STIHL batteries can be charged with either the AL 100 standard charger or the AL 300 quick charger. Each charger features a different charging capacity (Watt). The AL 300 has active cooling for even faster charging. When used for prolonged periods - by professional gardeners, for example - you are advised to use two batteries to save time.
A comparison of battery charging times
The batteries can be charged several hundred times without any appreciable loss of energy. Here you can see an overview of the required charging times of the various batteries.