We rent the EBL 18650 3.7v 3000mAh Li-ion Rechargeable Battery 2-pack as spare batteries for the Tilta Nucleus-M Wireless Lens Control System. A fully-charged pair of batteries will power the FIZ hand controller for up to 10 hours and each handgrip for up to 48 hours. If you need extra chargers, we rent the Tilta Nucleus-M Battery Charger separately.