When I originally got started this thread I was specifically for data on the super light batteries such as:
http://www.amazon.com/PERFORMANCE-16-CELL-MOTORCYCLE-BATTERY/dp/B005C5XS2U/ref=sr_sp-atf_title_1_1?ie=UTF8&qid=1392572235&sr=8-1&keywords=ballistic+16+cell
Since it's about $240 shipped, has more cranking amps than the PC680, weighs 10 lbs less, and is physically smaller than the the pc680.