The amount of time it takes to charge a mower battery will depend on several factors, including the battery's size and type, as well as the charger you're using. Generally speaking, smaller batteries with lower charge capacities can take anywhere from two to four hours to fully recharge while larger batteries may require up to eight hours or more. Additionally, different types of chargers have different charging rates; some may be able to bring a dead battery back in just an hour while others could take much longer. It is important that you use the appropriate charger for your specific mower model so that you do not damage the battery or affect its performance.