Here’s a detailed product breakdown for the Tether Tools Relay Camera Coupler for Canon Cameras with BP‑511 Battery (model CRC400):
What It Is
The CRC400 Relay Camera Coupler is a dummy battery insert designed specifically for Canon cameras that use the BP‑511 / BP‑511A battery. It is part of the Tether Tools Case Relay Camera Power System (CPS). When installed in the camera’s battery compartment, it allows the camera to be powered continuously by external 5 V sources (USB battery pack, wall adapter, etc.) instead of relying on the internal battery. The coupler itself does not store power — it merely passes power from the external source into the camera.
Key Features
Replaces the BP‑511 / BP‑511A battery in Canon cameras. Tether Tools+2B&H Photo Video+2
Works only with the Case Relay Camera Power System (CPS) — you need the Relay power unit or compatible external power source to use this coupler. Tether Tools+1
Includes a built‑in cable (≈ 10″ / 25.4 cm) from the coupler to the Relay power cable. Studio Depot+1
Allows the camera’s battery door to completely close; the outgoing cable runs through a rubber “trap door” or grommet. This helps keep the connection safe and avoids strain on connection points. Tether Tools+1
Compatible Cameras
Cameras that accept the BP‑511 / BP‑511A battery can use this coupler. Some of these include:
Canon EOS 5D B&H Photo Video+1
Canon EOS 50D B&H Photo Video+1
Canon EOS 40D B&H Photo Video+1
Canon EOS 30D B&H Photo Video+1
Canon EOS 20D, 10D, and earlier models like D30, D60 Tether Tools+1
(Always check for your exact model’s battery compatibility before purchase.)
Technical Details & Limitations
| Spec | Details / Notes |
|---|---|
| Coupler cable length | Approx. 10″ (25.4 cm) from camera‑battery slot to the Relay cable. Studio Depot+1 |
| No battery in coupler | The coupler draws all its power from the external Case Relay system; it does not provide backup battery power on its own. Tether Tools+1 |
| Battery door must close fully | For proper operation and safety, the camera’s battery door should completely close, and the cable exit should be routed via the designated cord trap/door if available. Tether Tools |
Benefits
Allows long continuous use (video, time‑lapse, studio shoots) without constantly swapping out Canon BP‑511 batteries.
Uses non‑proprietary external power supplies (USB power banks, AC adapters) which are often more convenient & portable.
Cost‑effective over time if you shoot long sessions, since you don’t need a stock of BP‑511 batteries.
The Relay system supports “hot‑swap” of external power bank sources without losing power to the camera (thanks to the Relay system’s internal buffer). Tether Tools
Things to Keep in Mind / Limitations
Since the coupler doesn’t hold charge, if the external power source dies or gets disconnected, the camera will lose power unless the Relay system’s internal buffer (UPS) is in use.
Cable routing is important: avoid sharp bends, tension, or tension at the battery compartment door, which could damage the cable or compromise the door’s closure.
Heat or load: powering camera in Live View or video mode adds power consumption; external supply/wiring must be adequate.
Compatibility: BP‑511 battery dummy doesn’t fit all Canon models — check compatibility; older or newer models may use different battery types.
If you like, I can prepare a clean, ready‑to‑use web/catalog product description for CRC400, or compare it side‑by‑side with some competing solutions to see how it stacks up.