The PowerBase 70 Battery Pack from Switronix contains a 70 Wh, 14.8V Lithium-ion battery designed to extend HD movie recording time for the Canon EOS 5D Mark II and 7D digital cameras. The PowerBase 70 delivers six times more power than the original battery supplied with the camera. It is also intended to streamline your High Definition (HD) movie recording: the PowerBase 70 mounts under the camera and doubles as a grip or can be attached to an HDSLR support via its 1/4"-20 release plate or V-Mt mount.
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). The pack is also furnished with 1/4"-20 threads on either side to mount accessories.
This is a live saver for powering the blackmagic cinema camera
Just got this in for use with my Blackmagic Production Camera 4k today. I haven't used it with the camera yet, so I can't say anything about it's battery life, but when comparing power solutions for my Blackmagic I had some difficulty finding all the information I wanted, so I felt compelled to share with you what I know here now that I have the battery in hand. The battery itself is a V-mount brick. The opposite face of the V-mount has a small quick-release plate with a 1/4" screw, so that you can mount the plate to your Blackmagic and easily remove and attach the battery as needed. You can also use this plate to attach any number of accessories, including another battery if desired. In addition to the face with the 1/4" screw, both sides and the V-mount back also contain 1/4" threads, so you've got a lot of options on how to attach this to your rig. The contact block connects to the bottom of the battery and should never have to be detached so long as you're using the same camera. The contact block has the cable that connects to your Blackmagic, and it is, as other have remarked, pretty darn short. I can't say much since I haven't connected it yet, but it's definitely shorter than a foot and I expect to have my rigging abilities limited by this. Fortunately, you can buy extension cables if it's THAT big of a problem. And of course, there's a power indicator on the side. Push a button and you've got 4 LED indicators to tell you how much charge you have. The only problem I've encountered thus far is with the plastic molding of the battery. It took a lot of force to get the charger cable plugged into the battery, and I definitely chipped parts of the plastic off doing so. It simply did not fit without using a frightening amount of strength and hearing a frightening amount of snapping, and it doesn't get any easier when pulling it out or putting it back in. Weird and annoying, sure, but a small complaint in light of all the other pros of this battery.
The Switronix is a pretty reasonably priced battery solution for the Blackmagic Cinema Camera. You essentially get a V-Mount, but with bonus option of being able to mount directly under your camera for flying with a smaller rig, handheld, or on a jib. I tend to mostly use this with a v-mount plate and run out to the camera, and I discovered another bonus of the quick release plate is that I could mount my H4N recorder directly to it for good run and gun audio on the fly, as well as additional counterweight when handheld. Really the only downside to this battery is capacity, doesn't last quite as long as standard v-mounts. But its slightly smaller and more lightweight, and offers more versatility so it seems to even out to me.
I have only used the battery pack a couple of times and it's great so far. I recorded a 2.5hr interview and by the end of it I still had over half the battery capacity left. Just awesome. The only issue I have is the mount which is plastic and has a little play in it. Unfortunately, if you use the battery pack as a handle, the camera wobbles slightly on it. I figure I can customize with a little piece of electrical tape to stop the wobble.
This is a must have for the BMCC user. The extra shooting time allows ytou to capture those magic moments with the worry of running ou t of battery power. It also allows for intergration of many support devices...i.e.; monitor, audio, etc. The second most important piece of equipment a must for all levels of pruduction.
I wish it charged faster, but I am using the little P-tap charger.
It works great, but is as big as a barge. There are no directions or manual and beware, the wall recharger is sold seporately!