Monitoring solution for use in charging stations with lead-acid batteries. The product uses a green signal light to indicate which battery from the pool is ready for use and can be used next in the industrial truck. This solution thus becomes an unmistakable guide to the right battery for the forklift truck, reach truck or order picker - even for employees from different language areas. The monitoring system ensures that the battery pool is used evenly and that cool-down times are observed. This protects your investment by ensuring that each battery reaches its maximum service life. In addition, damage to PzS batteries due to sulfation and stratification is significantly reduced by avoiding false discharges as well as charge interruptions. The product is ideally suited for small to medium-sized charging stations with 4 to 32 charging slots in traction applications.