I use this one with a 80 watt panel
http://www.amazon.com/gp/aw/d/B00L37KZI6/ref=mp_s_a_1_2?qid=1458257920&sr=8-2&pi=SY200_QL40&keywords=solar+charge+controller&dpPl=1&dpID=51F-n%2BsohrL&ref=plSrch