Powering an ALEXA cinema camera from front battery position on a sled by modifying jumper blocks and power cables

2013Batteries/Power forum

13 years old. Gear and prices may have changed since.

DisputedParticipants disagreed and reached no conclusion. Read the findings as positions, not as an answer.

A jumper block and Arri power cable can be rewired to supply 14V from a front-mounted battery to an ALEXA camera instead of the standard 24V from rear batteries.
When feeding 14V to an ALEXA, the low battery warning threshold in the camera menu should be adjusted from 22V to approximately 11V to prevent false low voltage alerts.
Using a single front Dionic HD battery (183 Wh) to power the camera in 14V mode can extend runtime to approximately 70 minutes.
The ALEXA uses 24V internally, making 24V power input more efficient than 14V.
Running an ALEXA at 12V requires higher amperage draw than 24V mode; a 12V power setup on Dionic 90 batteries exceeds their 6A maximum rating.
Dionic HC batteries (83 Wh, 10A max) and Dionic HCX batteries (118 Wh, 10A max) can safely run an ALEXA in 12V mode without exceeding current limits, unlike Dionic 90s.
Calculating battery runtime requires the formula: Watt Hours divided by (Voltage times Amperage) equals runtime hours.

The modification was made to one specific sled setup with particular accessories (Cooke lenses, Teradek, Preston motors, MDR2).
Battery runtime calculations are theoretical and do not account for real-world variations and actual usage patterns.
The claims about ALEXA internal voltage architecture are based on user reports rather than official specifications, except where Arri documentation is cited.
Multiple participants reported different battery life results with the same battery types, suggesting significant variability based on individual setup and usage.
The discussion includes unresolved disagreement about whether 12V parallel or 24V series configuration provides better battery life under real operating conditions.