# Car and Driver Battery Article



## clerkp

Any thoughts on this from members here:

https://www.caranddriver.com/news/a35203450/tesla-model-3-battery-capacity-loss-warranty/

Definitely appears they did not charge the car in a manner in which most of us plan to.


----------



## Klaus-rf

Yeah, kinda not worth reading -- they don't understand EVs. Comparing apples to antelope.

I was amused by this line though:

"However, Tesla makes it clear that in the case of a warranty claim, the car won't necessarily get a new battery, but one that at least meets the minimum 70 percent threshold. "

Do they think when their chevy / ford / dodge / toyota / etc. engine blows up at 48,000 miles they will get a NEW one versus a reman unit?


----------



## Bigriver

The estimated full range as the car ages is probably the most popular thread topic.

My thoughts on that specific article: They said they had charged to 90% or more 500 times in 24,000 miles. That means they averaged charging every 48 miles. While that is just an average, it makes me wonder how much the battery ever gets cycled below 50%. The model 3 BMS (battery monitoring system) has shown itself to be sensitive to needing to occasionally be cycled over more than a narrow state of charge.

They also treated their rated range as an absolute. Most of us who watch this for our car see periods of it gaining range as well as losing range. My original range of 310 rated miles has shown as low as 288 miles (7% loss) but it is currently back up to 296 miles (4.5% loss).

I do like that they use Teslafi. It is indeed a data nerd bonanza of info.

But a final thought is that the rated range is really not all that important. There are so many inefficiencies that come into play that depend on driving styles and weather conditions that a 5% or even 10% drop in the car’s rated range impacts very few situations.


----------



## clerkp

As a new owner, I understand the battery balance issue a bit but is there any drawback to multiple short trips versus longer trips as it relates to actual degradation? From a charging cycle perspective it shouldn’t matter should it?
As for the article, they seem to acknowledge they have abused the battery more than most. As for the line from Tesla about some sort of refurb battery, that seems ridiculous to me.


----------



## shareef777

I refuse to click any car and driver links. Everyone I’ve gone to in the past always includes a question insinuating limits of EVs that aren’t standard.


----------



## NR4P

clerkp said:


> As a new owner, I understand the battery balance issue a bit but is there any drawback to multiple short trips versus longer trips as it relates to actual degradation? From a charging cycle perspective it shouldn't matter should it?
> As for the article, they seem to acknowledge they have abused the battery more than most. As for the line from Tesla about some sort of refurb battery, that seems ridiculous to me.


Short trip driving, no issue.
But if you plugging in daily and rarely letting the battery drop below 50%, you may see the top end range lower.

I charge every 5 to 7 days to 90% and let the battery drop to 20% to 30%. Per Tesla's instruction from the senior tech locally with 6 years at Tesla. This brought my range back to within 3% of delivery after 24K miles.
I was also advised to avoid excessive little bump charges (60% to 70% etc) just cause it's free at supermarkets etc. Their advice has worked well for me over a year.


----------



## JWardell

I feel like C&D is a forum newbie that storms on complaining about their lost battery range in their first winter. Except I can't scream loud enough to them that they don't understand its just software and to stop telling lies to the world. Strike 2 this week for them.


----------



## clerkp

NR4P said:


> Short trip driving, no issue.
> But if you plugging in daily and rarely letting the battery drop below 50%, you may see the top end range lower.
> 
> I charge every 5 to 7 days to 90% and let the battery drop to 20% to 30%. Per Tesla's instruction from the senior tech locally with 6 years at Tesla. This brought my range back to within 3% of delivery after 24K miles.
> I was also advised to avoid excessive little bump charges (60% to 70% etc) just cause it's free at supermarkets etc. Their advice has worked well for me over a year.


How does this advice correspond with the manual stating to keep the car plugged in at all times? If I keep going on local trips at 5 to 10 miles and keep my car plugged in as recommended it will stay charged and will get numerous little bump charges as you call them. Should I not do this? Sorry if this is going off topic but I'm genuinely interim best charging habits. Edit - my bump charges are all at home via 14 50 and not via supercharger.


----------



## GDN

clerkp said:


> How does this advice correspond with the manual stating to keep the car plugged in at all times? If I keep going on local trips at 5 to 10 miles and keep my car plugged in as recommended it will stay charged and will get numerous little bump charges as you call them. Should I not do this? Sorry if this is going off topic but I'm genuinely interim best charging habits. Edit - my bump charges are all at home via 14 50 and not via supercharger.


If you ask this question to 20 people, you are likely to get 20 different answers. I don't follow the Tesla rule, but Tesla (as you note) and Elon say plug it in if you aren't driving it. A local club member likes to tell everyone, A plugged in Tesla is a happy Tesla. So you can follow Tesla's advice or do your own thing and your results may vary.

We may not know truly the difference for 10 to 15 years to know if it could have made really long term difference.  There is truly no reason not to follow the advice of the people that built your auto however.


----------



## garsh

clerkp said:


> How does this advice correspond with the manual stating to keep the car plugged in at all times?


The "keep the car plugged in all the time" advice is simply the easiest thing to tell people with the least amount of downsides. But as noted, keeping the battery's state-of-charge (SOC) within a narrow range will confuse the battery management system (BMS), causing it to report less range than what's probably actually available. But it won't hurt the HV battery - unless you charge it to high SOC, like 90%+ - then it will hurt it a *little* bit.

Personally, during this pandemic while I'm mostly WFH, I've kept my car plugged in all the time and set my car to charge to just 50% (lithium batteries generally like to be about half-full for battery health). However, the BMS is getting really confused. The last time I charged to 100%, I saw a range of 302 miles. Now it's down to 290 after a couple of months of this. It's nothing to worry about. Once I start road-tripping again and exercise the SOC range more, I'm sure some of that "lost range" will recover.

And some of that reported "range loss" will be due to natural degradation. After owning a Nissan Leaf that lost over 40% of its range, I'm not going to sweat it.


----------



## FRC

C&D makes clear their intention to mislead and deceive in the sub-headline of the article. "If our car's battery continues to erode at this rate..."

They well know that degradation is not linear, that's why they chose to use the word "If". Why refer to degradation as erosion? Because it's a more inflammatory word, it gives newbies the mental picture of battery liquids sloughing off onto your garage floor.

Their intention is not to inform, but to inflame. This article is worthless, as is Car & Driver. They need to worry about their own degradation!


----------



## garsh

The top comments that people have left on the article do a good job of explaining that most degradation happens in the first year, then degradation slows after that.

It's a shame the author didn't do a little more investigating before writing that article.


----------



## JasonF

At this point when I see a thread headline with "Car & Driver" and "Battery" I start wondering if they've resorted to violence.


----------



## Bigriver

garsh said:


> The "keep the car plugged in all the time" advice is simply the easiest thing to tell people with the least amount of downsides


I agree with this. I think Tesla just wanted to provide a simple method that would keep people from getting into trouble. I have to think of some of my scatterbrain friends who think nothing of running out of gas - Tesla wants to counterbalance this possible behavior. If you look at the context in the manual (screenshot attached below), it is emphasizing:

Plug in if you are not going to be driving it for several weeks.
The battery will have some drain rate while it is just sitting.
Letting it go to 0% is very bad.
Letting it go to 0% is very bad.
The car has self-defense mechanisms to try to keep it from going to 0%, because that is very bad.
The manual never tells what is an optimum charge limit. As Garsh points out, lithium ion batteries like 50%. The model 3 BMS seems to like to see 90% and lower than 50%. My charging behavior is similar to @NR4P's, although I drive less so charging is even less frequent. The advice he got from Tesla Service is consistent with what many have reported from Tesla Service.


----------



## garsh

FRC said:


> C&D makes clear their intention to mislead and deceive in the sub-headline of the article. "If our car's battery continues to erode at this rate..."


_"never attribute to malice that which is adequately explained by stupidity"_
In this case, I think it's just ignorance. EVs are still very new things to most people.


FRC said:


> They well know that degradation is not linear, that's why they chose to use the word "If".


To be fair, that applies to Teslas in particular. The battery degradation on my Nissan Leaf was pretty damn linear. And that's why I'll never own another Nissan.


----------



## SR22pilot

My car was purchased Sept 30, 2018. It originally showed a full charge range of 308. It now has 17,000 miles and shows a full charge range (calculated) of 280. That is a 10% loss from 310 and 9% from 308. The car was initially charged to 70%. After initial rapid degradation I have done a couple of 10% to 100% charges with no effect. Now I generally charge to 90% but only when car will be immediately driven. My other car was bought November 2018. It originally said 310. It now says 302 for a loss of 3% although the rate range was more like 290 till recently. this car has 27,000 miles on it. Tasted range numbers are from Stats since I don’t fully charge.


----------



## clerkp

Bigriver said:


> I agree with this. I think Tesla just wanted to provide a simple method that would keep people from getting into trouble. I have to think of some of my scatterbrain friends who think nothing of running out of gas - Tesla wants to counterbalance this possible behavior. If you look at the context in the manual (screenshot attached below), it is emphasizing:
> 
> Plug in if you are not going to be driving it for several weeks.
> The battery will have some drain rate while it is just sitting.
> Letting it go to 0% is very bad.
> Letting it go to 0% is very bad.
> The car has self-defense mechanisms to try to keep it from going to 0%, because that is very bad.
> The manual never tells what is an optimum charge limit. As Garsh points out, lithium ion batteries like 50%. The model 3 BMS seems to like to see 90% and lower than 50%. My charging behavior is similar to @NR4P's, although I drive less so charging is even less frequent. The advice he got from Tesla Service is consistent with what many have reported from Tesla Service.
> View attachment 36697


it says in all caps to leave the car plugged in at all times. It does say particularly if you not driving but I don't interpret that to mean _only_ if you are not driving. I've heard these anecdotal reports where people say that the always charging rule is some sort of marketing ploy by Tesla for consumers. It would be nice if there was something more definitive. I mean, it's just as easy for me to not leave the car plugged in all the time as it is to leave it plugged in. My car is a performance model so I generally prefer to keep it charged higher (i.e. 80 percent plus) to receive the benefits of the car that I purchased. My guess is luck is the biggest factor in battery degradation versus the differences between 70 to 80 or leaving plugged in versus not. Having owned a lot of cell phones over the years, I can say that some have great batteries and some just don't.


----------



## clerkp

SR22pilot said:


> My car was purchased Sept 30, 2018. It originally showed a full charge range of 308. It now has 17,000 miles and shows a full charge range (calculated) of 280. That is a 10% loss from 310 and 9% from 308. The car was initially charged to 70%. After initial rapid degradation I have done a couple of 10% to 100% charges with no effect. Now I generally charge to 90% but only when car will be immediately driven. My other car was bought November 2018. It originally said 310. It now says 302 for a loss of 3% although the rate range was more like 290 till recently. this car has 27,000 miles on it. Tasted range numbers are from Stats since I don't fully charge.


This seems to support the "luck" theory. 10% on a car that is now nearing 2.5 years old doesn't seem terrible to me although the miles are very low.


----------



## garsh

clerkp said:


> It would be nice if there was something more definitive.


We can get into all of the nuances on this site (and we have done exactly that on many occasions). Feel free to search around for previous discussions on charging strategies. But Tesla's recommendation is a good, general one to abide.


----------



## SR22pilot

clerkp said:


> This seems to support the "luck" theory. 10% on a car that is now nearing 2.5 years old doesn't seem terrible to me although the miles are very low.


One piece of info I should add. The second car is RWD with Aero wheels. The first is AWD with 19" rims. The newer car has more miles because it is the trip car. It gets probably 50 miles more. Stats says estimated range of 208 vs. 310. Some of that is the difference in driving styles. Still, the RWD is our trip car. The greater range makes a huge difference. The EPA range for the RWD car was later updated to 325. Based on that, battery degradation is 8%.


----------



## NR4P

clerkp said:


> How does this advice correspond with the manual stating to keep the car plugged in at all times? If I keep going on local trips at 5 to 10 miles and keep my car plugged in as recommended it will stay charged and will get numerous little bump charges as you call them. Should I not do this? Sorry if this is going off topic but I'm genuinely interim best charging habits. Edit - my bump charges are all at home via 14 50 and not via supercharger.


Confusing isn't it? I was watching my 100% range drop and filled out a service ticket. The s/w remote tech called me and discussed my charging habits as he had remote connected the car. He said to stop charging in piece meal every chance I get even if its free. Try to go below 50% periodically and back to 90% in one charge. Once in while is ok, not all the time.

I asked him about the manual and other Elon tweets and he responded with something like, hey I have been here for 6 years and trust me, the BMS needs to have some ups and downs.

Sure enough my 100% range slowly returned to within 2% of delivery at 24K miles. I now have 36K and less than 3% degradation. So it has been good for me. But as they say YMMV


----------



## Klaus-rf

Founds this video from C&D. Does not appear to be negative.

https://www.caranddriver.com/news/a34115854/tesla-model-s-plaid-1100-hp-pre-order/


----------

