Stihl AP 20 BatteryAP 20 Battery: Lithium Ion 144 Wh battery 36 V, 4. 0 Ah Lithium Ion battery. The AP 20 is an entry level battery that powers some tools within the STIHL AP System. With an energy capacity of 144 Wh, the battery has an integrated LED charge indicator, clearly displaying as and when the battery needs charging. Ideal for lighter gardening and landscaping tasks, the AP 20 is suitable for domestic, semi professional and professional users. Durable and IPX4