The Pro-Fill Battery Watering System is specifically designed for use with golf cars. The Pro-Fill on-board battery watering system works by replacing the battery's existing vent caps with valves that are interconnected with tubing, allowing the user to fill all cells of the battery from a single remote location. Each valve independently shuts off water flow to the cell when the proper electrolyte level is reached, allowing the batteries to be filled perfectly every time without having to look at the batteries.