The Model S has two charge modes: standard and max range. Standard is the default and charges to 90% of capacity (approximately 240 miles in rated range). Max Range goes to 100%, but is discouraged for battery health reasons and has to be set manually each time you charge. It looks like Tesla is doing things similar to the Volt, but gives you the option to override.
It always seemed to me that the Model S's two settings might be better described as "pushing it" and "really pushing it".
Chevy's maximum state of charge is 80%. The Model S's 90% is pretty surprisingly high, but of course the Model S battery chemistry (Lithium Nickel) is different from the lower-charge one in the Volt (Lithium ion Phosphate).
