Theory: People who baby their batteries experience more "degradation"

[dmurphy]

Imagine if our ICE vehicles' fuel gauges read in miles left. People would be going nuts

They do. Every car I've had in the last 15+ years has had a "xxx miles to empty" indicator. I haven't looked at a gas gauge in decades; they're flat-out stupid. Just like battery % - that's not how highway signs are measured.

"Ocean City is 70 miles away; can I get there?" Using a percentage gauge - whether it's gas or electric - is an anachronism from a time when we didn't have anything better than a tank float and a needle. We do, we have for decades, and it's time to put that BS out to pasture.

 

[camalaio]

They do. Every car I've had in the last 15+ years has had a "xxx miles to empty" indicator. I haven't looked at a gas gauge in decades; they're flat-out stupid. Just like battery % - that's not how highway signs are measured.

"Ocean City is 70 miles away; can I get there?" Using a percentage gauge - whether it's gas or electric - is an anachronism from a time when we didn't have anything better than a tank float and a needle. We do, we have for decades, and it's time to put that BS out to pasture.

I think their point was if ICE vehicle displayed rated range, like Tesla does. I think the ICE vehicles that display range are all estimates based on driving for some previous amount of distance covered. A measurement I like, but also know is bunk because mountains exist. (and reading, oh no, only 50km left! at the top of a hill doesn't mean I won't make it 60km down the hill to the next down, just like rated range!). As an also human being, I also do think distance is more relevant to our understanding than some percentage.

To @chdavis 's point, I don't agree. A large part of the reason the rated miles display is so problem-causing for folks is because it degrades over time, because it's a battery. An ICE vehicle wouldn't have the rated range decline over time because the gas tank stays effectively the same size the entire time. I'm very purposely not discussing efficiency loss over life, because we're talking about rated range displays.

Oh no... did this thread turn into a percent vs. distance one too?!

 

[Dolemite]

Why would anyone wanna go to Ocean City?

 

[dmurphy]

Why would anyone wanna go to Ocean City?

I meant the good one......

 

[chdavis]

They do. Every car I've had in the last 15+ years has had a "xxx miles to empty" indicator. I haven't looked at a gas gauge in decades; they're flat-out stupid. Just like battery % - that's not how highway signs are measured.

"Ocean City is 70 miles away; can I get there?" Using a percentage gauge - whether it's gas or electric - is an anachronism from a time when we didn't have anything better than a tank float and a needle. We do, we have for decades, and it's time to put that BS out to pasture.

Range changes on how you drive - gas, diesel, or electric. It's only relevant how much energy you have remaining. If you need more, fill up.

 

[acarney]

I “take care” of my battery. Only have about seven supercharger sessions on it and everything else is level 2 (240v 32amp). I have approx 7,500 miles on a 2019 SR+ and normally charge to 75% and am not below 60% by the time I get back home.

Teslafi reports a 0.12 mile range loss or about 0.05%. My lowest range vs highest is 2 miles or 0.85% and that was back around 5,100 miles.

 

[AdamVIP]

I think you are right in that what is good for the battery doesn't correlate with good readouts. If it is a subject one worries about I would make a general rule to charge to the recommended 80-90% on the regular and once or twice a year do a battery cycle to let the system re-calibrate and check on if you are actually losing capacity.

 

[Dolemite]

I think you are right in that what is good for the battery doesn't correlate with good readouts.

Good way of summing it up.

 

[mrgoogle]

It’s only about battery lottery. Most people win and a few don’t (like me).

 

[Rocky_H]

I think you are right in that what is good for the battery doesn't correlate with good readouts.

Yes, this is absolutely the thing. And so you see people accidentally going against their best interests. They look at the number displays and harass a Tesla sales or service person about what they can do to make the number look better. The employee answers that question (which isn't really the best question to be asking), and then the car owners keep talking about "Tesla's recommendation". Well, they helped you with making that number look better, but not really what is best for the battery's health, because you didn't ask about that.

 

[Dolemite]

FWIW, my range @ 100% suddenly "went down" by some number a few weeks ago... but the thing is, I'm able to beat the Trip estimate by 4 - 5% every single time I go on a long drive. This is cruising 75 - 80 mph with a few hard accelerations in there for good measure.

 

[mrbulk]

For me it's set and forget (90%), always plugged in when I get home, etc., and never had an issue. Then again I'm leasing (expires in about 8 mos.) and getting another Tesla anyway, so...maybe I should up it to 100% these last 8 months?

 

[BLW2]

I perfectly understand and can relate to how obsessing over the decimal point can be.
But I've learned over the years to generally dislike digital almost anything.... gauges and measurement anyway. Too easy to loose sight of the real target.
Digital tire pressure gauge is an example. No need to get down to the 10th or 100th of a psig but when the data is presented it'll drive me nuts if they don't all match.
Fuel gauges... I've been driving almost 38 years never being able to tell exactly even to the 1/16 of a tank, how much I have left in the tank if solely based on looking at the gas gauge. In my current truck which doesn't get great mileage, that could be 30 miles or more range...and it works ok

 

[Dolemite]

I perfectly understand and can relate to how obsessing over the decimal point can be.
But I've learned over the years to generally dislike digital almost anything.... gauges and measurement anyway. Too easy to loose sight of the real target.
Digital tire pressure gauge is an example. No need to get down to the 10th or 100th of a psig but when the data is presented it'll drive me nuts if they don't all match.
Fuel gauges... I've been driving almost 38 years never being able to tell exactly even to the 1/16 of a tank, how much I have left in the tank if solely based on looking at the gas gauge. In my current truck which doesn't get great mileage, that could be 30 miles or more range...and it works ok

The newer 3 series they gave me when I took my BMW in for its 40th Takata recall displayed tire pressure down to the tenth on the screen... makes zero sense.

 

[CertLive]

There is a BMS for a reason so I charge mine to requirements. The car has got me from A to B just fine so far.... just the quality :S

 

[David99]

I've had my Tesla for over 6 years and close to 300 k miles. I've learned a few things over the years. The most important thing I have learned is that as soon as someone is interested in EVs they automatically become a battery expert. And once they own a Tesla they know for a fact that they are right.

I love when people who just got their car 8 months ago and driven 7 k miles discuss degradation.

 

[CertLive]

I've had my Tesla for over 6 years and close to 300 k miles. I've learned a few things over the years. The most important thing I have learned is that as soon as someone is interested in EVs they automatically become a battery expert. And once they own a Tesla they know for a fact that they are right.

I love when people who just got their car 8 months ago and driven 7 k miles discuss degradation.

People who think every battery pack is the same as theirs.... clearly this is not the case (6 years is ancient battery tech). Some people have quite harsh degradation some not. They also age over time even when not used. Its the way its all advertised is more of the scam. Cars should show battery degradation and should be advertised after the first year will do less miles than the first. Then you know what you are buying. So add on with an ICE how many miles do you lose on the first year? Second and third on average. It is not very clear on the website how even the weather will effect your car in the climate you intend to drive it in. Things could be so much clearer to the end user but $$$ prevails of course.

 

[David99]

People who think every battery pack is the same as theirs.... clearly this is not the case (6 years is ancient battery tech). Some people have quite harsh degradation some not. They also age over time even when not used. Its the way its all advertised is more of the scam. Cars should show battery degradation and should be advertised after the first year will do less miles than the first. Then you know what you are buying.

I never claimed the 85 packs as the same as the M3 but they are not as different in terms of chemistry as you might think. When the Model S came out Tesla claimed battery technology gets better by 5-8% every year. That claim/prediction turned out to be wrong. The increase in capacity in the 100 packs is mainly due to fitting 16% more cells into the pack and improving the cooling. The M3 battery has the same energy density as a 100 pack. If you think your M3 battery will not show the same symptoms of degradation a few years from now you are optimistic at best. M3 batteries are the same chemistry as the 100 packs used for the S/X just in a different form factor.

 

[camalaio]

I never claimed the 85 packs as the same as the M3 but they are not as different in terms of chemistry as you might think. When the Model S came out Tesla claimed battery technology gets better by 5-8% every year. That claim/prediction turned out to be wrong. The increase in capacity in the 100 packs is mainly due to fitting 16% more cells into the pack and improving the cooling. The M3 battery has the same energy density as a 100 pack. If you think your M3 battery will not show the same symptoms of degradation a few years from now you are optimistic at best. M3 batteries are the same chemistry as the 100 packs used for the S/X just in a different form factor.

There are more differences in an S/X vs. a 3/Y pack than just the cell size.

Allowed cell voltages are different (much wider on the 3). Thermal management and thresholds are different. The way the range is reported is different. The BMS is different. The control software is different.

There are few valid comparisons between Tesla's older packs and the current ones. Some general lessons are still applicable (e.g. don't always charge to 100%). Their degradations may end up being similar in the end, but it's likely their differences will make one "worse" than the other.

 

[ran349]

There are more differences in an S/X vs. a 3/Y pack than just the cell size.

Allowed cell voltages are different (much wider on the 3).
The way the range is reported is different.
The BMS is different.
The control software is different.

There are few valid comparisons between Tesla's older packs and the current ones. Some general lessons are still applicable (e.g. don't always charge to 100%). Their degradations may end up being similar in the end, but it's likely their differences will make one "worse" than the other.

Could you provide more detail on what the differences are? Source references also.

Thanks.