Batteries and Power
I'll get right to the point on batteries: You can never have too many. On a typical shoot day, I turn on the RED at 7 in the morning and turn it off when the sun goes down. That can mean anywhere from three to five battery changes per day. When a battery comes off the camera, it immediately joins its brothers on a plugged-in charger when we're in the studio or a location that offers AC power, which isn't always the case. Don't wind up having your shoot day curtailed by the last battery going out.
I suggest getting at least two, if not four, RED Brick batteries ($450) per camera body. Or grab a RED Power Pack ($1,450), which is great because it includes two batteries and simultaneous charging capability for both. With two RED Power Packs and a RED cradle ($750) to mount onto the camera, you'll be all set.
If you happen to have a stock of Anton Bauer camcorder Hytron 140 batteries (www.antonbauer.com), you'll want to get its special adapter that fits onto the RED. RED also offers a 12V DC charger ($85) to connect to a car or boat DC power outlet. It can come in handy if you expect to be away from available AC power for most of the shoot.