As a new owner of an RS a year ago I went out and bought a charger to "keep the battery up" as many suggested. Last winter I used the charger every week or so to check my battery's charge. Guess what? Over the course of threee months it never lost its charge, I never used the charger at all. My guess is that, if your battery keeps running down over short periods of time, you have an issue with shorts or something plugged in that uses juice when the machine is not in use. My further guess is that many who have the problem have installed "mods" that were poorly designed or incorrectly installed. About the only item drawing power in the off position is the clock. When you stop and think how little power a clock requires (think electric watch that runs 3 years on a button battery) and it us obvious the large battery in a vehicle will hardly be affected. Bottom line, unless you plan to store your Spyder for long periods of time, save your money. It should NEVER be necessary to plug in charger on a regular basis unless there is a problem with the machine or a bad battery. Just as an aside, I purchased my 2009 RS used (had only 600 miles on the clock) and it still has the original battery installed. I don't know what the mean life is for a sealed battery, but I must be in the upper range.