Nikon EN-EL20a Rechargeable Lithium-Ion Battery Pack The Nikon EN-EL20a Rechargeable Lithium-Ion Battery Pack is a replacement or spare 7.2V battery with an 1110mAh capacity for the Nikon 1 V3 mirrorless digital camera. Lithium-ion batteries are long-lasting power sources that can be charged or discharged continuously without developing memory effect. It can be charged with the MH-29 battery charger.