Posted 08 November 2017 - 03:23 AM
I don't remember exactly but the current draw is probably around 2 - 3 amps with a load and basic accessories, so you should get a good couple of hours at least with 7Ah cells.
The voltage upper limit will be above what your 24V battery will supply fully charged, and once it drops below about 21 or 22V you'll want to swap out the battery to preserve the cells, rather than the camera. The camera might keep running with far less voltage (although not necessarily at speed), but the cells can become imbalanced and potentially damaged if you drain them down too low.
The rental house I used to work at supplied 26.4V block batteries, which can reach well over 28V when fully charged, but they never damaged the cameras, which included Moviecams. So you have some room over 24V before the camera circuits will fry.