The iKan Blackmagic Single Rod Mount for Canon LP-E6 Battery will give you the freedom of extra battery life for those longer shoot days. This inexpensive element piece mounts to any standard 15mm rail and works with multiple DV batteries.
iKan BMC-PWR-1RD-E6 Features
Mounts securely to your rails
Can be added to your rig without adding weight
It will give the user added battery life for the camera