2004Sled forum
Battery and charger configurations for Ultra sled film camera systems
22 years old. Gear and prices may have changed since.
What the thread found
- The standard Ultra sled package typically includes four batteries and a single-battery charger, which creates scheduling challenges on busy production days.
- A single charger is often adequate for moderate-pace feature shoots with planned workflow, where one battery charges while others power the camera.
- For faster-paced work or safety redundancy, owning two chargers and five to six batteries provides better operational flexibility and reduces risk if equipment fails.
- Quad chargers that sequence between batteries provide a practical middle ground, charging one battery at a time but immediately starting rapid charge on the next pack.
- Battery capacity can degrade over time, and older batteries in a package may only hold half the charge of new units.
- An Astroflight model 112 digital charger designed for radio-controlled aircraft can serve as an inexpensive alternative or backup charging option for 28.8V batteries.
- Stock Ultra batteries start around 30 volts when fully charged and drop to approximately 27 volts before declining faster toward 24 volts, the minimum safe voltage for nickel-cadmium chemistry.
- Dropping the Ultra battery voltage to 25.2V at 3Ah represents a modification that maintains functionality with 435 cameras, though standard voltage remains preferable for IMAX cameras that require 36-volt systems.
- For extended shooting with multiple cameras and recorders running simultaneously, six batteries with multiple chargers becomes necessary to maintain operations through a full production day.
Depends on
- Experience varies based on shooting pace and setup complexity; moderate-paced feature work differs significantly from high-speed, multiple-camera takes.
- Cold weather reduces battery efficiency and runtime substantially.
- Recommendations reflect nickel-cadmium battery chemistry; newer lithium-ion alternatives were emerging but at higher cost at the time of discussion.
- Astroflight charger accuracy may be limited by its low discharge rate during capacity testing compared to industry standard 1xC rating methods.
- Some observations are based on specific camera models like the 435 or IMAX, which have different power demands.