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Charging level at 80% & Long Roadtrip

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Curious, I have set my charge limit to 80%, but will be leaving for a long road trip this weekend in my new model Y. It would be nice to charge to 100%, so I can reach my final destination - vs. 80% which will have a stop about half way there...

Why don't owners charge to 100%? I've read that 100% can damage the battery capacity? I apologize if this is already posted, just could not find an answer about this?

Thanks -
 
It's not so much "can damage", but rather that frequent charging to 100% will decrease the battery capacity.

The key is frequent, or really prolonged. If charging to 100% will help you on your trip, don't hesitate to do it. Just do it in a smart way--charge to 90%, and then raise to 100% just before your trip starts so that you leave shortly after it finishes charging.
 
As mentioned, charging to 100% is very slightly more stressful for the battery. Try to minimize the time the battery stays at this level, but don’t worry too much about it. Don’t leave it there all day if you can avoid it.

Charging to full also reduces regen, as there’s nowhere for the energy to go. This will reduce efficiency, but only a little. I find it more annoying as you have to alter your braking habits to compensate.

See also this thread: Battery Degradation Scientifically Explained
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Also keep in mind you are never going to get 316 miles out of a 100% full battery. AC, speed, load weight, wind, rain, elevation changes, etc. are all going to impact your range. All of that deducts from your range, as you drive. Even if you are travelling 280 miles away, even on a 100% battery, you will likely want to charge before getting to your destination, even if it makes it on a single charge. You will want some local driving capacity and also range anxiety will creep in, especially if you havent lived it yet and learned the car, so you will likely want to charge with 20%ish left on the battery. I know some people are comfortable with 10% or less even left when they get to their destination. I dont think I'll be that comfortable for a while. I'd like to know I have 25%ish available just in case.
 
80/20 rule. Try to stay between 80% and 20%. Above 80% is OK, but discharge soon (despite there being some apparent magic in cell re-balancing at 90% and holding there for 24hrs or so - do so every few months). Try very hard to not go considerably below 20%.
 
There was a very large discussion on Reddit regarding this, and essentially it was suggested to stay as close to the 50th percentile of range as possible. Obviously, we all need *some* range, but the suggestion was that if you know you use 20% of your SOC/Range daily, you should charge to 60% and then it would get charged when you get home at 40%, keeping the "median" at 50% SOC. I only drive around 30 miles a day, so I'm planning to try to use 70% max SOC to help with longevity.

Now, there's also the caviat of a law of diminishing returns where the "stress" placed on the battery between 50 to 60% SOC is significantly (exponentially) lower than 60 to 70, then even further comparing 70 to 80, etc.

There are lots, lots, lots of Teslas where the owners have not gone to this obsessive-level type of energy management and they continue to work. I believe I was an Insta Story from Tesla saying that after 200,000 miles, the fleet average is 90% original capacity. That's outstanding. The typical capacity of my ICE vehicles at 200,000 is 0%, because they've almost always had a massive part failure that resulted in a new purchase instead of repair.

TLDR; Your plan of keeping it in the zone between 80 and 20 is fine. Charge it often but don't obsess. If you believe you'll need the extra energy from 80 to 100%, then charge it to 100%, but don't let it linger at 100 - start driving as soon as practical once reaching it.

Regenerative braking won't work above, what, 95% anyway? So be prepared for use of the friction braking.