Official Galaxy S3 Extended Battery Almost Here, Stays Thin I can surely use a few extra hours my SIII, but I would never by the typical extended battery. They take your beautifully svelte smartphone and turn it into a brick. Well according to this, Samsung will start offering a 3000 mah extended battery kit that still manages to keep the phone thin. If this is true, I am first in line. Though I am skeptical - Why no word of this on the Samsung site? Why Amazon Germany? Will this work on US version of S3?