Yes—this is possible, and it’s a common approach in video rigs. A typical solution is a V-mount or Gold-mount battery system, which can power cameras and accessories like monitors through the appropriate taps, mounts, and rigging hardware.

For devices that don’t accept direct DC input, people often use dummy batteries and, when needed, DC-DC converters to match the required voltage for each device. A DIY version can also use a high-capacity 12V source with converters feeding the camera, monitor, and other accessories.

The main complication is flash power. Unlike cameras and monitors, many flashes use proprietary external power options or unusual input requirements, so they’re not always easy to integrate into a universal battery setup. Electrically it can be done, but it may require custom wiring/adapters and careful voltage matching.

So: one shared battery for camera + monitor is straightforward; adding flashes is possible but often the least standardized part of the system.