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Battery life

Battery life

I use my car a lot. About 30,000 miles per year. Can anyone tell me what the battery life expectancy is? If I have, say 100,000 miles on the battery, what kind of range will the battery have left? 90% of my travels are under 225 miles and that's why I ordered a S with the biggest battery. But, if the battery is rated at 265 miles and at 100,000 miles it only has, say 70% capacity left, that puts the range at about 185 miles. That just won't work for me. Also, does anyone know what Tesla's policy is on battery replacement. Will they replace the battery if it's under 80% capacity? 70%? 60%? or what? Thanks.

Neech | 15 January, 2013

Per the warranty - "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 New Vehicle Limited Warranty. See your owner documentation for important information on how to maximize the life and capacity of the Battery."

Sounds like Tesla is off the hook even if your battery is at 70% capacity in 4 years instead of 8, Tesla would not cover it under warranty. Brian H. makes a good point about what is normal and what is a defect. Severe loss of battery capacity (outside the "norm") should be considered a defect.

drp | 15 January, 2013

I had some questions for Tesla about battery life and cold weather operation as well as regarding my car sitting outside during the day, while at the office. Here is the official response:

I wanted to send you an email that we have received from HQ regarding your question about the loss of range when the car is parked outside during the cold weather.

Model S does not irreversibly lose energy when it’s cold outside.

In cold conditions, the accessible battery energy is correspondingly low, resulting in an underestimated range number. However, the liquid thermal control system immediately starts warming every cell in the battery, so accessible energy grows exponentially as the battery reaches nominal temperature.

This is evident by looking at the battery graph, which approximates battery state of charge. After a standard mode charge in both warm and cool temperatures, the customer will notice the battery graph looks identical (e.g. approximately 90% full).

A future software update will better estimate range based on where the battery will be after it heats up, whereas current firmware calculates range based on current temperature.

Cars left in cold ambient temperatures do not inherently lose range. Reduced range predictions shown on the instrument panel and touchscreen reflect range assuming the battery will remain at cold ambient temperatures. As the car is driven or preconditioned, battery temperature rises and driving range is more accurately predicted. As always, Model S should be plugged in when not in use, especially in cold weather.

I hope that your question was addressed appropriately, please feel free to add feedback should you have any more questions.

Best Regards,

That's the end

Superliner | 15 January, 2013

It should be noted that while plugged in the Battery Heating / Cooling system/s will attempt to keep pack temps nominal and seemingly leaving the car plugged in whenever possible may be the best bet for longevity by minimizing temperature extremes. I would assume that Tesla has matched the charging algorithms of their charger/s to the specific needs of the pack. Might be why the charger is on board the car?? They surely would not include an on board charger that would charge the pack in a manner that would damage it.

I plan on following the owners manual / charging instructions and will plug my model s in whenever possible and for sure every night when I return home no matter how much or little distance I travel during the day.

drp | 15 January, 2013

Superliner

I too will follow the Manual and keep it plugged in when possible in the cold, even if its a 110v.

Brian H | 15 January, 2013

Probably people in cool climates will get greater lifetime range. One dude in Alaska has lost 2% in 3+ yrs. and 40K miles on his Roadster, and TM claims major improvements in battery quality and management since the Roadster.

drp | 15 January, 2013

I will pass 100000 miles at about 3.25 years so I will keep you posted from the Chicago area

drp | 16 January, 2013

Hum

Amped | 16 January, 2013

This page states 1.66% loss yearly
So a 60kwh will go from 200 to 168 range after 9 1/2 years at 65mph, with ideal driving conditions.
http://images.thetruthaboutcars.com/2012/08/Model-S-range-Tables.pdf

Robert22 | 16 January, 2013

Even if not plugged in at night, the pack will continue to normalize temperature extremes
protecting itself, albeit at the expense of range. Unless you need the range, no need to plug in all night per delivery specialist. My concept of the car sipping small amounts of juice all night to protect itself is apparently incorrect.

Brian H | 17 January, 2013

Robert22;
you can "force" that by restricting the amperage, or using a 120V (few miles added, but keeps the battery warm and ready to go, with regen). As long as you don't fill it before leaving.

wonder | 31 January, 2013

National Renewable Energy Labratory (NREL)
Came across this study by IEEE today.
Thought this thread might find it interesting so dug it back up
Title: Design of Electric Drive Vehicle Batteries for Long Life and Low Cost

Various Lithium Ion Chemistry includes Model S - Li(Ni,Co,Al)O2 Cycle Life Goal 3,000 - 5,000
Impact of different Battery Cooling Systems.
Impact of Cycle Depth of Discharge (DoD) on Battery Life
Impact of Regional Temperature on Battery Life
Cathode/Anode aging - deterioration

End-of-Life approaching 10,000 cycles at 1 cycle/day
Where End-of-life is defined when
ΔDoD * (actual capacity) > available capacity

http://www.nrel.gov/docs/fy11osti/48933.pdf

Need to look it over more carefully and give some thought
but thought would post here.

:-), my wife the teacher corrects my spelling too

wonder | 31 January, 2013

If I interpret correctly chart on Page 21 of NREL pdf
indicates might expect 80% of "Relative Capacity" for as many as 4,000 cycles.

If you figure 1 cycle/day that would mean you might expect 80% of Battery Capacity for nearly 11 years.

wonder | 31 January, 2013

Here is another PDF that this thread may find interesting by US Department of Energy National Renewable Energy Labratory (NREL) which may show a statistical mean probability of having 80% of Capacity in year 8 of Battery service life based upon Fleet Studies of PHEV batteries with similar chemistry.

http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/53470.pdf

wonder | 31 January, 2013

Listing of other NREL papers that might be interesting to some
http://www.nrel.gov/vehiclesandfuels/energystorage/publications.html#fact

Brian H | 31 January, 2013

wonder;
1 cycle/day is about the max I can imagine really using the car. >200 miles/day? That's your whole life spent driving! Most people would use no more than ¼ that, I bet.

Go_Peddle_4_me | 1 February, 2013

@Wonder

Someone earlier in this post mis-read the specs data and thought the battery life dropped by 70% after 3,000 cycles. The specs say there should be no less than 70% capacity left after 3,000 cycles. So, this means after 8 years the 85 kWh version should still get at least 171 miles per charge based on the EPA 245 m/charge rating. If it only drops to 80% capacity then expect to get 196+ miles per charge still.

For people who only drive say 40-50 miles a day and charge every night (1 cycle), the battery is essentially just topping off every night. Li-ion batteries charge to about 85% capacity fairly fast and then using a lower current "bounce" the capacity higher until 100% charge is achieved. Li-ion batteries do best and last longer when constantly trickle charged. That's why TM suggests leaving the car plugged in when not using it. It maintains the battery life longer besides the constant falloff from non-use.

I would hazard to guess that the people who only drive 40-50 miles a day could see the batteries last 10-12 years or more.

Brian H | 1 February, 2013

Yes, insider scuttlebutt has it that engineers actually are expecting 16-20 yrs in moderate use. That famous "safety margin" again.

Brian H | 1 February, 2013

BTW, TM will not replace the battery due to capacity reduction unless it is due to a manufacturing flaw. I would expect verry, very few warranty replacements.

L8MDL | 1 February, 2013

BH - verry ? Very funny!

wonder | 5 February, 2013

Yes, I agree that if you are not depleting the battery daily you might see good range (what ever that is) for 12 - 13 years. That seems to be suppoorted by general information I've read on the Lithium Ion battery. That fact and the impact of cold weather on range is one reason to buy more battery than you require. I noted in Wikipedia it states that Tesla Motors will "pay" $1,000 for every year you keep the battery past 8 years. Think that may be true only if you have the battery replacement option. I called Tesla and configuration guy left phone and asked for confirmation. Came back and said yes that's true for up to two years but qualified the statement saying that probably would not be cash but some form of service ..., my thoughts are maybe annual service or three. I think my goal is to shoot for 11 - 13 years unless range becomes unworkable. Guess will find out in March or April of 2024 :-)! Think this thread will be tired by then :-).

wonder | 5 February, 2013

Nice to hear ...,

Yes, insider scuttlebutt has it that engineers actually are expecting 16-20 yrs in moderate use. That famous "safety margin" again.

and hoping its true!!

Would be nice to see the car achieve 200,000 plus miles on first battery and to retain excellent condition. Swap in your next battery pack (maybe with enhanced range due to weight or chemistry differences) and run another 200,000 plus miles all while retaining excellent condition.

vgrinshpun | 24 February, 2013

johnchamplinhal - Would you be able to share all assumptions that you've made for the model S Battery modeling that was mentioned in your Jan 11 post?

There is a lot of activity here and elsewhere on various financial internet sites with many constructing cost of ownership models which almost universally assume that Model s battery will have to be replaced at least once in the lifetime of the car.

I, however, intuitively feel that Model S battery, especially 85kWh, will last the lifetime of the car under all except the most extreme conditions and would be very interested to see detailed information on your assumptions and inputs for this modeling

Thanks!

My5bAby | 24 February, 2013

I have driven 10,700 miles. I've ranged charged only twice (shortly after delivery) & have not let the charge drop below 15 miles remaining. So far there has been NO sign of degradation what so ever. Frankly I'm no longer worrying about it. I drive 100 miles 5 days a week for work. I've taken weekend trips every weekend ( I really LOVE DRIVING THIS CAR) that are at least 300 miles round trip. Over the past 3 weeks I've also been using the superchargers. I don't know how TESLA has done it but this battery continues to perform.

vgrinshpun | 24 February, 2013

My5bAby - what is the overall percentage of time that you keep your MS plugged in and in what were the temperatures the car was exposed to over it's lifetime?

Thanks!

Brian H | 25 February, 2013

0% for 1 yr X 10 yrs = 0%!

Good deal.

m.steinbuch | 12 July, 2015
georgehawley.fl.us | 12 July, 2015

Interesting and worthwhile data that supports the notion that the Panasonic 18650 cells used by Tesla age very gracefully. One question: battery researchers typically measure battery life against the number of charge-discharge cycles. Do you have anything like that?

rxlawdude | 12 July, 2015

@George: There is a capacity vs cycle graph among the others.

TeoTeslaFan | 12 July, 2015

Hi m.steinbuch,

This is Teo. Thanks a lot for your article. I created the charts in the Merijn survey. In the article you said "replaced batterie cases are left out because their mileage is not known". This is not correct. All replacement batteries are included and their mileage is calculated accurately.

Not only is their mileage on this owners car considered but the mileage on the previous car is also calculated and added because most replacements are refurbished. All this is explained in great detail at the bottom of the charts page.

If the replacement battery had 10,000 miles before it was installed to your car and you added another 20,000 miles, the chart will show 30,000 miles for this battery. The chart reflects the battery accurately.

I recently added a stats page where you can find interesting data. To make these stats more accurate, a lot of things is going on in the background. For example only the last entry from each user counts.

georgehawley,
There is a cycle charts on the charts page. In the article click the "google doc file" link.

jordanrichard | 12 July, 2015

Teo, if that articles conclusions are correct, one will never have to replace their battery pack.

Please correct me if I am wrong here.
Generally speaking it takes 50,000 miles to "lose" 6% (16 miles) Then beyond that it tappers off to 1% for every 30,000 miles? If this is true, I calculated that by the time one can't travel 150 miles (typical distance between chargers) one would have driven 1,250,000 miles.

I will add that I have contributed to your spreadsheet and per that sheet, after nearly 30,000 miles, I still have no range lost.

sorka95032 | 12 July, 2015

Everyone should watch this video:

https://youtu.be/9qi03QawZEk

Notice the section where he talks about tapering off in terms of loss of capacity but at some point catastrophic and sudden failure occurs due to electrolyte oxidation blocking off the pores on the negative electrode. It's not the thing that causes slow degradation but the thing that suddenly kills the cell.

KidDoc | 13 July, 2015

I'm at almost 30,000 miles and my full charge on an s85 varies from 261-267. I would estimate <1% loss if even that.

Captain_Zap | 13 July, 2015

@sorka

With over 7000 cells, I'm not worried too much.

m.steinbuch | 13 July, 2015

ha! If all cells loose 10% the whole car looses 10%, but i agree, the data shows it is looking quite OK!

teslamonterey | 13 July, 2015

I appreciate the YouTube video. I don't appreciate the hour of B.S. paid for by a Tesła consultant. Had he wrapped up the hour presentation with solid recommendactions on all of his data to help us properly charge our batteries it would have been worth every minute. He seems to state fast charging and high temperatures are not a good thing. Should we stay away from all Super Chargers and charge from a 110 wall unit at home? Idiot!

jordanrichard | 13 July, 2015

Big, if the batteries get too warm, the cooling fans kick in to cool the pack down. It is cars like the Leaf that don't have a temperature management system that will have relative short lives. Unless studies are done on batteries that have the same chemical composition as Tesla's batteries, we won't know how well our packs will hold up in the real long run. So far real world accounts show that these packs won't need replacing anytime soon. I am in the same situation as KidDoc. I am at 29,903 miles and couple hundred ago I tried charging until she would stop, but I ran out of time. The car indicated 100%, 261 rated miles, yet she was still charging. So I really don't know what my full range number is. Even if she did stop at 261, that is only a 1.5% loss after nearly 30,000. Now of course we can only hope this rate stays linear.

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