I think I need a battery tender but am unsure what to get or should I get something different? I want to use it for two purposes. I have a few regular old style large battery chargers that I use to charge up a dead battery. I want to use the tender to top off a battery after charging so I don't over charge them with my old style chargers and want to keep batteries up in the winter, say every few weeks. I do not want batteries hooked up to a tender 24/7 because of fire danger and I can't have cords everywhere all of the time. I have only regular lead acid type batteries, mostly ones that I add water too but a few maintaince free. I am mostly 12 volt but do have a couple of 24 volt systems. 6 volt would be nice too but is not critical. My batteries range from 12 volt 360 CCA to two 12 volt 1300 CCA in series (about 100lbs each) with mostly 12 volt 850 CCA batteries making up the rest. Some batteries I can bring inside the shop for the winter and some I need to take the tender to in the outside cold. Any recommendations? Thanks!!