My spouse has a German vehicle with a battery the size of a dollhouse that costs at least $165 to replace. Since this is her baby, and we live in the Northeast, it comes off the road from November until May. Certainly, you shouldn't let any car just sit for that length of time. But apparently this thing is still ticking while parked for the winter, so the battery needs constant attention. For the first time, I've come across an incredibly simple,  reliable charger that is affordable and requires minimal human interference — well, honestly — it's just plain perfect.
 
Battery Power Product's Xtreme Charge has cutting-edge technology that monitors your battery's condition while making sure it gets the perfect charge, tells you (by idiot lights, admittedly) what it's doing and does it all unobtrusively, in a package about the size of a carton of cigarettes. A unique charge algorithm built into Xtreme Charge coupled with advanced battery-evaluation capabilities, eliminates the need for users to identify battery type or chemistry, to select or set any specific charge criteria prior to charging, or worry about charging in an improper or potentially unsafe manner. You can't ask for more than that. With an MSRP of only $99.95, I suggest you get it and use it on any boat batteries you have — no matter what kind. Battery Power Products, 888-287-9314; www.xcmarine.com.