Please Help me Understand Range

[Baxterdown]

Hi everyone,

I'm about to complete two months ownership of my pre-owned 2017 MX 90D. I typically drive 5-10 miles a day so range has never been something I've cared about. Until yesterday! I have my charge set to the top line on "DAILY" and usually leave my house with 200-206 mile charge (it varies every day).

Yesterday I left my house with 200 mile range and drove errands totaling 123 miles. I got home with 13 miles range left. I took a pic of the Trips screen, which showed the following since last charge:
- Distance: 123.2 miles
- Total Energy: 53.3 kWh
- Avg. Energy: 433 Wh/mi

Some info about the errands I ran and how I ran them:

• I left my house and drove about 45 miles to my first destination. About 90% of that was on the highway and I averaged 85 mph.
• On the second errand I drove 23 miles to the next destination. About 50% of that was on the highway and I averaged 60 mph.
• If I remember correctly, by the time I left my second destination I was already down to about 85 miles range left. I drove 46 miles to my next destination. About 90% of it was on the highway and I averaged 85 mph. I arrived at my third destination with 29 miles range left.
• My last leg was 14 miles and I arrived back home with 13 miles range left.

The weather in South Florida was pleasant yesterday. Sunny with a high of 82.

Not knowing anything about range, I estimate I got just a tad more than half the range I was supposed to.

Is this normal?

Thanks in advance for your insight,

Jose

P.S. Don't hesitate to ask for any additional information I can provide to help you guys enlighten me.

 

[RCM11]

Highway driving vs around-town driving are very different where range is concerned. You get lots of regenerative braking with around-town stop and go driving. The highway provides next-to none of this benefit. Was you AC cranked up? Did you stomp on the accelerator a few times passing cars, merging from on-ramps? Were windows rolled down on highway increasing drag? There are many variables that go into determining range, so some more information is needed. In summary, highway vs. around town is no-contest regarding effective range. You lose range on the highway more quickly.

 

[DCGOO]

Your energy use at 433 wh/mi seems very high to me. I get around 300 wh/mi in the (Indiana) summer months. You might want to make sure your tire wear is normal (not needing an alignment). Once you get your consumption under control, I would recommend changing your display over to the energy setting, (% capacity). It makes a whole lot more sense. Use the energy graph for estimating range.

 

[Rocky_H]

@Baxterdown You keep referring to what's on the car as "miles", and that's kind of why it's messing with you. Those are "rated miles". It's measuring the energy in the battery, but then dividing it by a fixed efficiency constant by what the EPA testing was. And if you realize a bit about how the EPA testing is, it's like your nearsighted granny driving, and never going over 55 mph, so it's a notoriously cautious and slow and efficient kind of driving, which most people don't match in their real driving. So people usually have two responses to this:
1. Switch it to % and don't ever think about it. (head in the sand)
or
2. Leave it on "rated miles" but be comfortable with the fact that it's always optimistically high by some decent sized fudge factor versus real miles.

And the other thing, which I think a couple of people mentioned, is that those meters on the screen of "since last trip" and "since last charge" only show the measuring while the car is in Drive. So any extra idle use will deplete some extra rated miles that aren't showing up in those meters.

 

[Harvey Danger]

Those are "rated miles". It's measuring the energy in the battery

This is the way.

If you are tying to get your actual-miles-of-distance-traveled to be the same as the rated-miles-of-energy-used, you will probably need drive in such a way that you achieve a consumption number under 300 Wh/mi in the trip meter. (In theory your target is 304, but in practice it will usually have to be even a couple percent lower than that, so.. 298?). Standard disclaimer applies: this really only applies to a warmed up car on a longish uninterrupted drive. If your average was over several days or involved a lot of short trips, it'll seem even worse. Anyway, 433 Wh/mi will use up battery "miles" way faster than you rack up odometer miles for sure.

So you can either leave your battery display as it is and mentally start adjusting your expectations regarding what a "rated mile of charge" means, or set it to percentage instead and just treat it like your cell phone (if it turns yellow, charge it).

Edit PS assuming your max "Daily" charge (ie 90%) is 206 rated-miles, you have a pack that can currently hold 229 rated-miles of energy at a 100% charge. When this pack was new, I believe Tesla claimed the 90D had a rated-range of 257 in 2017. So this comes to about 11% degradation in 4 years. Not scandalous, but noticeable.

 

[Baxterdown]

Hi guys, good morning. Thanks for all the replies, I appreciate your insight.

If I'm hearing your correct, the "miles" left is similar to an ICE car. They're not hard miles, how I drive is going to determine how many miles I really have left on that charge.

I have the graph on the right side of the instrument cluster as my default display, but I must confess that I have never understood it. And I have never bothered learning about it because I drive so little on a daily basis that I know I'll never use all the range in the car. I'm gonna have to read about it.

@RCM11, the windows were closed and the A/C was at full blast (probably at 7 or 8). I was definitely driving in a "spirited" fashion LOL!

@Harvey Danger, you bring up a good point. I have never fully charged the car! Since I haven't gone on any out of town trips, I've only charged it to the top daily line. I have to run another long errand on Friday. I'm gonna charge it to 100% tomorrow and see what it displays the next morning.

Thanks again!

Jose

 

[idoco]

It's very simple---->"...and I averaged 85 mph....". Speed kills range.

EPA range testing speeds:

"...This procedure uses the same EPA city cycle (20-mph average speed over 7.5 miles with 18 stops) and highway cycle (48-mph average speed, 10.3 miles) ... the most aggressive acceleration would be equivalent to an 18-second 60-mph time. Between city and highway loops, the test calls for a steady speed of 55 or 65 mph..."

Good news for your battery...it's fine. You started the trip at the high end of daily, which is ~70%. A 90D true usable capacity new is ~82kWh. So you started with your trip with 70% (57.4kWh). You used 53.3kWh so had ~4kWh remaining. Rated efficiency is ~310 w/mile. Hence the 13 miles "rated" remaining.

Bad news. Given that you were actually using 433 w/mile your "actual" range remaining was probably closer to 9 miles. And if that last leg was on the highway at 85mph you could easily be using 600+ w/mile. Which means you rolled into your driveway with less than 5 miles of range remaining

 

[idoco]

Addendum

The "rated" range on the instrument cluster is based on the "rated" range of the car. Not the actual range best on your current usage. If you want a better estimate then use the consumption screen. It's range is based on the "actual" usage over the last 5, 15, or 30 miles.

How to accurately predict range in a Tesla

How to accurately predict range in a Tesla

gregsramblings.com

 

[Bigriver]

@Baxterdown, thanks for asking this question with such an open mind and not a hint of “how stupid is this” that often accompanies people learning that “rated miles” is a whole different unit than “actual miles.” I endorse answers you have gotten above, primarily:

• Use the energy graph on the main screen to get a good estimate of actual mile range. This is the closest thing to the miles to empty estimate on ICE cars.
• Switch the battery display to %, as this is the closest thing to a gas gauge on ICE cars.
• If you want to extend the range, slow down!
• Tires do matter and not remembering if you have 20” or 22” rims…. smaller is more efficient.

I obsessed with this in my first year of ownership and still keep an eye on what efficiency I’m getting. Your data of going 123 actual miles and using 187 rated miles puts your day at 66%. That also includes any non-driving energy usage from things like sentry cam, which can be significant. For whatever interest it might be, this is some data I compiled of what the displayed Wh/mile is vs. my efficiency. While there is chatter in the data, I basically need to see less than 320 Wh/mile for my actual miles to equal (or exceed) my rated mile usage. Your 433 Wh/mile is off my chart (!) but an eyeball extrapolation looks like it would be relatively consistent with your 66% efficiency.

 

[Harvey Danger]

It's very simple---->"...and I averaged 85 mph....". Speed kills range.

Agree.

You started the trip at the high end of daily, which is ~70%.

Disagree. Where'd you get that?

A 90D true usable capacity new is ~82kWh.

Agree. Where'd you get that? I know where I always turn to get these numbers (I've basically boookmarked a famous TMC post with a handy table showing these numbers for various models, curious if that's where you are getting it also)

Rated efficiency is ~310 w/mile.

Disagree. Where'd you get that? (I usually refer to the same post mentioned above for these numbers)

Looks like we totally agree on how to think about range generally. Just wondering if I should be using different numbers.

 

[ngng]

I'm

Agree.


Disagree. Where'd you get that?


Agree. Where'd you get that? I know where I always turn to get these numbers (I've basically boookmarked a famous TMC post with a handy table showing these numbers for various models, curious if that's where you are getting it also)


Disagree. Where'd you get that? (I usually refer to the same post mentioned above for these numbers)

Looks like we totally agree on how to think about range generally. Just wondering if I should be using different numbers.

80-90% is fine for daily.

 

[ngng]

@Baxterdown, thanks for asking this question with such an open mind and not a hint of “how stupid is this” that often accompanies people learning that “rated miles” is a whole different unit than “actual miles.” I endorse answers you have gotten above, primarily:

• Use the energy graph on the main screen to get a good estimate of actual mile range. This is the closest thing to the miles to empty estimate on ICE cars.
• Switch the battery display to %, as this is the closest thing to a gas gauge on ICE cars.
• If you want to extend the range, slow down!
• Tires do matter and not remembering if you have 20” or 22” rims…. smaller is more efficient.

I obsessed with this in my first year of ownership and still keep an eye on what efficiency I’m getting. Your data of going 123 actual miles and using 187 rated miles puts your day at 66%. That also includes any non-driving energy usage from things like sentry cam, which can be significant. For whatever interest it might be, this is some data I compiled of what the displayed Wh/mile is vs. my efficiency. While there is chatter in the data, I basically need to see less than 320 Wh/mile for my actual miles to equal (or exceed) my rated mile usage. Your 433 Wh/mile is off my chart (!) but an eyeball extrapolation looks like it would be relatively consistent with your 66% efficiency.
View attachment 666417

If you're getting low to mid 300 Wh/mi you're just crawling around. 75mph on the highway and some stomps on the throttle easily break 400.

 

[Harvey Danger]

80-90% is fine for daily.

I understand general best practices but the OP said 'the top line' of daily and that gives me very specific information about the percentage he charged to, right? Is it not 90 exactly?

 

[ngng]

I understand general best practices but the OP said 'the top line' of daily and that gives me very specific information about the percentage they charged to, right? Is it not 90 exactly?
View attachment 666468

I was replying to the quote about 70% being "top of daily".

In response to you, yeah, those lines are 10% steps.

 

[Bigriver]

If you're getting low to mid 300 Wh/mi you're just crawling around. 75mph on the highway and some stomps on the throttle easily break 400.

Well over half of my driving is on the highway. Typically have cruise set between 72 mph and 75 mph for 70 mph speed limit. I respect work zones and slow for those, but also stomp it to get past any vehicle on my a$$. Had one particularly good 380 mile trip last fall where Tesla showed right at 300 Wh/mile for the day. It’s a trip I do often and don’t know why it was so particularly stellar that day. 330 Wh/mile is more typical for non-winter but that is still below mid 300’s.

Here was associated stats from Teslafi.

 

[peety3]

Let me paint an analogy: years ago I was a volunteer firefighter. When it's time to run into a burning building, firefighters use those backpack-style "Air Paks" which are usually rated as 30, 45, or 60 minute packs. Guess what? The 30-minute pack has 45 cubic feet of air compressed into the tank. Take a breath...now it's maybe 44.8 cf. Take another breath, now it's maybe 44.6 cf. Breathe a lot in a short period of time, and you'll exhaust that 45cf in a jiffy. Some well-conditioned firefighters can knock down a lot of fire in 12 minutes and burn through that 30-minute pack, while others might stretch the tank to 35 minutes.

Your car has a 75, 90, or 100 kWhr battery, or something like that. Use some juice, and the battery goes down a bit. Use a lot, and it goes down fast.

 

[jjrandorin]

Agree. Where'd you get that? I know where I always turn to get these numbers (I've basically boookmarked a famous TMC post with a handy table showing these numbers for various models, curious if that's where you are getting it also)

We have a sticky post in the model 3 section which explains how someone can calculate their batteries capacity using only the information on the tesla screen. Anyone can do it very easily.

Its here:

Calculating Your Battery's Estimated Capacity Using the Car's Energy Screen

Re posting here and making this a sticky post so it doesnt get lost. @AlanSubie4Life originally posted: =========================================== (originally posted by @AlanSubie4Life. Original thread this appeared in can be found here: ( 2021 model Y scan my Tesla battery size)...

teslamotorsclub.com

 

[Harvey Danger]

Yep. Love that post. I have linked to it many times. But my question stands. How did a person conclude, based on no information from the energy app, that the OP's pack was supposed to hold a maximum usable capacity of 82 kWh when it was new (ie four years ago)? I agree with this assessment, just comparing notes...

 

[David29]

FWIW, here is Tesla's web page with their own tips on "Range."

Range Tips | Tesla Support

Your Tesla vehicle continuously monitors its energy level and proximity to known charging locations to provide range assurance. To maximize efficiency, it is important to know the factors that impact range and the recommended ways to reduce energy consumption.

www.tesla.com

 

[Baxterdown]

Hi guys, thanks for all your replies!

I charged the car all the way to 100% on Thursday night. I left my house on Friday morning with 227 miles range. So if my car originally had 257 mile range. 4 years (and 4 months) later, I get 88% charge. Which means, my battery has lost 3% capacity per year. It looks like @Harvey Danger was right on the money!

I’m gonna go with his assertion: not scandalous, but noticeable. I don’t know that I have much of an argument with Testa. Or, do I?

On a separate note, and apologies for going off-topic, I had no idea that regenerative breaking doesn’t work/activate with a full-charge. I freaked out when I started driving and the car kept going when I approach the first traffic light! It took me a second to get used to it.

BTW, I got home with 89 miles range left after my 80 mile round trip errand. Same scenario as the original post. Mostly highways, AC was blasting and I was hauling ass on the highway, LOL! So, I guess not too shabby.

Thanks again for sharing your thoughts,

Jose