Portkeys BD4 Dummy Battery Power Adapter Dual Output - Flexible Rig

Our review of the Portkeys BD4 Dummy Battery Power Adapter finds it aimed squarely at camera operators who need a compact, rig-friendly way to power both an NP-F monitor and a V-Mount wireless video transmitter from a single source. The biggest reason to consider the BD4 is its pass-through power design that accepts either 15V USB-C PD or a 7~16.8V DC input and delivers separate outputs to a monitor and transmitter, reducing battery swaps and clutter on run-and-gun shoots.

Key Features

• Dual power outputs: Simultaneously powers an NP-F monitor and a V-Mount wireless transmitter so you can run both devices from one input source without extra batteries.
• 7~16.8V pass-through: Accepts a wide voltage range via USB-C or barrel DC input to keep varied equipment running under different power conditions.
• USB-C and DC compatibility: Supports 15V USB-C Power Delivery (PD 3.1) and 7~16.8V DC barrel input so PD power banks or D-Tap supplies can be used on location.
• Switchable mounting: Repositionable design with a tool-free 1/4' thumb screw allows quick conversion between vertical and horizontal mounting for cages and gimbals.
• Rugged compact build: CNC-machined aluminum alloy with ABS inserts provides a lightweight yet durable housing that stands up to mobile use.
• Integrated protection: Built-in safety circuitry guards against over-current, reverse polarity, and short circuits for safer hot-swapping on set.

Who It's For

The BD4 is best suited to indie filmmakers, run-and-gun shooters, and camera operators who need a tidy way to feed both a monitor and a wireless video transmitter from a single battery or USB-C PD bank. Its small weight and repositionable mount make it a good fit for cage-mounted setups and gimbals where space and balance matter.

Those who should look elsewhere include users who require integrated charging of internal batteries or models that rely exclusively on a single proprietary mount standard; the BD4 is a pass-through adapter designed to bridge power between external supplies and accessories, not a full replacement for high-capacity V-Mount battery solutions.

Pros & Cons

Pros

• Compact, durable CNC-machined housing that keeps rig weight low while resisting wear.
• Flexible input options with USB-C PD 3.1 and DC barrel input, plus included D-Tap to DC cable for location batteries.
• Tool-free vertical or horizontal mounting adapts quickly to cages and gimbals.
• Safety circuitry for over-current, reverse polarity, and short-circuit protection supports hot-swapping.

Cons

• Some customers report mixed experience with the USB-C port functioning reliably, so verify compatibility with your PD source before critical shoots.
• As a pass-through adapter it does not replace a dedicated high-capacity V-Mount battery for extended runtimes.

Specifications

Product type	Dummy battery power adapter
Outputs	NP-F monitor and V-Mount wireless transmitter
Input	15V USB-C PD 3.1 or 7~16.8V DC barrel
Mounting	Switchable vertical or horizontal with 1/4' thumb screw
Construction	CNC-machined aluminum alloy with ABS inserts
Protection	Over-current, reverse polarity, short-circuit
Weight	204 g

Our Verdict

The Portkeys BD4 is a practical adapter for operators who want to power a monitor and wireless transmitter from a single USB-C or DC source without adding bulk. It offers useful mounting flexibility and solid protection circuits, making it good value for filmmakers who prioritize a compact, rig-friendly power solution, though users needing long V-Mount runtimes should still pair it with a dedicated battery system.

Frequently Asked Questions

Can the BD4 be powered by a USB-C power bank?
Yes, it supports 15V USB-C Power Delivery (PD 3.1), so compatible PD banks can be used as the input.

Is a D-Tap cable included for rig batteries?
Yes, a D-Tap to DC input cable is included to connect D-Tap-equipped batteries.

Will it charge NP-F batteries?
No, the BD4 provides pass-through power to accessories; it is not designed to charge internal NP-F battery cells.