165k Miles Battery Degradation

[Alexander]

I need help. I'm trying to figure out how much my battery has degraded in the 5 years and 165k miles I've owned it. It seems like my range has fallen off a cliff recently and my 0-60 performance is just atrocious compared to what it used to be. The car just feels very weak over all and today I did road trip of 167 miles and barely made it. I started with a 100% SOC and ended with 9% after only 167 miles.

I did the math and it seems like my 85kWh battery can only store 71kWh now. So about a 16.4% loss.

Am I doing that math right?

If so, is a 16.4% loss in range normal?

Here's a picture of dash with the specs:

 

[MP3Mike]

What range is reported when charged to 90, or 100, percent? (That is how you calculate degradation.)

 

[IdaX]

According to this:

Tesla’s hacked Battery Management System exposes the real usable capacity of its battery packs

Your actual usable battery capacity was 77.5 kW-hr when new. With the numbers in your post and the photo that looks like 12.2% degradation. Maybe. It turns out this isn’t always real clear cut, as mp3mike before me suggested. The only real way to determine your degradation is to run it from 100% to shutdown. Not particularly recommended though!

Also: it looks like you’d stopped somewhere in the middle of your trip. For whatever reason, the Tesla trip meters don’t count energy lost to phantom drain. So the “kW-hr used” is a minimum...

 

[Tam]

...16.4% loss....

What's the rated mile when you charge it to 100%?

 

[Alexander]

Here's a screenshot I took 9 days ago when I charged to 100% SoC. This is rated range:

 

[Alexander]

I did the entire 167 miles in 5 1/2 hours only stopping 3 times. Twice for less than 10 minutes and a third time for 2 hours.

 

[Tam]

Here's a screenshot I took 9 days ago when I charged to 100% SoC.

The spec for a new Model S85 is 265 rated miles.

You lost 18 rated miles and now it can only charge fully to 247.

That's a loss of less than 7%.

That's just too miraculous for nearly a 165,000-mile battery!

 

[TacC]

Your Wh/mi is having a pretty big impact.

If I recall, rated mileage is based on 291 Wh/mi. You should be able to get another 20-30 miles out of a full charge by driving more efficiently.

 

[Troy]

I did the entire 167 miles in 5 1/2 hours only stopping 3 times. Twice for less than 10 minutes and a third time for 2 hours.

That's the issue. The trip meter won't include any consumption while the car is not moving. The 85 kWh battery has 77.5 kWh usable capacity when new. If you use the kWh method, your capacity is (61.9/0.9)/77.5= 68.8/77.5= 88.7%

However, it's better to calculate capacity using rated range at 100%. Assuming it displayed 267 mi when new, capacity left is 247/267= 92.5%. If you look at the chart here, at 165K miles the trendline shows 91.8%. Therefore, your capacity looks perfectly normal.

 

[ArizonaP85]

167 miles on that trip with 9% remaining games means 183 miles total range -- at 371 wh/mi, that's not too bad. Lifetime 386 wh/mi makes me wonder: how fast do you drive? I only see numbers like that going up long grades but you can't drive uphill all the time!

 

[Alexander]

Ok good! So my math was wrong.

My daily commute includes long up hill drives. I live in a higher elevation than work which is close to sea level and I admittingly tear up the roads getting to and from work. So 386wh/mi lifetime isn't surprising to me.

Yesterday was just shocking because I was driving slow the whole way in cruise control, with range mode turned on, no AC and the windows rolled up. I was driving as efficiently as possible. The only factor working against me was a 4,200 foot elevation change and a steep up hill drive at one of my destinations.

My car just feels very weak compared to how I remember it both acceleration and range wise. But the numbers dont lie. Glad to see my degradation normal.

 

[dark cloud]

Maybe something else? low tires? big headwind? dragging brake? someone hitched a trailer on the back when you weren't looking?

Yeah, that is some promising degradation: hoping mine has only 7% loss in 5 years at 264,000 km

Be happy!

 

[scole04]

Ok good! So my math was wrong.

My daily commute includes long up hill drives. I live in a higher elevation than work which is close to sea level and I admittingly tear up the roads getting to and from work. So 386wh/mi lifetime isn't surprising to me.

Yesterday was just shocking because I was driving slow the whole way in cruise control, with range mode turned on, no AC and the windows rolled up. I was driving as efficiently as possible. The only factor working against me was a 4,200 foot elevation change and a steep up hill drive at one of my destinations.

My car just feels very weak compared to how I remember it both acceleration and range wise. But the numbers dont lie. Glad to see my degradation normal.

4,200 feet positive elevation change??? Lol. Theres your lost range. There may be a drop in voltage from what the battery can pull and deliver to the motor but look at the BMS to be sure.

 

[Alexander]

Well I found at least part of the reason why my range felt so bad that day.

Yesterday on my way home I had my music turned off (which is a rare event for me) so when I pulled up my driveway I could hear something scraping that I didn't hear before. I got out and looked under the car and find this large plastic panel hanging down acting like a massive scoop. I zip tied it back into place. Have no idea what happened to the clips but after "repairing" it with zip ties, today I could feel a big difference in wind resistance.

 

[dark cloud]

Quite a few scrape marks there. Steep driveway?

 

[Alexander]

Quite a few scrape marks there. Steep driveway?

My car has seen a many thousands of driveways haha. You should see my rear defuzer... Even at max ride height I still scrap on some of the drive ways I have to go up for work.

 

[David99]

The underbody panels are known to come lose. In parking lots they have these stopper bumps. Unfortunately they are just at the height for the panels to get stuck and then tear off when you pull out. I have the same issue.

As for degradation, 247 miles on a full charge is OK for that age/mileage. The sluggish acceleration isn't, though. My car has 203k miles and a 100% charge is 239 miles. But my 0-60 times is the same as it was new.

 

[Alexander]

The underbody panels are known to come lose. In parking lots they have these stopper bumps. Unfortunately they are just at the height for the panels to get stuck and then tear off when you pull out. I have the same issue.

As for degradation, 247 miles on a full charge is OK for that age/mileage. The sluggish acceleration isn't, though. My car has 203k miles and a 100% charge is 239 miles. But my 0-60 times is the same as it was new.

Yea, I've gotten my under body caught on a lot of those parking bumps too.

The acceleration issue is harder for me to quantify because I don't have any data from when I first bought the car to compare it to. But it certainly "feels" slower. I think the 0-60 time for my car was advertised as 5.4 seconds. Right now I wouldn't be surprised if it was in the 6 to 7 second range.

I say that because a Honda Fit almost overtook me at a light yesterday. I needed to get in front of him to make a turn that was coming up and he needed to get in front of the person next to him to get on the freeway. So when the light turned green we both floored it and for a second it looked like he was going to overtake me. I eventually pulled ahead (or he braked because he had enough room to get over) but it was pathetic. My $100k car (when it was new) is now barely able to overtake a $16k commuters car?? Somethings wrong.

I have a mobile tech coming out to look at my car on Wednesday and plan to bring it up then.

 

[sorka]

Download powertools for ios, login, accelerate to 60 when charged at 90% and just after charging so your battery isn't too cold.

If you see anything near 320KW, you're car is making power fine. I can't tell you how many times in the past I thought some car of mine was making less power than it used to only to check it with an accelerometer only to discover it was all in my head. That said, you're probably down some power after 165K miles. I'm down 15KW after 85K miles.

Check your alignment if you haven't already as that can be a huge contributor to high wh/mile readings.

Your rated range displayed is EXCELLENT for 165K miles!!!

 

[ReddyLeaf]

...I say that because a Honda Fit almost overtook me at a light yesterday....

maybe it was a Fit EV.