Correct topping up of lead acid batteries is essential - too much water and the electrolyte will overflow, too little and the battery will quickly fail. To ensure that each cell is topped automatically to the correct level IBCS offer a centralised filling system called BFS.
BFS is a float system, the float in each cell operates a valve that shuts off the supply of water to the cell as the float rises. The system is universal, and compatible with that of many of other battery manufacturers. There is a level indicator in each cell plug, which indicates the electrolyte level, and the top flips open to allow access for a hydrometer.