranty will work? Let's say that after 7 years and 70,000 miles the range of the car has decreased to 75% of its original 230 or 300 miles. Can I claim a new battery under warranty? What if the range had decreased to 50%? 20%? 5%?

What other symptoms would a battery exhibit that could lead to the need for replacement under warranty?

Volker.Berlin | 2012年5月30日

When I talked to a Tesla rep at the Geneva Motor Show in March, I asked the same question. Obviously, the fine print was not yet finished at the time, and the rep would not commit to any hard figures, but he stated that Tesla's warranty refers to a "practically-new" state of the battery. The warranty not only covers degradation in capacity, but also degradation in power delivery which becomes visible in higher 0-60 times.

In any case, the rep confirmed that 70% of the specified capacity cannot be considered "practically new" and would be covered under warranty.

ddruz | 2012年5月31日

When I was at the Menlo Park store last month I specifically asked about battery warranty. I was told it would not cover degradation at all. The battery would not be warrantied for 70% after 8 years or even X% after N years. I was told residual capacity was too dependent upon individual driving characteristics to warranty and that the battery warranty would cover power output but not residual capacity. I asked several times to be sure I heard correctly that percent of original capacity would not be covered and got the same answer each time. Hopefully the rep was misinformed but he was extremely knowledgeable in all other areas so one has to wonder if he was correct about this too. I hope he was mistaken. We will know soon enough.

mbergman | 2012年5月31日

I asked this question when I was at the NYC store for the technology tour a few months ago, and also of my Tesla rep via email, and got the same answer both times-

"The official warranty has not been published yet, but should be available soon. The battery warranty will cover parts and workmanship defects, but will not cover natural degradation over time."

Brian H | 2012年5月31日

I guess the question is "unnatural degradation", which presumably would trace back to parts and workmanship. Considering Tesla would have access to the log, it would be possible to establish whether unusual capacity drop was due to owner abuse!

gjunky | 2012年5月31日

Workmanship warranty on the battery is useless by itself unless it also includes a number for the residual charge. That residual charge number should be in the 80% or higher range in my opinion at the end of the warranty period.

EdG | 2012年5月31日

What do you think Tesla should say to someone who keeps their car fully charged - against Tesla recommendations - every day, thus reducing the capacity?

Peter Spirgel | 2012年5月31日


I thought Tesla wanted owners to charge the car every night? Wouldn't that keep the car fully charged every day?

EdG | 2012年5月31日

Tesla suggests you plug the car in every night. But you get to set how you want the car charged (at least this is the way it is reportedly done in the Roadster). If you want the full range for the next day, you put it in Range Mode which fully charges the battery at some cost to its lifespan. For everyday use you use a different mode which keeps the car at something more like an 80% charge maximum, thus lengthening the life of the battery pack.

Peter Spirgel | 2012年5月31日

@EdG Thanks for the explanation. I typically drive less than 20 miles a day during the week and slightly more on the weekends. I guess I won't be using Range Mode that often.

steven.maes | 2012年5月31日

@EdG. Thx for that info. I will have to do some re-calculation now since 80% may have some consequences. I drive +/- 160 km minimum a day at 120km/h (100 miles at 75m/h). No detour or going to the city for grosseries are included. Comes closer to empty than I thought ...

EdG | 2012年5月31日

Don't hold me to the 80% figure. All I know is that it's not 100%. And it may be different for the S than the Roadster.

For what it's worth, remember: the amount of savings you get for slowing down is dramatic.

Sudre_ | 2012年5月31日

I do not expect Tesla to warranty the charge capacity. That would be like warranting tire wear. I can take a year old tire out smoke the tires until all the rubber is gone and drive back in for new ones..... that doesn't fly. Likewise I can run my battery down to 2% every day and supercharge everyday. That will probably kill the battery in a few years..... not going to be covered under the warranty.
Now if you drive the car for 7 years normally and the battery has some low charge capacity, lower than other cars, then they will probably say it's a warranty issue after looking at the logs for the your car.

Brian H | 2012年5月31日

You could probably recharge nightly on a 110V circuit! Or a couple of times a week on a 220V.

"No detour or going to the city for grosseries" -- Jeez, sounds kind preverted! I doubt many people want grosseries in their Model Ses. They can be kinda gooey and gluey!

Will you be doing any shopping for groceries, tho'?

steven.maes | 2012年6月1日

@BrianH : thx for pointing that out.

If you try to spell my name correct, I will try to write my comments correct in this foreign language called English...

Brian H | 2012年6月1日

sorry 'bout that! There are a couple of stephens around, force of habit.

(I'd never seen "grosseries" before, and it was such a compelling image I couldn't resist.)

Volker.Berlin | 2012年6月1日

Brian H, if there's any typo which you can resist commenting on, as you seem to imply by your above post, please let me know which it is.

Brian H | 2012年6月1日


Brian H | 2012年6月1日

Lots of issues and stumbling blocks with a battery warranty, apparently. I can see why it's taking time to settle on a policy. Does anyone know what e.g. the Leaf battery coverage is? Or the Ford Focus EV?

Brian H | 2012年6月1日

And what is the wording of the Roadster battery policy?

gjunky | 2012年6月1日

I understand the issue with people abusing the battery in their Model S but if you follow regular charging procedures and the car only had 20% of it's original capacity left at the end (I am just trying to make a point with the 20% number), I want to make sure they will cover this under warranty. With making sure I mean in writing!

Volker.Berlin | 2012年6月1日

And what is the wording of the Roadster battery policy?

And... are there typos in there? :-P

Sudre_ | 2012年6月1日

That does make sense gjunky. It should stand to reason that a battery at 20% anytime over the warranty period should have some kind of manufactures defect in it if it was charged reasonably "normal". I would think they would replace it.

They may deduct for mileage.... kinda like tires tho... That's what I am waiting to read... or not. If you had the battery for half the warranty time they might only give you half the cost for a new battery.

Brian H | 2012年6月1日

Small things amuse ...

Yes, 20% left is almost unusable. That's also almost impossible under normal usage without a significant battery flaw. If the warranty covers anything, it would surely cover that.

Thumper | 2012年6月3日

My guess is that the warranty may take the form of replacing individual sheet or cells in the pack if they are found to be weak. This would be part of annual service and/or might be detectable by system monitoring and fixed as needed. Keeping the whole pack optimized should reduce the likelihood of major capacity loss at the end of 10 years. I hope!

Brian H | 2012年6月4日

Do you think the packs can be popped open like that? It would almost be a factory-level service job, I'd think.

Thumper | 2012年6月4日

I don't know. Just making it up as I go.

jerry3 | 2012年6月4日

Because the pack is supposed to be able to be replaced in somewhere between one and five minutes (depending on where you've read it) I would think it would be relatively simple (with the right equipment) to drop the pack, open the section with the weak sheet and replace it. This should be a far simpler job than in the Roadster.

Sudre_ | 2012年6月4日

It might be less labor to just replace the pack and send the bad one off to be refurbished. Pulling a battery pack out of a laptop is easy. Opening up that battery once it's out of the laptop is rather difficult.

Timo | 2012年6月4日

I agree with Sudre_ here. Replacing a faulty battery inside the battery pack can't possibly be a very fast job, there are electronics and cables to mess with and all of that in high-voltage environment. Also where there are one sheet of faulty batteries it is probable that there are others not yet giving out symptoms of failure. Much easier to just replace entire pack and send the faulty one to factory to be tested and repaired.

jerry3 | 2012年6月5日

You guys are probably right. I was thinking that the sheets just snapped in from the top similar to how a hard drive snaps into a Mac Pro.

jbunn | 2012年6月5日


Plus getting the seals right. Thing has to be watertight. Very watertight.

jerry3 | 2012年6月6日

Let's hope so. Today I was U-boat commander in the Prius.

Teoatawki | 2012年6月6日

There's no reason to assume you would get a new battery pack as a warranty replacement. I'm sure they'd provide a refurbished pack with a guarantee at least as long as the remainder of your original battery warranty.

gjunky | 2012年6月6日

Again: We need the details in writing.....

Timo | 2012年6月6日

jerry3 | June 7, 2012 new

Let's hope so. Today I was U-boat commander in the Prius.

Interesting. What happened? Initially and after.

jerry3 | 2012年6月7日

It rained really hard, water was up to and over the curb (so axle depth or a little higher) on the way home in several sections and visibility was down do about 50 feet during some portions of the 25 mile drive. All that happened was that the 74 mpg went down to 69. Also when I went to the covered ATM I got a face full of water so I really felt like I'd been standing on the conning tower during a tropical storm.

Timo | 2012年6月7日

Similar thing has happened to me twice. One time there was enough water that I feared that my car engine draws water in it, but that didn't happen: short thunderstorm with a lot of water coming down flooded the drains and water couldn't escape from road fast enough, so instead of driving in road I quite literally was suddenly driving in shallow river.

I have seen cars parked in places where water was over curb depth for hours. I hope that Model S battery pack can handle that, and if it doesn't warranty covers that.

Teoatawki | 2012年6月8日

@Timo: I have seen cars parked in places where water was over curb depth for hours. I hope that Model S battery pack can handle that, and if it doesn't warranty covers that.

 This is the purpose of comprehensive insurance, not the warranty.

Timo | 2012年6月8日

Not really. Insurance would be effective only if the car actually suffers something unexpected, warranty should/could cover the failure of surviving this kind of quite normal situation. It's rare, but not rare enough that it can be said to out of normal coverage of warranty. Just like it covers failed sheets of batteries inside of battery pack, it should cover failure of seals for protecting insides of battery pack in this situation.

That said it is possible that warranty doesn't cover any damage caused by snow, ice or water to the battery pack.

jerry3 | 2012年6月8日

I agree with Timo. It's not that rare either. Here in Texas it happens at least once a year and in a wet year it happens almost weekly during the spring. This should be something that any car is expected to withstand and if it doesn't it's warranty work.

bsimoes | 2012年6月10日

That amount of water might be considered flooding, and after Tropical Storm Irene and having my basement flooded, I know that State Farm Insurance does not cover any type of flooding. The Geothermal system is down there along with the backup furnace. I was not helped at all by the insurance company. I am curious to hear more about just how well sealed the batteries are, and what kind of testing has been performed in this regard. Water up to the wheel wells is up to the battery in an S I would suspect.

jerry3 | 2012年6月10日


Here in Texas there are no basements.

- Water up to the wheel wells is up to the battery in an S I would suspect

Correct. If you have the air suspension you can lift the body up which should help considerably. But my expectation is that the battery is very well sealed because even if you're not in a U-boat situation, road salt during the winter would severely compromise the battery--and road salt gets into everything.

bsimoes | 2012年6月10日

I had asked about the road salt/ road brine question when I called to make my reservation, and I was told that if anything the aluminum would react in a way that would actually make it stronger. I don't remember my chemistry, or what he said it would convert to...aluminum oxide? but this does have me concerned, especially if taking it through a car wash is discouraged. Again, I wonder if any tests have been run in this regard.

Brian H | 2012年6月10日

Aluminum oxide is a thin tough film that forms on exposed aluminum, and doesn't dissolve. If you scratch it, another thin tough film forms there. AFAIK, the only thing that compromises an aluminum surface is direct contact with certain other metals that messes up the electro-chemistry and causes progressive corrosion.

jerry3 | 2012年6月10日

I was thinking about salt getting inside the battery pack. The aluminium body won't care.

Sudre_ | 2012年6月10日

If anything gets into the sealed battery I would think you have a warranty claim.

What's with the discouraging car wash thing? I haven't read anything official yet that says you can't run the Model S thru a car wash. Some salesmen may say that because they think car washes damage the exterior of the car (and some do) but it has nothing to do with water getting in places it should unless you leave the windows open. If that is an issue Tesla is doomed.

I've also had so many people (not on here so much) quoting stuff about the Roadster as if it's about the Model S. They are two different cars.

Volker.Berlin | 2012年6月10日

Quick answer: for Roadster, we don't recommend carwashes at all. For Model S, the only "official" guideline so far is to avoid touchless car washes, which typically use some sort of acid to remove grime which could harm the paint and the finish. At this point, we are not 100% sure what our talking point is for carwashes, so for the moment I would recommend, if we had made any deliveries, that customers hand wash their cars whenever possible.
(Steve Davies, Tesla Motors EU Inside Sales Manager, by email May 30, 2012)

No mention of the battery pack.

GeorgeA | 2012年6月10日

If the included Telsa warranty does not cover a battery at "X" future years from now for whatever reason or if warranty period has expired, does anyone know how much it will cost to replace the various battery packs 40kWh 60kWh 85kWh in today's dollars?

Since current battery upgrade prices are 10K and 20K from the base model, does this mean a brand new replacement 40kWh battery would cost $5,000; 60kWh 10,000; and 85kWh $20,000? What is the realistic life expectancy of the battery?

Teoatawki | 2012年6月10日

We have heard from a Roadster owner who has put over 200K kilometers (~125K miles) on his car and the battery still has 70% of its original capacity. It seems reasonable to assume Tesla has learned a thing or three from their Roadster history to improve their battery tech. We can't really know, but Tesla wouldn't warranty for 8 years and 100K+ without an extremely high confidence level that the overwhelming majority of battery packs will exceed this mark.

In general the battery packs don't fail suddenly, they just gradually lose capacity over their lifetime. Your battery doesn't need replacing until the range no longer meets your needs.

On the replacement cost and capacity of the replacements in 10 years or so, my hope is that significantly lighter battery packs will have double the capacity and half the cost of today.

steven.maes | 2012年6月11日

Didn't Elon mention something about batteries in his last financial interview ? Something about 8-10 % increase in efficency per year ?