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.

ChasF | December 28, 2012

The following thread over at TMC has a lot of related discussion:

Brian H | December 28, 2012

Seems like the replacement policy might work for you. Warranty would only cover flaws, not normal degradation.

As a side note, the "safety margin" TM appears to have allowed itself is about 100%, which is to say the stated decline rate is about double what they actually expect (and have considerable Roadster experience to draw on).

DouglasR | December 28, 2012

On the other hand, if you are routinely charging to a range of 265 miles (rated), your battery will degrade faster. TM recommends that you use a "standard" charge rather than a "range" charge on a regular basis. A standard charge will give you 230-240 rated miles.

wrcrusaders | December 30, 2012

Thanks all. But, an 8 year replacement battery option still puts me at 240,000 +/- miles. I still don't know what kind of range or battery capacity I will have at 240K....or 100k...etc.

paulehardy | December 30, 2012

I read somewhere that charging the battery quickly shortens battery life. Does anybody know if this is true? If so, would it be advisable to avoid the high powered wall connector (and twin chargers) if I don't need them? Would just sticking with a 240 volt outlet in my garage be a way of maximizing battery life if I don't think I need the quicker charges?

jat | December 30, 2012

@paulehardy - Nissan says fast-charging the LEAF once per day (close to the charge rate of the Supercharger) won't degrade the battery, but they don't recommend more than that. I believe Tesla has said that charging via the HPWC doesn't impact the battery longevity -- for the Superchargers, there have been conflicting reports, but I believe you can charge as often as you want at those and it just slows down charging over 50% to protect the battery. I think the bigger issue is repeatedly charging to 100% (max range mode).

I'm getting dual chargers and the HPWC even though I plan to normally charge at 50A (so I can also charge the LEAF at the same time) -- that way I will have the option to charge at 80A if I need to.

Sudre_ | December 30, 2012

If I recall correctly at the supercharger opening ceremony Elon said the Superchargers will not damage the battery.

BigTex | December 30, 2012

Spoke to a Tesla rep today who said Supercharging is harder on the battery than normal charging and would only recommend it for road trips as opposed to an all-the-time thing.

drp | December 31, 2012


I'm happy to see your post. Sound very similar to my life, driving about 650 weekly...165 daily on some 3-4 days each. I worry a little but suspect there should be no issue even with degradation but I am concerned about winters in Illinois and the day-drain. I am working on convincing e building to contact Chargepoint to set something up but I don't know how much charge we get from a J-1772 either. It's all new to me.

I hope e "300" or "EPA 265" range is real and We don't have to worry, ever.


nickjhowe | January 5, 2013

@drpeggau - I just posted this elsewhere but thought it useful to post here - I just did the first freeway run in my performance S and averaged 360-370 Wh/m with cruise control at 80mph with A/C on and two people in the car on a flat (South Florida) I-95. That equates to c.225 miles with a Range charge. Better than I expected.

My5bAby | January 6, 2013


I suggest you consider Cliipper Creek instead of Charge point. charge point is 30amps max (roughly 20 mph charging). Not very useful for a Tesla.


drp | January 6, 2013

I had a very long conversation with a manager at the Tesla store in Oak Brook Illinois yesterday. He indicated that the battery likes to be charged at a slower rate rather than a faster rate in terms of limiting degradation. He said that I really would not need a home charger or HPWC but would be best off using the NEMA 14 – 50. Most of the time the car would have at least eight or nine hours to charge anyway. He suggested driving the vehicle in range mode with the displays set off And this would limit the drain on the battery while it is parked. He indicated using units/format "rated" which monitors how I'm driving. He also indicated that I would probably have to charge to max range most of the time.

tsx_5 | January 11, 2013


I as I am waiting for my opportunity to acquire said vehicle - I find reading about everyone's experiences to be really helpful (if not a little concerning).

Based on what I've seen here, people are getting about 70-75% of the rated miles. Given that Tesla states that after 7 years battery capacity will have dropped by 70%, your range will be significantly curtailed.

I am really looking at this, as my daily commute is about 135 miles per day. With the above info, at about 6 years I no longer will be able to make it back and forth to work...

The replacement plan only kicks in after the 8th year - suggesting that there would be 2 years that I couldn't use my car (and at this price, that would be totally unacceptable).

Am I off base here? Did I screw up the math? Leasing would be an unlikely option as I drive too much. And I would take at least that long to pay it off..

wonder | January 11, 2013

Have been looking into range impacts due to cold weather and battery age on Tesla Model S. Trying to decide if I need to step up one battery level to support year round driving and driving as battery ages. Information I've seen indicates I should allow for a 20% range impact as result of cold weather (though suppose for extreme cold might be worse). With Volt and Leaf apparently range impact as result of cold can be 40%. Also concerned with impact to range resulting when car is parked at work location for 8 hours in cold.

Not enough of an engineer to know how Direct Current Internal Resistance (DC-IR) and capacity might together impact range (effective capacity) but with my limited engineering skills this article leads me to believe that under "normal" weather conditions one might expect battery capacity to be 90-100% of original capacity after 8 years of service.

Believe the article studies the individual Panasonic Cell that Tesla integrates into the Model S battery pack.

drp | January 11, 2013

100 200 300 Storage periode /days
Fig.1 Storage characteristics of tested cells. Closed and open symbols indicate stored SOC of 90 and 30%, respectively. Circles and triangles indicate stored temperatures of 25 and 60°C, respectively. The vertical axis indicates the change ratio in discharge capacity or DC-IR with respect to the initial value.
Fig.2 Charge/discharge cycle characteristics of tested cells. Cycle tests were performed in voltage range of 3.60 to 4.05V. Closed and open symbols indicate operated current rates of 2 and 1It, respectively. Circles and triangles indicate ambient temperatures of 25 and 50 °C , respectively. The vertical axis indicates the change ratio in discharge capacity or DC-IR with respect to the initial value.
1000 2000 3000 Cycle number /-
● SOC90% 25°C ▲ SOC90% 60°C ○ SOC30% 25°C △ SOC30% 60°C
●2It 25°C ▲2It 50°C ○1It 25°C △1It 50°C

Development of High power and Long life Lithium secondary batteries
Shoichiro Watanabe, Takashi Hosokawa,
Ken’ichi Morigaki, Kensuke Nakura and Munehisa Ikoma
Panasonic Corporation, Energy Company Technology Development Center
1-1 Matsushita-cho, Moriguchi City, Osaka 570-8511, Japan

drp | January 11, 2013

The chart supported no more than 20% loss. Hard to believe

wonder | January 11, 2013

Anyone with current and applicable engineering and or science skills care to interpret the paper? Looks like 90% to me 3000 cycles working out to about 8.5 years if you figure one cycle per day.

wonder | January 11, 2013

drp you see "no more than" 20% ..., we were posting at same time!

wonder | January 11, 2013

Ahh I see your 20% if you figure extreme heat conditions.
I'm not going to see that kind of heat!

wonder | January 11, 2013

I've seen information that leads one to believe that, with respect to battery life, Lithium-Ion "likes" being stored in cold ..., in that it can/will extend battery life. Suppose that may be why study covered the temp range it did ..., might be more problematic for battery cell.
25C <=> 77F
50C <=> 122F

DouglasR | January 11, 2013


With careful driving, you can get pretty close to rated range. Very cold weather, hills, heavy use of accessories, and most of all, speed will reduce that range considerably. However, I think you will be able to get 135 miles on an 85 kWh battery for a long time, certainly eight years. Besides, isn't it likely that in a few years there will be places to charge up at work and along your route?

tsx_5 | January 11, 2013


I'll admit it, I'm like Sammy Haggar... I can't drive 55 :}

Where I live it's not to bad on the hills and while we have 4 seasons, it's not really been that harsh (nothing like the UP in Michigan).

There is a snow-ball chance in hell that charging stations will be placed near where I work. We are (and have for years) had significant issues with managing power and cooling requirements -- and that isn't going to change soon.

I hope you are right... I generally keep cars for a long time (my last two 10, 9+ years) and I NEVER have any considered spending this much for a car. So, I would like to have it for longer than it would take to payoff.

johnchamplinhall1 | January 11, 2013

wonder and drp:

Be a little careful about the date in the ECS abstract. I am not sure the Panasonic cell that they tested had the same positive electrode composition as the cell used in the Model S. There is a good possibility that the Model S positive electrode contains a good percentage of manganese. I am extremely familiar with the chemistry of the cell studied. The variations in its performance are driver by the positive electrode, hence the concern with using these data to access the Model S battery.

The data do, however, give a very good feel for how you should tread your battery; ventilate the garage and delay recharge as long as possible (this should become easy once the new new software version is released.

By the way, cells tested and the Model S cell do behave similarly. About five years ago I developed a heuristic model for the tested chemistry. I have applied this program to my Model S and example of its prediction with a 60 mile daily round trip is a life greater than 20 years.

Brant | January 11, 2013

"delay recharge as long as possible.."
What do you mean by this? Let the battery get low before recharging?
Tesla states "The Tesla battery is optimized for nightly charging: topping off frequently enhances the longevity of your battery."

drp | January 11, 2013


I drive @ 165 miles daily 3-4 days a week and it will sit for 6-7 hours. What does the heuristic model suggest I do to make the battery last a meer 10 years for such a daily commute, expressway, 65 mph with normal interior climate and a radio on? Any suggestions or insights would be tremendously appreciated.

jat | January 11, 2013

I have found the heater makes a huge difference -- I got my car on Sunday, and early in the week it was around 40 degF. I was getting about 380 Wh/mi, which was a lot higher than I expected. The last couple of days have been in the 60s, and I have actually been averaging around 320 Wh/mi (and for non-highway sections, getting well above the rated miles calculation).

July10Models | January 11, 2013

I think he means to have the car finish its charge cycle when you are ready to use it. You don't want to get home from work plug the car into the HPWC and fully charge the car in four hours just to have it sit there overnight. The battery is not very comfortable at full charge but, full charge is just what you need before setting out. What ever you plug the car into, you should limit the charging current so that the car will be ready just when you need it.

Brant | January 12, 2013

From the owners manual:

Your Model S Battery is one of the most sophisticated battery systems
in the world. The most important way to preserve the Battery is to LEAVE YOUR MODEL S PLUGGED IN when you’re not using it. This
is particularly important if you are not planning to drive your Model S for several weeks. When plugged in, the Model S wakes up when needed to automatically maintain a charge level that maximizes the lifetime of the Battery.

Brian H | January 13, 2013

A cycle refers to a full charge from empty; two 50% charges are just one cycle. One cycle a day seems like a lot; pushing the car to its limits every day from day one.

Fredhmartin | January 13, 2013


Yep, I agree completely with your view above. I'm expecting delivery in March/April (60 kwh, Air). #9965

I'll only rarely do "range" charges, but when I do, I'll immediately start driving in order to drastically limit the amount of time my battery is ever at 100% charge. Likewise, I'll hardly ever run my battery down to nearly empty and I'll begin charging ASAP.

My normal nightly plan during the work week is begin charging after midnight and have the standard charging finish right before I leave for my morning commute. I only have a 30 mi round trip so many days I can probably start charging around 5am. I'm also considering not charging at all some days. I'd like to see more analysis on the lifespan benefits of having the battery below an 85% SOC most of the time.

Robert22 | January 13, 2013

Since I have a short commute (15 miles round trip) I asked specifically about the need to "leave the car plugged in so it could *wake up* and draw automatically when needed" as was mentioned above. My plan for regular commuting is to charge at work a few times a week to keep the rated range between 190 and 237 (my full standard charge). I was told by a delivery specialist the recommendation in the manual was geared to those that might leave the car for prolonged periods of inactivity at an airport, etc. I was told there would be no adverse effect on longevity to charge sporadically in this fashion, but I've received conflicting information from the ownership experience team.

I think this issue needs to be clarified by Tesla because these batteries have clearly been engineered for special functionality not found in routine lithium cells. If there are nuances to maximizing longevity given the unique nature of the batteries, they need to be explained more fully to owners.

johnchamplinhall1 | January 14, 2013


Batteries wear out because of stress which in turn are caused by factors such as voltage, temperature and degree of use. 165 miles a day (5 days a week?) is a lot. I would expect conservatively a life of 10 years or more to 70% of initial range (70% X 240 miles 168 miles) in may temperature Southern California marine environment.

johnchamplinhall1 | January 14, 2013


What I meant was to reach full range say an hour before leave on a regular commute. Higher voltage storage is harder on a battery the lower voltage

Brant | January 14, 2013


bbmertz | January 14, 2013

I've heard conflicting views on this battery charging issue as well. My original understanding was that it's best to charge the car whenever it's not in use and that range-charging as well as draining the battery close to zero would reduce battery life. However, last week I heard from a service advisor that it's a good idea to let the battery drain down and range charge 2-4 times per month to ensure that all of the cells are getting even use. Which approach is best?

wonder | January 14, 2013

battery cycle life – The number of cycles, to a specified depth of discharge, that a cell or battery can undergo before failing to meet its specified capacity or efficiency performance criteria.

So not so clear as "full discharge" or "deep" discharge required for "cycle". Believe to some degree depends on battery in question. For example its my understanding that Chevy Volt will maintain 30% State Of Charge (SOC) to improve battery life. In other words 30% of battery capacity is held in reserve and operator does not have access.

As stated in my earlier posting I am not sure the Panasonic Study I posted referred to cell Tesla uses but information I came across from various sources seemed to support that it does. I saw no source that supported the Tesla battery having Manganese (MN) in its composition. They also refer to the Tesla battery as (NCA) if I recall correctly which believe points to Nickle, Cadmium, and Aluminum (no manganese). That said I am not Tesla Engineer so can't say conclusively and have to rely on information from internet.

1)Research I've done with respect to Lithium-Ion indicates that you can extend the life of battery if you do not fully deplete the battery. So one way to extend battery would be to purchase Tesla Battery Pack with more capacity than you would day to day typically. In other words maintain a higher nominal daily State Of Charge (SOC).

2) Research also points to extending Lithium-Ion Battery Life by not "over charging" cell (dramatically shortens life) and further benefit is had by not fully charging battery cell. Numbers are not at hand so this is ball park numbers but example is each cell charged to 3.77V rather than 4.20V etc. Believe Tesla "Extended or Full(?) Range" charge likely uses a "Max or near max Voltage" charge/cell (if used frequently will shorten battery life) or is it "normal range" charge likely under charges cells to prolong battery life.

Battery University Site:
Good source probably for "generally applicable" information.
1) How to prolong battery

2) How to charge battery

wonder | January 14, 2013

Correction NCA refers to Nickle, Cobalt, and Aluminum.
Large part of battery composition and I think weight is Cobalt (as I understand it).

Believe Composition is: LiNiCoAlO2

Battery University Link on various Lithium-Ion Battery Types

wonder | January 14, 2013

Basis: My conclusion that Tesla Model S uses
Nickle Cobalt-Aluminum (NCA) Battery and "not"
Nickle Manganese-Cobalt (NMC) battery came from Tesla Motor Club Link below

But as always subject to error of internet!

Excerpt from Tesla Motor Club
The cells Panasonic (Matsushita) produces for the "retail market" uses NCA (under the new marketing name of NNP, it was previously marketed as NCA). And Tesla uses a "retail market" cell, specifically, the NCR18650A (the only 3100mAh 18650 battery that Panasonic makes). Tesla is not using some special formulation by Panasonic (I have not seen any evidence presented that they are, but there's plenty of evidence pointing to Tesla using specifically the NCR18650A, they even had a press release that said as much announcing Tesla was using Panasonic 3.1Ah batteries made at 300 mil. units per year AKA the NCR18650A).

Link shows Panasonic and Tesla Management holding cell that Model S will use

Link referenced:

Sounds like new acronym might be NNP
Here is link to Panasonic document

wonder | January 14, 2013

From Tesla:

Article above seems to imply Roadster rather than Model S but previous link, with same photo, seemed to imply Model S.

Link to Panasonic embedded in above

This doesn't seem to show same 3000 cycle study. So who knows?

wonder | January 14, 2013

Tesla Configuration Guy just said expect 70% of original capacity after 8 years or so. That is more what I've seen in the battery industry generally for end of life capacity.

schoendp | January 14, 2013

I appreciate all the discussion on this topic.

From reading the previous posts, it appears that (if you have time) charging on a standard 120V outlet is better for the battery than charging on a NEMA 240V outlet.

Is this correct?

sbern18 | January 14, 2013

So if I'm "topping off" and there will be hours before driving, should I lower the amps coming in? And if so, to what level, how do I make that calculation? Thanks in advance.

Brian H | January 15, 2013

2 points;
TM guarantees 70% after 10 yrs -- but expects the battery will do twice as well (100% margin allowed). I.e., 85%.

And, wonder, there is no nickle in the battery. Lotsa nickel, though! ;)

ddruz | January 15, 2013

Brian H, May I please ask you for the written source of your comment that "TM guarantees 70% after 10 yrs?"

There are no guarantees on battery capacity in the battery warranty language, which I'm sure you will recall generated a bit of an uproar on the forums after the battery warranty was released.

I'd be most grateful for the source of a written battery capacity guarantee from Tesla.

bp | January 15, 2013

Can we get any of the early Model S owners to comment about any changes they've seen so far in battery life?

With the onboard software, Tesla can provide a lot of help in managing battery life and optimally charging the car.

For example, if slower recharging is better to maintain capacity, the charging software could be told to do full recharges overnight, during a specific timeframe - and lower the recharging rate to achieve maximum charge, but at the lowest rate.

Another option would be to do what newer laptops do - and have a threshold that must be crossed before the battery will charge. I have a tablet and laptop that won't charge until the battery is below 95% in capacity. If the car is only driven a short distance in a single day (30 miles?) - then it might be better for the battery not to charge at all that night - and defer charging until more of the battery has been depleted - if the number of times the battery is fully charged affects lifetime.

As more vehicles are on the road - and Tesla continues to collect more data from operating vehicles - they will hopefully use that data to continue to refine their recharging recommendations - and the onboard software - and help all of use maximize the long-term capacity of our batteries.

jat | January 15, 2013

@bp - if any Model S owners can see any change at all in at most 3 months, then there is something seriously wrong. My 14-month-old LEAF has no measurable change in the battery after 10k miles.

Also, I think the "standard" charge setting does exactly what you describe, as it keeps you from fully charging the battery anyway.

Brian H | January 15, 2013

Yes, the documentation of early promises is sketchy. Early statements are not (yet) followed through on in writing, though the Tesla Facts page comes reasonably close. Various LiIon battery specialists have described and laid out LiIon lifetimes, with the caveat that temperature control (particularly prevention of overheating) is a dominant variable.

The unlimited miles/8-yr warranty on the 85kWh batteries corresponds to the figure above, as "70%" is the industry standard for end-of-life, though that would be still 60kWh, and degradation slows down after that point, according to the experts. So TM is promising the 85kWh battery will not fall below 70% in 8 yrs, no matter how far you drive with it! As long as they adhere to standard "end of life" determination. But no one has seen the fine print yet, of course.

(Interesting side note, is that an Alaskan Roadster owner reported about 40,000 miles so far with less than 5 or 6 miles of range loss, which is around 2%, in about 4 yrs of ownership. Cooling seems to help! Conversely, some AZ Leaf owners were reported to be suffering the consequences of inadequate (thin, hot?) air cooling, with severe range losses.
The owners' estimate their reduced battery capacity is at least 30 percent [some were seeing 50%], even though they claim they are driving in strict accordance with Nissan's owner's manual. They also showed CBS 5 News their dealership service records, which show high marks for properly driving and charging their Nissan Leafs.

According to Nissan, that 30 percent battery capacity loss shouldn't happen until after about seven years on the road.)

Note that Nissan was using 70% as its standard after 7 yrs, even with its much weaker cooling system. Industry standard?

Brian H | January 15, 2013

The phrase "industry standard for end of life" was referring to the LiIon battery industry generally, not narrowly automotive. It's early days, and Ownership says they're not likely to put anything that firm in writing until they've had longer track record to work from. But they do rate the battery tech and advances as their #1 strength and are committed and confident in that regard.

Brian H | January 15, 2013

typo: "had a longer track ..."

Brian H | January 15, 2013

Considering..."So TM is promising the 85kWh battery will not fall below 70% in 8 yrs, no matter how far you drive with it! As long as they adhere to standard "end of life" determination." may not be applicable to high mileage drivers; the service/warranty requirement is 12,500 mile or annual, whichever comes first, between "visits". An 8-yr 85kWh owner who drives 20K per year would not necessarily have a capacity level warranted, just a "no manufacturing defects" promise. It will be possibly/likely a matter of some contention in many cases what is "normal" and what is a "defect".