Switronix has a portable battery PowerBase- the PB70, available for the Blackmagic Cinema Camera. The BMCC is not made to shoot solely using the internal battery. In fact, the battery cannot be removed at all. This cinema camera is intended to run on an external power source via the Power 12V-30V input while the internal battery acts more so as a safety backup.
Switronix has come up with an external battery solution that pretty much acts like a battery grip. The Switronix PB70-BMCC PowerBase-70 Battery Pack for Blackmagic Cinema Cameras connects to your BMCC’s underbelly with a provided quick release plate. The battery pack itself also has a 1/4-20″ female thread at its base for mounting onto rigs or tripods. Wired as a 14.8V battery pack, it can provide extended power for up to two additional 12VDC devices such as lights, monitors or HD converters as well as other devices requiring lower voltage (an optional XP power regulation cable is needed). Switronix can make a 24″ cable for $17 ($10 for cable extension, $7 shipping). They don’t offer these in production, but they will custom make them for customers.
14.8V, 70Wh, 4.8Ah
6x More Power than Internal Battery
Auxiliary Power Output (12VDC)
V-Mount with Quick Release System