Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[SammichLover]

Not nihilistic at all.

You sound exactly like the people saying a few weeks ago we didn’t -know- all these Canadian Prairies & ND SC were V3 because Tesla hadn’t officially announced it. LOL

Whatever you want to call that nonsense. it is that.

 

[5_+JqckQttqck]

 

[rad1027]

Lol, if range indicated was truly based on driving habits, my estimated range would be 200 miles instead of 310.
No, that’s not what Tesla is doing. They do have an estimated value based on driving habits but that is not shown in the car, it’s available only through their API.
As for the charging to 100%, it takes an extra amount of time starting around 95% to rebalance the pack. That’s why you might see 30 minutes remaining, it doesn’t mean there are more miles of range to be gained.

This. I drive very “accelerator aggressive” at times before this software update and my 90% charge was consistently 277 miles. After the update, which is the only changing factor, I suddenly have a slight loss when I charge up to 90%.

 

[Stellavator]

You sound exactly like the people saying a few weeks ago we didn’t -know- all these Canadian Prairies & ND SC were V3 because Tesla hadn’t officially announced it. LOL

Whatever you want to call that nonsense. it is that.

I don't think you read my original post. Feel free to call me names, but ad hominem attacks are weak. And, you keep using that word. I do not think it means what you think it means. I never said that there can be no truth and life is meaningless.

My original point was simply that @BZM3 was wrong to assert conclusively that the rated range was driver-specific. The guy was yelling that everyone on this thread are idiots because we are trying to understand whether there is real battery degradation. I suggested no longer reading the thread.

Do you have an opinion or something to contribute on the topic of the thread, or are you just here to toss insults?

 

[5_+JqckQttqck]

I don't know about driver specific - more like model specific. I think they're being more realistic than the EPA rated numbers. All the DM 3LRs have been nudged down a good 20kms after V10.

 

[AlanSubie4Life]

The item in the video that really catches my eye is where he talks about the "constant" being changed to hide the amount of loss.

The constant for the AWD has not changed in 2019. I have data from February 2019 and from now. It's the same 230Wh/rmi (245Wh/rmi charging) for the AWD that it has always been.

I don’t know as some of those skeptics don’t work for Tesla. Yet they also could be misinformed.

We certainly could be. However, it's easy to measure the constant yourself and determine whether the battery gauge miles display depends on driving habits. It's quite definitive; it proves that the displayed number of miles next to the battery icon does not depend on driving habits (you can do it a few times with dramatically different efficiencies just to prove it to yourself). You can also look at the charging screen and swap between distance and energy display settings and see how the Wh added and the miles added are always in a fixed relationship. No need to take my word for the "proof" - you can just check it yourself.

There are of course other ways Tesla could fudge things and keep the constant the same - they could scale the Wh displayed dynamically. But then peoples' efficiencies would be all over the map, all the time, for the same drive. It would be very noticeable. And the discrepancies would show up in recharge event data for those people who monitor such things.

I think it's reasonable to think that the Wh units shown consumed on the trip meter are reasonably consistent in definition and are not scaled dynamically over time. With that assumption, measurement of the constant tells the story.

 

[Eldanon]

Exactly the point i have been trying to make. getting a lot of push back on it though in this thread, not sure why!

Likely because you're somewhat clueless =) The rated range doesn't depend on your driving style, doesn't depend on the weather outside, doesn't depend on your horoscope or anything else that is unique to you. It is a very straightforward calc of energy stored divided by fixed energy per mile (that's the same for everyone). Ok, seems Tesla might be messing a bit with that constant of how many watts per mile you need but generally that has stayed constant.

The rated range obviously doesn't mean that's how many miles you'll be able to drive. That DOES depend on your driving style and all that. But the number of miles that show up in the top left corner does NOT depend on anything but the actual energy stored.

For a lot of people after last few software upgrades the ability of the battery to store energy has IMMEDIATELY dropped by 5-10%. It's doesn't need to be "recalibrated" or anything along those lines. Tesla needs to be up front and tell us what they found and why they're reducing the capacity of our battery packs intentionally. Likely this is a safety concern but they're trying to cover this up and that's not the way to do it... it'll come out, it'll be less painful if they step up to the plate and tell us what's happening themselves.

 

[KenC]

So after rebalancing, I will still be capped at 290 is what you mean?

The range gauge could be, but you can certainly drive further, depending upon how you drive.

 

[SammichLover]

I don't think you read my original post.

.
That’s a hoot for you to make that [incorrect] assessment given apparently you haven’t [competently] read the definition for ad hominem , or my posts.

Feel free to call me names, but ad hominem attacks are weak

Lol

Do you have an opinion or something to contribute on the topic of the thread, or are you just here to toss insults?

Time for you to check the mirror.

 

[AlanSubie4Life]

It is a very straightforward calc of energy stored divided by fixed energy per mile (that's the same for everyone). Ok, seems Tesla might be messing a bit with that constant of how many watts per mile you need but generally that has stayed constant.

Just for the record, I can say for sure (since I have data) that the consumption constant (Wh per rated mile) for the AWD has not been changed since at least February 2019, before any of this funny business started. It's 230Wh/rmi for discharge and 245Wh/rmi for charging (this is only applicable to AWD; the constants are lower for all the other variants). Anyone can measure it.

I would think those people with long-term TeslaFi logging would also be able to easily show that the Wh/rmi constant has not changed (though it would be dependent on properly interpreting the way TeslaFi is reporting the data).

What the exact reason is for the reduction in available capacity above 0 rated miles, I don't think anyone can really say for sure here (not sure why there is a sub-argument about that here). But we can say that many people have experienced reduced capacity above 0 rated miles; rated miles are all you really need for that.

 

[AlanSubie4Life]

Exactly the point i have been trying to make. getting a lot of push back on it though in this thread, not sure why!

Of course, the available rated miles are an estimate generated by the BMS of how much energy is contained in the batteries, and Tesla tries to make sure it is as accurate as possible (so it doesn't drop from 30 rated miles to zero instantly, for example).

However, the fact that the rated miles available is an estimate does NOT mean that the number of Wh per rated mile differs on a per-user basis. There is no evidence that it does, for those vehicles with a properly functioning BMS. People can measure it.

How to square this? (This is speculation on my part.) I think basically, there is a bit of "slop" at the bottom of the battery (below zero rated miles), which Tesla hangs on to. When you get close to or below zero, the car will shut down at some point, but there will be a little energy left. If there are errors in the BMS that are during the discharge (would be "discovered" at the very end!), a little bit of this margin might be "dug into" to make sure that you do get the predicted available energy out of the battery that is shown to you (if everything is working properly) and you don't get premature shutdown.

Then, when you recharge, it will "simply" start counting how much energy has been placed into the battery. The number of rated miles displayed is this energy divided by the Wh/rmi constant (on the charging screen 245Wh/rmi is used; not the same as the discharge constant). It's far from simple, of course, since there is rebalancing, etc. that takes place. But that simple formula applies still.

This is presumably why "cycling" of the battery is sometimes recommended - it allows the BMS to start from a low state of charge and really keep track of how much energy it put into the battery - which sometimes results in a better count of the energy available (and a change in your projected 100% rated miles).

But the situation remains that, as far as I know, everyone with an AWD will measure 230Wh/rmi during a discharge (when the test is conducted in a valid manner). There are of course probably a few outliers where the BMS is really confused, where this relationship may not hold for a particular discharge. But I personally have not seen that data from anyone posted here.

 

[dhrivnak]

Interesting as our car LR is over 19 months old with 28,500 miles. I normally Charge to 90% and still get 285miles better than when new thanks to the Range bump.

 

[jamnmon66]

I wonder if there was a bad batch of batteries last September. I'd need to re-read the entire thread to confirm but all of the build dates of the problematic cars was Sept. '18 IIRC. Might be worth everyone with bad degradation stating their build dates.

For another data point, I have a 5/18 build date RWD LR with 26k miles. Charged to 100% yesterday for a road trip and it showed 309 miles. Showed 311 when new. Highest ever was 318 after the 325 mile announcement but it fairly quickly went back to around 310 +/- 2-3 miles. I don't use TeslaFi so this is just from the occasional 100% charge or doing the math from a lower charge level. I don't remember ever seeing/calculating less than 306 miles.

I usually charge to 70-75% daily unless I know I'm going to need more range. I've driven two 4000 mile road trips + the one that I'm on which is just from Denver to Santa Fe. Lots of Supercharging on the road trips but just charging in my garage otherwise (HPWC).

My wife has the same car as me with only 11k miles on it. She took delivery in Sept. '18 so the build date was probably Jul/Aug. As I mentioned, we're on a road trip so I can't compare miles to % on hers right now. I'll check that out when we get back.

 

[ChrisH]

Hmmm. I haven’t changed my charging habits but my charge to 85% gives me 272 miles and it’s been that way for months.

 

[AlanSubie4Life]

Charged to 100% yesterday for a road trip and it showed 309 miles.

Since presumably the constant changed when they went from 310 to 325 rated miles (does anyone know what the change in the constant was?), it looks like you have about 5% degradation (309/325), which is in line with a lot of the other reports here.

Just because you have more rated miles than someone with an LR AWD doesn't mean you have less degradation, because the constants are different; 310 rated miles on the LR RWD is equivalent to about 300 rated miles on the LR AWD in terms of energy available.

That being said the LR RWD is so darn efficient, that number of rated miles would probably never be a problem!

 

[SammichLover]

What the exact reason is for the reduction in available capacity above 0 rated miles, I don't think anyone can really say for sure here.

Until someone is brave enough to see if the kWh have been moved to the sub-0 zone?

That is a possibility. We do know that prior that they shipped with “10 miles” in that reserve, as per direct statement to a local EV club here by someone that was a part of the battery dev team until about 48 hrs prior to the day he made the statement (I’d have to dig up his exact name & title).

 

[Vader76]

Mine dropped after 2019.20.4.2

 

[Shopaholic]

My range has dropped to 293 at full charge last few weeks, no change in my driving habits. Looks like they capped it so when the battery does degrade in 3-4 years, it will still show may be 290 at full and you feel good that it is stable!

 

[VangaR]

My SR+ M3 June 26-2019 delivered today charged only 99% and not going further after trying few times removing and attaching the charger . 99% it is only 231miles. This is happening for my car after V10 upgrades such as monster drain and today only I tried 100%, but refused to reach it with 231Miles @99%. This seems to be 234miles for 100% and within 4months 6 miles thats 2.5% degrade of battery is worrying much. Last weekend i drove to Yosemite from Bay area and notice while driving back, it gained 20+ miles due to the downhill regeneration future. Thats quite surprising and I have not noticed how much it drained while uphill, driving towards Yosemite.

Is there any of these uphill/downhill drives cause the degradation of this 99% charge and drop of 2.5%?

 

[Jason_G]

I wonder if there was a bad batch of batteries last September. I'd need to re-read the entire thread to confirm but all of the build dates of the problematic cars was Sept. '18 IIRC. Might be worth everyone with bad degradation stating their build dates.

For another data point, I have a 5/18 build date RWD LR with 26k miles. Charged to 100% yesterday for a road trip and it showed 309 miles. Showed 311 when new. Highest ever was 318 after the 325 mile announcement but it fairly quickly went back to around 310 +/- 2-3 miles. I don't use TeslaFi so this is just from the occasional 100% charge or doing the math from a lower charge level. I don't remember ever seeing/calculating less than 306 miles.

I usually charge to 70-75% daily unless I know I'm going to need more range. I've driven two 4000 mile road trips + the one that I'm on which is just from Denver to Santa Fe. Lots of Supercharging on the road trips but just charging in my garage otherwise (HPWC).

My wife has the same car as me with only 11k miles on it. She took delivery in Sept. '18 so the build date was probably Jul/Aug. As I mentioned, we're on a road trip so I can't compare miles to % on hers right now. I'll check that out when we get back.

FWIW, mine was 9/18 build, and my 9-11% degradation is worse than any of my local friends.