Some might see this as overkill, others may see it as an incredibly versatile solution. Especially for those opting to move into the new Sony Camera systems (A7sII / A7RII) that have poor battery life, you'll definitely be looking into some type of external power solution.
The Switronix PB-70 is a unique battery system as it can work as a normal V-Mount battery to power up your LED Lights, but can also double as an external battery solution for many camera systems (including BlackMagic, Canon, etc). Sure you can use other V-Mount batteries to power your camera, but the mounting solution incorporated into this particular V-Mount from Switronix is what makes it clean, simple, and minimal.
Switronix PB-70 Review Video by SatoStudioGear.com
A small quick release adapter first mounts under your camera (or cage) similar to a battery grip. This allows the Switronix PB-70 battery to attach under the camera. And under the PB-70 battery itself is another tripod mount, so you can attach another Tripod QR plate directly to the PB-70 battery. It works very similar to standard camera body battery grip.
Of course the Switronix Powerbase does not really have to mount under a camera body, as it only needs a 1/4-20 threaded mount. This can be mounted to the top of a Blackmagic 4K camera, or on a cheese plate off a shoulder rig. By incorporating these creative mounting options into a V-Mount battery is what makes the PB-70 a versatile battery system.
There are smaller, lighter, and cheaper power solutions for the Sony A7 cameras, but the capacity of the Switronix PB-70 means you can run all day (if not several days). And when mounted to your camera, it still has Two P-Tap out for you to power two other accessories at the same time (on camera LED light, external monitor, etc). And when not used with your camera, your investment means you can still use the PB-70 to power your Large 1x1 Studio LED Light Panels - incredibly versatile.