I plan to own my Model S for as long as possible. I do NOT plan on replacing the battery, and after it loses it's long distance capabilities, I plan to make it our "around town" car, and direct any battery replacement funds to the latest and greatest thing for our second vehicle. As such, I am keenly interested in understanding exactly how the Model S battery works so I can extend its usable life as long as possible. Here is what I know for sure, from the owners manual: I should keep the car plugged in whenever possible Charging to maximum is worse for the battery than charging to 90%. So this brings up a million questions for me: WHY do I need to keep the car plugged in all the time? Are there battery health benefits to keeping it as fully charged as possible, or is this just to prevent people from "Brodering" it and accidentally draining the battery? Does the battery management system behave differently if plugged in, vs. not plugged in? Is battery longevity affected by the state of charge while not in use? If so, do I understand that 90% is better than 100% when sitting in my garage? If 90% is better than 100%, is 80% even better than 90%? What about 5% or less, is that harmful? . What actually causes battery degradation? Is it the charging or the discharging? Does the SPEED of charging or discharging affect it? Is there an optimum charging amperage for battery health if the time involved was not a concern? I've heard that Superchargers are bad for battery life, but then I've also heard the opposite. Does anyone know for sure? Does the battery degrade based on time, or usage? Both? Does the length of a charge matter? Is it better for the battery to have one giant charge from 10% to 90%, or multiple tiny charges keeping it "topped off"? Does ambient temperature matter, considering that the battery has it's own internal temperature control mechanisms? Is it worse for the battery if I leave my car parked outside in the winter, or should I bring it in the garage? Much of my driving is either long trips or very small around town trips, so I have the ability to leave the car unplugged for up to a week at a time, and would consider making small changes to my charging habits if it has the possibility to affect long term battery health. Sorry for all of the questions... I have heard various conflicting reports while surfing around these forums and elsewhere, and I'm curious if anyone knows for sure the answers to some of these. Thanks for your help!!