Anyone have any experience with Sears brand Battery maintainer? I have one and in the last month have had to refill the battery twice. It seems to be charging, when in fact the battery is dead. New battery in May so that is not the problem. I'm inclined to think that I have a faulty charger and it is giving too much of a charge and boiling the water out of the battery. Any ideas before I head back to Sears?