How is charging 100% really hurt the battery?

[sthabouthenry]

I just got notified by Tesla delivery team that my M3SR+ is arriving by the end of this month, and I am also booking their authorized tech to install the home charger at my office. I live in an apartment where I cannot install the charger, so I can only install it at work place.

I have read a lot of articles and youtube regarding the M3SR+ real range is about 270km at a 80% charge. Most of these articles and even Tesla suggest that we don't charge it at 100%, but my daily commute is about 120km to work. Ever since I ordered the car, I have been paying more attention to nearby or my regular spots where it has charging station, but most of the time these spots are occupied. That makes me worry if I don't go to office for more than 2 days and I may have a range problem.

Is it okay charge it to 100% every Friday, especially long weekend? I am planning to put lots of miles on the car, and tend to keep it for at least 6 years. I'd like to minimize or prevent battery degradation. Any advice would be appreciated. Thank you.

 

[Puddles]

You can charge to 100%, just use it immediately. Same thing at the low end. Don’t let the battery stay at either extreme for long.

Congrats and welcome!

 

[Ken's M3]

This video explains how battery degradation happens, probably in too much detail.

 

[dhrivnak]

I would try to refrain from range charging every week. When you charge that last 10% the battery cathode actually expands causing some minor physical breakdown. Similarly below 10% there is some shrinkage. So the sweet spot is between 10 and 90%.

 

[sthabouthenry]

I would try to refrain from range charging every week. When you charge that last 10% the battery cathode actually expands causing some minor physical breakdown. Similarly below 10% there is some shrinkage. So the sweet spot is between 10 and 90%.

So I should set limit at 90% daily charge?

 

[sthabouthenry]

You can charge to 100%, just use it immediately. Same thing at the low end. Don’t let the battery stay at either extreme for long.

Congrats and welcome!

Thank you. I am excited.

 

[Puddles]

I think the principle is: if you really need it, use it. That’s what it’s there for. If you don’t really need it, just go to 90%.

 

[dhrivnak]

So I should set limit at 90% daily charge?

Yes that should be fine. I know on the Roadster below 82% the battery BMS is unable to balance. So one is walking the line between balancing and cathode swelling. My daily charge is set to 90%. Confirmed by two rangers and Elon in tweets.

 

[sthabouthenry]

Thank you all. I can't wait

 

[Kevy Baby]

I have read a lot of articles and youtube regarding the M3SR+ real range is about 270km at a 80% charge. Most of these articles and even Tesla suggest that we don't charge it at 100%, but my daily commute is about 120km to work.

I am not sure if you mean 120km one-way (240km round trip) or 120 km round trip. If the former, you may have a tough time making that on a single charge depending on all the other factors (weather, driving style & speeds, etc.).It MAY be okay, but I would definitely be looking at charging to at least 90%.

 

[ewoodrick]

A battery that sits at 100% for a long time can cause outgassing and cell expansion. A long time is measured in many months.
This is something that happens to cellphones and laptops as well, especially laptops that stay plugged in. The batteries will swell and may bust the case open, at least deform it. Many of the laptop and cellphone manufacturers are providing profiles that minimize this from occurring, by limiting the max battery charge.
If you only have a 120km commute, you should easily be able to set the max to 90% and stay happy.
It is okay to charge to 100% when you need to, like going on a trip.

If you leave the max setting at 100%, after a few charging sessions, you will get the message that you might want to limit to something lower.