Daily charging/topping up the battery (even only to 80%) could be very bad

[yavore]

@KD4MNI

You might want to check this too:
Tesla battery degradation at less than 10% after over 160,000 miles, according to latest data

 

[KD4MNI]

Thanks, I'd forgotten about the April 2018 article in electrek and its mention of charging methods. The data confirms how consistently well Tesla battery packs maintain their capacity as they age, and how superior Tesla+Panasonic battery technology and expertise is. I wish I could buy a Tesla battery for my cellphone.
Another key take-away:
"Jeff Dahn, a renowned battery researcher and the leader of Tesla’s research partnership through his battery-research group at Dalhousie University, said that he recommends charging to only 70% daily in order to extend battery life."
And mentioned in the footnotes from the earlier survey spreadsheet:
"Keeping the battery (pack) at 100% or 0% for more than 2 hours is not good for the battery (pack) ... near full discharge is bad for the battery (pack)"
As for the 100% warning, thus the Tesla recommendation to only charge to a full 100% immediately before a long trip or in an emergency situation (when energy stored in the battery will be used immediately).

 

[walla2]

I have some long term Signature P85 data to share.

At 16,000 miles and nearly 6 years, I have only lost a few miles with a 90% charge daily. In 2010, it was 235. In 2016, it was 232. Today, it is 231.

That is minimal loss of range with daily topping of at 90% (vampire plus short commute losses). So the 90% to me doesn't seem as harmful as putting on 10x miles which is likely stressing the pack more by getting to the low end percentages so often.

 

[David99]

At 16,000 miles and nearly 6 years,

16k miles in 6 years so very little driving. Or is it 160k miles?

Just another data point: 181k miles in 4.5 years. 11.5% degradation. 60% supercharging.

 

[walla2]

16k miles in 6 years so very little driving. Or is it 160k miles?/QUOTE]

My commute is 3 mile, and I therefore have various ways I can get to and from work. The post however is about topping off above 80% not miles driven and I can't see that as being overly harmful based on my experience vs. large swings or getting close to the edges.

 

[AmpedRealtor]

I think y’all are too obsessed over the battery. How many decades do you plan to drive this car? Do you realize that tens of thousands of Model S owners have not lost significant range no matter how the car was charged (many of us charging to 90% every night, and 100% for trips)?

Chill out and enjoy driving the car. Or worry about possibility having a percent or two less range in a 310 mile car after many years. Your choice.

I suppose it depends on what you consider "significant". I've lost 20 miles of capacity 5 years after new, or 7.5%. Is that significant?

 

[TexasEV]

I suppose it depends on what you consider "significant". I've lost 20 miles of capacity 5 years after new, or 7.5%. Is that significant?

In a Leaf, yes, a 20 mile range loss would make it unusable. In a Tesla, no, it doesn’t affect the long distance driving experience at all if you lose 20 miles vs. someone who obsesses over the battery and loses 15 miles.

 

[MtHamilton]

I may be off base here, but arguing theoretical battery life may not be important. I have a 85 battery with 60k miles. A year or two ago, the battery had a problem, had to be pulled, and spent close to a month for a rebuild (apparently contracted out for remote repair). Now, the car is in for a second time for another 3-4 week rebuild (Service says it will get a new battery, but I doubt Tesla will give one to me). My fear is that since the battery is lasting only a few years before failure requiring battery rebuild, I need to dump it before I reach the warranty's conclusion at 8 years. Not having the car for a couple of months saves on charge cycles, but I'd rather have my car working reliably. Range reduction has not been noticeable, so I am not sure charging every time I am at home makes much difference.

By the way, the first time, a warning message turned on and I was able to go to the local service center. This time, there was no advance notice. The car just decided to indicate service required as it shut down after being parked for several hours in a public garage (dead - would not go into tow mode; yes, Tesla changed the 12 volt 8 months ago).

With this track record, the car will not make it to 90k, though there might be plenty of life theoretically left on the battery.

For anyone who cares, Tesla replaced my battery with a new one (damaged a coolant fitting on installation, so it took two trips to service - the first over two weeks and the second a few days for a coolant leak). With 65k miles, I now have an early (VIN 00020XX) 2012 Model S 90 with more range than new. By the way, over the first 65k miles, the battery lost less than 5% of capacity (charge topped off to 90% after each daily use; supercharged rarely) based on range readout (admittedly inaccurate - I note that some software updates also appear to change the range algorithm too, both up and down) and my actual is substantially below estimated (mountain driving).

Good to go until the rest of the car falls apart, though changing tires gets tedious (every 15k miles). I won't worry about battery life - just battery failure. Hopefully they make them better 6 years of practice.