We've used optima batteries on our endurance race cars for a few years now and use their charger to maintain and occasionally bring one back to life. If you run an Otima batteries should you should use one of Optima's computer controlled charger to maintain the battery. Here's the least expensive (and the one we use) charger:
http://www.jegs.com/i/Optima-Batteri...waAiQmEALw_wcB. It can perform magic onn these AGM batteries. There is a more full-featured model but this $90 version has proven adequate with our batteries.