200 mile daily commute - effect on battery life?

[yobigd20]

Question for the battery tech gurus -

First, let me just say yes I have a ridiculous daily commute. It's usually 2.5 hours each way by car+train+metro. (5 hr commute per day). I'm looking to move closer eventually, house is going up on market this month, so not looking for comments like 'you should move closer' etc etc.

Before I had the MS, I would drive to a train station which was 46 miles away, then train + MTA. 92 mile daily commute.

Now that I've had the MS, I've been driving into the city daily. It's 100 mile commute each way, so 200 miles daily commute. Instead of 2.5 hrs, my commute is now 1:30/1:40ish if I leave early enough. Enough to make a difference.

That being said, lets go under the assumption the housing market really sucks (not a bad assumption right now, lol) and it takes 3 yrs to sell (as it may take a while in this market to sell my house just assume this commute is 'indefinite' for now,).. I'm wondering what the effects of the battery life would be if I kept doing this. That's basically 4000 miles a month. Plus weekend driving, assuming that I am driving 50000 miles/year.

From what I've read from Tesla somewhere (owner's manual?), the battery should lose about 1% per 10000 miles. I guess that's about 2.5 miles range loss per 10000 miles. Does that mean at 100,000 miles we'll lose 25 miles range and our standard charge range will be about 220? Is that accurate? Does this 'level off' at all? - meaning that does the 'degradation rate slow down' or is it a linear/constant loss? So at 300,000 miles (75 miles range loss?) will we have 170 miles range on standard charge? I'm wondering if the degradation rate slows down over time, remain constant, or perhaps even increase? Does anyone know how many miles it would take for 'complete failure' or 'degraded enough to need a replacement'?

Sorry - lots of questions. But I'd really like to know the answer to these as it's pretty important to know the actual expected battery life. There are articles I've read online that say things like 'lithium ion EVs will need to have their batteries replaced every 100,000 miles' but is that all just BS? If that's true then I don't want to be looking at replacing the P85 battery every 2 yrs, lol.

 

[jhs_7645]

This is by no means a technical answer (I'm sure battery folks will weigh in soon), but my two cents is that a lot of miles on the battery are exactly what you want. The more miles you drive that car the better it is for your gas bill, the environment, your driving enjoyment all of it. If you wear out your battery because you used it to much is that a bad thing? Take the money that would have gone to gas for that 50,000 miles/year and pre-purchase a battery. Would you prefer to buy the car and leave it in the garage?

My advice is simple: I say, you bought the car.. use the car..

 

[FlasherZ]

There are the "typical" studies and then there are anecdotes; unfortunately, I don't think there's enough real-world data to be able to identify true long-term patterns at the mileage we're all looking at.

The battery degradation thread speaks of a tested, typical ~24% decline after 500 cycles of each cell, for the cells that Tesla uses.

There is anecdotal data from a Roadster driver (I realize different chemistry), quoted recently in an investment article, that is seeing a 30% decline after 160,000 miles @ roughly 40k per year, which is close to your scenario.

I have heard other rumors such as Tesla's long-term testing of a model S that has significantly less degradation, but no published data, only rumors.

I don't drive enough to give you any personal data points -- after 5,000 miles and just over 5 months, immediately after charge completion, my model S still shows 240 miles.

I suspect you're going to be one of the guinea pigs for published data.

 

[Rodolfo Paiz]

My advice is simple: I say, you bought the car.. use the car..

I'm with him: use the car.

I don't think anyone really knows what'll happen in the long term to a Model S battery that gets driven 50,000 miles per annum. I think you'll lose some capacity over the miles and the months, but I find that frequent use is good for battery life, so I'll speculate that you'll see degradation but that it won't be terrible. Besides, you have an 8-year, unlimited-mile warranty on that battery from Tesla which may provide some relief if degradation gets serious. And of course, you can keep track of what your battery is doing and change your commuting habits in six months or a year if you see the battery's capacity degrading. Lastly, if you bought a P85 today, you are probably not the guy who'll keep his car for 8 years anyway... you like leading edge and will probably change out the car at three or four years of age.

All of those "thinking points" are what say to me: use your car and love it.

 

[dsm363]

You will definitely want a place to charge at work so you can do a standard charge each day. Not sure how much faster it will degrade with heavy use.

 

[Citizen-T]

I'm with the guys above: pound the miles on and save the gas money to buy a new battery if/when the time comes. I'm not sure how you value your time, but to me, the time savings alone would justify the wear and tear on that battery. You are coming out way ahead once you factor in fuel savings, IMO.

 

[dsm363]

Is there even a battery replacement option anymore?

 

[mhpr262]

The battery degrades due to age and to cycling. The more miles you put on the car in a given amount of time the less capacity you lose without benefit to aging so you actually get more "value" out of your pack than the average driver. I have read a reported statement of a Tesla engineer claiming they had a 85kwh pack in their lab that had been undergoing repeated cycling for 165.000 simulated miles and it was still at 85% capacity.

If you have the opportunity to charge at work and keep the charge cycles shallow you numbers will probably be even better (I assume the pack in the laboratory was being tested under pretty harsh conditions (deep discharges), the data wouldn't be worth very much otherwise).

That commute is brutal ...

 

[yobigd20]

The battery degrades due to age and to cycling. The more miles you put on the car in a given amount of time the less capacity you lose without benefit to aging so you actually get more "value" out of your pack than the average driver. I have read a reported statement of a Tesla engineer claiming they had a 85kwh pack in their lab that had been undergoing repeated cycling for 165.000 simulated miles and it was still at 85% capacity.

If you have the opportunity to charge at work and keep the charge cycles shallow you numbers will probably be even better (I assume the pack in the laboratory was being tested under pretty harsh conditions (deep discharges), the data wouldn't be worth very much otherwise).

That commute is brutal ...

Funny you mention, I saw this article today: Tesla offers 8-year warranty on Model S battery pack | Detroit Free Press | freep.com which mentions:

“We don't think anybody could put enough miles on to kill the (85 kwh) pack. That could turn out to be wrong, but we have half-a-million miles on one in the lab,” says Tesla CEO Elon Musk. “Even the 60 kwh customers will be able to take it well over 200,000 miles.”

though he doesn't mention what the degradation is at 500,000 miles...

but I guess that's good news for me. As far as any "savings", hardly bc the NJT tolls (both directions) + NYC bridge toll + daily parking in NYC is > $50 per day lol. I would never consider this if I had to pay for gas too. I'm still waiting on my green ezpass for some relief there but still...NYC madness...

Lastly, if you bought a P85 today, you are probably not the guy who'll keep his car for 8 years anyway... you like leading edge and will probably change out the car at three or four years of age.

This car better last me 15 years!!! lol while yes, i'm a techie (software engineer) and love to have all the latest gadgets, getting a P85 was definitely a stretch (I actually didn't tell the wife until AFTER I bought it..."better to ask for forgiveness than permission" HAHA). I talked myself up, starting with the 40,then 60, then 85, then oh well the hell whats another $10k after that but yes, as this was about 3x more expensive than any other cars I've bought, I'm hoping it last 3x longer (my other two lasted for 7 years each sooo this better last for 21??) well ok maybe not that long, but at least 10 hopefully. Well, I'll be 40 in 8 years so maybe I'll have another mid-life crisis around then

 

[Ardie]

yobigd20,

Hie thee on over to the following blog:
ActiveE Mobility: Driving an Electric BMW 1-Series

Tom Moloughney (who checks in here from time to time - I'll apologize now for stealing his thunder) drove the electric BMW Mini-E during their test program, and currently drives the electric BMW ActiveE during its current test program. He puts on over a hundred miles a day, electrically. Over 100,000 miles total, and still racking 'em up. Keeps meticulous records about it, too. And writes a blog about his experiences to share with the world. What a guy.

And what a coincidence. He recently wrote about the worries of battery degredation (i.e. the loss of battery capacity), and has a nifty graph and everything.

My take on this: You don't buy an electric car to *not* drive it.
Yes, the battery will lose some zip over time, but hey, so does a gas engine. Pistons rings wear out, valves need grinding, cylinders need re-honing.
So I consider the degredation of the battery similar to the degredation of a gasoline engine. Each one has its service life, and you can baby each of them to make them last a bit longer. The babying techniques are different, that's all. No biggie.


So Keep Calm and Carry, er, Drive On.


-- Ardie
Another ActiveE driver

 

[MichaelS]

Another point to remember is that Li-Ion batteries degrade just sitting there. They have an actual shelf life. So drive and enjoy your car. And condolences on your killer commute.

 

[Daniel Scherer]

The battery degrades due to age and to cycling. The more miles you put on the car in a given amount of time the less capacity you lose without benefit to aging so you actually get more "value" out of your pack than the average driver. I have read a reported statement of a Tesla engineer claiming they had a 85kwh pack in their lab that had been undergoing repeated cycling for 165.000 simulated miles and it was still at 85% capacity.

If you have the opportunity to charge at work and keep the charge cycles shallow you numbers will probably be even better (I assume the pack in the laboratory was being tested under pretty harsh conditions (deep discharges), the data wouldn't be worth very much otherwise).

That commute is brutal ...

I do 214 round trip twice to three times each week with a 5 hour layover to plug into A 14-50 at work. This tops me off for the trip home. No range anxiety with this set up. 300,000 mile battery life I think.

 

[mhpr262]

300,000 mile battery life I think.

At least ...

I have put 20.000 miles on my Fiat in the four years that I have owned it, 300.000 miles would take me 60 years ...

 

[yobigd20]

let it be known that the public has spoken ...

it is done. i canceled my train/parking/MTA tickets after this month. I will now be a 200 mile RT daily commuter.

Now onto the next item ... I am looking at getting an Escort Passport 9500ci ... lol

 

[JohnQ]

@yobigd20
And when you sell your house move on up to CT. You can drive or take the train but it's more pleasant and you've already collected your NJ sales tax break.

 

[FlasherZ]

Lastly, if you bought a P85 today, you are probably not the guy who'll keep his car for 8 years anyway... you like leading edge and will probably change out the car at three or four years of age.

Some will be that way, some won't. I anticipate keeping the model S for upwards of 8 years or so (I used to be of the "4 year max vehicle life" camp, then I found myself with an 8 year old Impala and 9 year old Suburban).

 

[Babylonfive]

I'll go further. I expect to hold Nikki forever. <sigh>

 

[deonb]

let it be known that the public has spoken ...

it is done. i canceled my train/parking/MTA tickets after this month. I will now be a 200 mile RT daily commuter.

Now onto the next item ... I am looking at getting an Escort Passport 9500ci ... lol

Do you have a way to charge the car in the city? If not, you won't need the radar detector. (If you drive fast enough to need one, you won't have enough range to make the trip.)

 

[yobigd20]

Do you have a way to charge the car in the city? If not, you won't need the radar detector. (If you drive fast enough to need one, you won't have enough range to make the trip.)

lol yes I charge in the city. And you're right. I get there with about 105 miles left. Ill leave you to speculate how fast I must be going to use 140 miles range to go exactly 100 miles.

 

[gray]

lol yes I charge in the city. And you're right. I get there with about 105 miles left. Ill leave you to speculate how fast I must be going to use 140 miles range to go exactly 100 miles.

I see you live in New Jersey. No need to speculate.