I would not buy this charger.  I used it for maintaining my boat batteries during winter.  When I initially plug it in and connect it to the battery everything seems fine.  However, later when checked it the red LED is flashing and my battery is completely dead.  At $100 minimum for a marine/deep cycle battery this gets really expensive fast, especially when I need to rely on my battery while on the water.  This has happened multiple times.  There is not indication on-line or in the manual what could cause this behavior.  Also, Schumacher claims it this charger is okay to leave connected while not charging.  This is clearly not true since it drained my large battery to 0 multiple times.  When not powered this charger will drain your battery.  Beware of using this charger.  It is better to just charge you battery and disconnect it than risk drawing it down to 0.