ONsite Relay A Coupler Bundle

ONsite Relay A Camera Power System (CPS) lets you power your camera continually with an external battery pack or wall power, providing peace of mind knowing you have an uninterrupted power source for your camera.


Select Your Camera

Relay Camera Coupler


Uninterruptible Power for Your Camera

With ONsite Relay A, you’ll never run out of power and never need to stress about forgetting your camera batteries. If you’re shooting and get low on battery power, simply swap out external batteries throughout your shoot. ONsite Relay A’s internal UPS battery will keep your camera powered while you exchange external batteries. Utilizing a wall outlet or external batteries, you could in theory shoot forever with consistent power flowing to your camera through ONsite Relay A.

How does it work?

A graphic depicting how the ONsite Relay A works

Simply insert the Relay Camera Coupler directly into the camera battery port, attach it to the ONsite Relay A Camera Power System and power your camera with any 5V 2.1A USB battery pack or an AC power source using a USB wall adapter. Because Relay also has its own secondary internal 1200 mAh battery, if your external battery runs low you can easily hot swap the external battery and not lose power to the camera.

ONsite Relay A is compatible currently with many Canon, Nikon, Sony, Panasonic, Fujifilm, Olympus, and Black Magic cameras and can be powered by any 5V USB power bank any 2.1+A USB Wall Adapter or any Dtap (VMount) battery system.  It can also power any monitors and accessories that use the Sony NPFL Series batteries.

Key Features:

  • The ONsite Relay A Camera Power System contains a 1,200 mAh battery, smaller than a traditional camera battery but enough power so you can swap out power sources mid-shoot and maintain 100% uptime.
  • The ONsite Relay A Coupler is designed to replace your camera battery and is not considered an after-market battery, just containing wiring. The Coupler cabling runs out the rubber trap door on your camera battery compartment or battery grip, and connects to the ONsite Relay A Camera Power System unit.

ONsite Relay A Camera Power System (CPS) lets you power your camera continually with an external battery pack or wall power (sold separately), providing peace of mind knowing you have an uninterrupted power source for your camera.

What’s included:

“We do Dog Show Event photography. The ONsite Relay A attached to the 10000mh battery powers the D750 that is tethered to our laptop. Before I got it we would go thru about 5 or 6 Nikon batteries in a day long assignment.
– B. Kurtis, Tether Tools Customer

Suggested Uses:

  • ONsite Relay A is ideal for time-lapse photography, astro-photography, or any photography that requires extended shooting time such as nature, fashion, landscape, architecture and more.
  • ONsite Relay A is ideal for video production as you can swap the External Battery Bank, without having to stop shooting to change camera batteries.
  • Use it to power Photobooths to ensure consistent uptime throughout an event.

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“It’s perfect to power my second Sony A7S II camera during weddings. Because I’m not with eyes on the camera most of the time, it allows me to connect any power pack. The most important thing is to allow swapping power banks without loss of power and corrupted files.”
– P. Portela, Tether Tools Customer

ONsite Relay A attached to a tripod in the foreground and a majestic waterfall in the background

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“I’ve used it to shoot a three months time lapse!!!!!!! It was a place without electric power so it has been super useful!!!!!!!”
– D. Pepe, Tether Tools Customer

Product Specifications:

ONsite Relay A Camera Power System

Relay Coupler

  • Relay Coupler is simply an insert for your camera battery cavity that enables powering the camera via ONsite Relay A Camera Power System. The coupler does not contain a battery or hold a charge.

What is the Proper Way to Connect the ONsite Relay A? Here’s the Recommended Connection Sequence:

  1. Keeping the cables unconnected, insert Relay Camera Coupler into camera, completely close door.
  2. Connect the ONsite Relay A to the power source.
  3. Connect the Relay Camera Coupler to the ONsite Relay A

More questions about the ONsite Relay A? Check out our FAQ and instructions page.

Find Your Relay Camera Coupler

Relay Camera Couplers from Tether Tools work in tandem with the ONsite Relay C and ONsite Relay A to keep your camera powered continually with an external USB battery pack, D-Tap battery, or wall power.

Chart of compatible cameras and couplers

What’s Included: