I have read the manual and the FAQ. The manual doesn't really specify values and only says to charge to "the level of charging you want". The FAQ is a little more clear in that it says to charge "within the 'Daily' range bracket, up to approximately 90%". That still doesn't clarify how 50% is different from 90%. As E90alex stated, if 90% is the preferred value, why not just make everyone charge to 90% and not give people an option?Have you read the manual for your car? What did it say?
General recommendation from Tesla or Elon, charge to 80 or 90% unless you need to go on a trip, which in that case you can charge to 100%.
Tesla built the battery to take a beating.
ALL of the studies and recommendations that you hear are from studies about other batteries, not the specific formulations that Tesla uses. The formulation makes a huge difference.
For a newer car, your batteries are designed to last over 300,000 miles.
Enjoy the car, charge as fits your lifestyle and needs. One of the few statements from Tesla, a plugged in car is a happy car.
By charging your car to only 50% you are effectively throwing half of your range away. You bought it, you paid for it, so use it!!!
Your car will lose a percentage over the first year or so, this is expected and completely normal. This occurs no matter how you charge it.
Ask the folks who recommend 50% how much range are they expecting to add to the battery. Is it a year? a month? or a mile. No one really knows.
I've seen Elon's suggestion to charge to 80-90%. I've also seen him saying that Jeff Dahn's suggestion of 70% being better than 80-90% was correct ( ), but he still says 80% is preferable to him for convenience.
If my daily needs warranted me needing 80% of a charge to comfortably get me through a day, I'd charge it to 80%. But 50% is more than enough to get me through a day of typical driving. On a day when I'm going to take a long trip, I'll charge it up to 100% without a second thought. But, assuming there is battery longevity gains at lower SoCs (however small they might be), why charge above 50% on a daily basis when my total daily mileage is a small fraction of what that 50% provides?
As for how much range one can expect to gain from the battery by keeping it at 50% vs 80-90%? That's the million dollar question. Tesla promises no more than 30% degradation over its warranty period. Honestly, that sounds like quite a lot. If keeping it at 50% is only going to make a 1% difference over 10 years, perhaps it's not worth even talking about it. But if it keeps the capacity at 5-10+% by the time the warranty expires, I put a decent amount of value in that. Especially for those of us that plan on keeping the car past its warranty period.
I appreciate the discussion from everyone - those who are in the 90% camp and those who are in the 50% camp. I think everyone here agrees to charge to a level that meets your daily needs and to never sacrifice convenience in an effort to preserve battery capacity. But daily needs and convenience are two variables that can be drastically different from one person to the next. Hence I fully agree with you - "Enjoy the car, charge as fits your lifestyle and needs."