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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.

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

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.

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

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

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.

@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.

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

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.

BH - verry ? Very funny!

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 :-).

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.

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!

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.

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!

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

Good deal.


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