STIHL AL 501 HIGH-SPEED CHARGERSTIHL AL 501 HIGH SPEED CHARGER Ap Battery System You can use the STIHL AL 501 quick battery charger to ensure you lose as little time as possible when charging batteries. All STIHL AK batteries, STIHL AP batteries and STIHL AR batteries can be quickly recharged with the STIHL AL 501 quick battery charger. Active battery cooling protects the batteries during charging. The operating status display uses an LED to indicate how far the charging process