Impact of battery life/capacity on daily distance...

[SCW-Greg]

Not that this is based on any real numbers, but I'm wondering if the battery life/capacity say degrades at .5 to 1% per month, or over the course of two years 12 to 24% of its original capacity... on a 85kWh pack, this means a loss of 3 to 6 miles in max distance each month.

It will also be interesting to see how packs hold up for those who live in AZ, TX, etc (thinking scorching summers), compared with those say in IL (with bitter winters), or even with those living in consistent but more moderate temp zones. How in the real world, heat and cold will affect the immediate performance distance, as well as the longer term life/capacity of the battery.

Most of our driving will be capped at 60 miles per day, but 6 to 8 weekend trips per year traveling to Seattle (180 miles one way), or Central Oregon (115 miles one way). Each trip is about 3 hours. Not counting mid range trips to the beach. At some point, the capacity of the battery will threaten some of these trips, particularly if I drive like ICE traffic.

Now looking to swap a couple cars, save some cash, and reserve my S soon.
Greg

 

[Lyon]

Greg,

I'm not an expert, but from my understanding, battery range degradation is not necessarily a linear thing. Basically, the battery will lose a certain percentage of max range in the first four years or so and then the rate (percentage of remaining total) of loss will go down.

Also, everything that I've seen makes me think that your hypo of .5-1% loss per month is WAY too high. I can tell you that the experience of the Roadster owners around here has not been a loss of 12-24% capacity in two years.

You from the Portland area? I'm thinking that an 85kWh pack should give you you the range to make the Seattle trip no problem. The Eastern Oregon trip will be even easier because you'll be off of the freeway and onto the lower speed highways for much of the trip.

Tesal has said that heavy use of the HVAC could reduce range by about 10% so about 30 miles on the 85kWh pack.

 

[SCW-Greg]

@lyon... Yep from the PDX area. Encouraging to hear that loss is much better, ie not as bad as I hypothesized. Of course we're all also expecting significant improvements in future packs too. No doubt with firmware updates, aerodynamics, battery chemistry, etc that Tesla will have it achieving 400 mile range soon.

 

[dsm363]

Yeah, that level of degradation has not been seen in the Roadster at least and would likely not be seen in the Model S as it should only improve on that design. That would mean at most a 60% reduction in 5 years which would really anger people and make the car not really useful to many. It looks like people have seen about a 5% hit in 3 years or so but there is a thread about that on the Roadster side.

 

[Doug_G]

From what I've heard, Roadster pack degradation correlates mainly to how old the pack is, not how far it has been driven. You might see 2% degradation after a couple of years.

 

[donauker]

From what I've heard, Roadster pack degradation correlates mainly to how old the pack is, not how far it has been driven. You might see 2% degradation after a couple of years.

With just over 42,000 miles on my Roadster in 3 years and 2 months, I am seeing a 10% degradation.

I would be very interested in hearing of other Roadsters with over 40,000 miles that are seeing significantly less then 10% loss.

 

[ElSupreme]

I am expecting the 12-24% degradation (really about 10-20%) after 5 years and about 80k miles. Standard charging every day, and range charging maybe once a month or so.

At least that is my hope. I think that the Model S packs will do a little bit better than the roadster packs, as they will be taken care of a little bit better.

 

[donauker]

I think that the Model S packs will do a little bit better than the roadster packs, as they will be taken care of a little bit better.

In what way?

 

[Rifleman]

Hopefully we can get some answers on this soon. In my mind, pack degradation is make or break for the 40 kWh pack, as a 30% due to pack degradation would turn the vehicle into a Nissan leaf, and renders the range in standard mode to short for many drivers daily needs.

 

[ddruz]

+1 Rifleman. It would be very helpful if Tesla produced a blog article with definitive information and rules of thumb for estimating degradation. It is particularly pertinent for those hoping to suffice with the 40 kwh pack.

 

[SCW-Greg]

Good to hear guys, that pack degradation seems to be far less than I hypothesized. I was just taking an example from other Lithium-ion experiences (not from Tesla's experience).

This leads to the big looming issue, to mitigate everybody's EV concern, is the option for battery swapping (leasing), and/or significant improvements in overall tech where in say 5 years new packs will offer 30, 40 or even 50% increase in capacity - while lowering the overall replacement cost.

 

[bonnie]

I think your answer lies in looking at how few Roadster owners are worrying about this ... afaik, we've all experienced minimal degradation, so this has become a lowered concern for most of us. Definitely a lowered concern for me. I bought the battery replacement option that was offered for my Roadster, but don't know if I'd do the same today.

 

[richkae]

I have gathered data from a few Roadsters over in the Roadster Owner Based Study of Battery Pack Capacity Over Time thread.

I will try to post a full accounting of all the data that I have in the next few days, there is not yet a large sample size but:

There are 3 or 4 Roadsters that have 35k+ miles and the worst degradation is about 10% at over 50k miles.
There is one 3 year old Roadster with minimal miles that shows less than 1% degradation.
Many Roadsters up to 3 years old with up to 24k miles that show minimal ( 0-3% ) degradation.

My car is almost 3 years old, has almost 24k miles and is within 2% of new.
Hopefully over the next year or so a lot more cars will start to get to the 40k+ mile mark and we will have more data.

 

[bonnie]

I have gathered data from a few Roadsters over in the Roadster Owner Based Study of Battery Pack Capacity Over Time thread.

I will try to post a full accounting of all the data that I have in the next few days, there is not yet a large sample size but:

There are 3 or 4 Roadsters that have 35k+ miles and the worst degradation is about 10% at over 50k miles.
There is one 3 year old Roadster with minimal miles that shows less than 1% degradation.
Many Roadsters up to 3 years old with up to 24k miles that show minimal ( 0-3% ) degradation.

My car is almost 3 years old, has almost 24k miles and is within 2% of new.
Hopefully over the next year or so a lot more cars will start to get to the 40k+ mile mark and we will have more data.

Helpful summary, thanks.

 

[ElSupreme]

In what way?

Mostly assumption, but I think generally accepted across these forums. Improved temperature management and refinements from the Roadster. Probably not much but I bet there are some improvements.

 

[SCW-Greg]

Great feedback Richkae, thanks! No doubt the S will be treated as more of a family sedan, and will rack up the daily use and miles quickly. Serious data will come from this pool, and from this pack form factor too.

 

[bonnie]

Great feedback Richkae, thanks! No doubt the S will be treated as more of a family sedan, and will rack up the daily use and miles quickly. Serious data will come from this pool, and from this pack form factor too.

Not so fast .

You'd be surprised how many Roadster owners (myself included) that use their Roadster as their daily driver. Over 15K miles on my Roadster since Feb 2011, just under 3K on my Prius during the same time period.

 

[SCW-Greg]

Oh not to doubt you for a moment Bonnie1194! If I had a Roadster I'd be right there with you in mileage - it would be my primary car. Heck any EV will become my daily commuter, and hopefully my highway cruiser too. I'm just saying the S will (in general) be used much differently than the Roadster. :smile:

 

[bonnie]

And all I'm saying is 1) that was directly applicable data from Richkae, and 2) many more Roadsters in that pool of data are being used exactly the same way that the Model S will likely be used.

Very few of us keep them parked in the garage. We DRIVE them. Any excuse will do. We drive to work and to the store and pick up friends and drive on the freeway and on backroads and in stop and go traffic and in the rain and in the heat and even in a hailstorm. I wouldn't expect the data to be significantly different. The only difference is you can fit more in an S than a Roadster. But I don't anticipate there will be a significant difference in usage model. That's all I'm saying.

 

[gg_got_a_tesla]

We drive ... to the store ...

Even for that trip to Costco?! Toilet paper rolls in the lap, anyone?!

I get your point, Bonnie, but, I do suspect that the Model S will take a bigger 'beating' from a much broader demographic of drivers and usage patterns. School carpool runs, those Costco trips, 3+-member-family weekend trips and so on.

So, it's very conceivable that the battery pack behavior over time might be significantly different from that seen on the Roadster on average... for that reason, the 40 kWh pack could be a non-starter for a large cross-section of folks who definitely wouldn't want to end up with a 'Leaf' after a few years.