So far, I have been happy with the stock battery on my Sportster Forty-Eight. The bike was bought new in August this year. However, as I have a satellite tracker on the bike, this uses up some of the battery. It is not a problem as long as I ride at least every other week. If I know I will not be using the bike for longer periods of time, I hook the battery up to a charging station made for motorcycle batteries. This monitors the battery status and charges as necessary.