In the FAQ Tech Talk thread an interesting point came up with someone indicating that they choose to charge their Tesla below the full 40 amp charge rate possible on their home outlet, instead choosing to throttle the charging speed to 15 amps since they can still get the charge level they need and hope or expect that this will have a positive affect on long term performance of the battery. I think that this is a subject worthy of further discussion in order to better understand two issues; 1. Does voluntary reduction of charge rate in home charging scenarios prolong battery life? 2. Does capping charge to a below max range value prolong battery life? This is what I believe we know about this at this time. When time permits I will start quoting and linking sources. 1. Elon Musk when pressed on the question of what charge level home owners should charge to for daily driving in order to get maximum longterm life of the battery is quoted as saying "around 80%". I believe this was something he posted to Twitter. 2. Tesla have published information that indicates that owners that charge frequently at high charge rates at super charger stations can expect a small amount of battery wear to result. Super charging though has no impact on warranty which has a maximum allowable battery reduction of something like 1-2% per year. 3. Initial survey information from Model 3 owners does not appear to show any correlation between battery degradation and type of charging done. http://www.pluginamerica.org/surveys/batteries/model-s/faq.php 4. Private Model S/X rental/taxi operator in the Southern California area that rents a large fleet of Model S/X cars charge exclusively on super chargers (taking advantage of the bundled "free" supercharger access) and some of their vehicles have over 100,000 miles on them with no observed extra wear on battery life. http://www.greencarreports.com/news...0k-and-300k-miles-still-humming-along-happily It is worth noting that the operator did have one Model S that had its battery completely replaced under warranty during the unlimited mile 8 year battery warranty, it would no longer take a charge. It's hard to say what would happen if a regular owner ran into this problem after 8 years since their battery was basically dead and would have cost $20,000 to replace out of pocket.