Here’s a detailed summary of the Tether Tools Relay Camera Coupler CRND4 for Nikon EN‑EL18 batteries — what it is, how it works, compatibility, and things to watch out for.
Tether Tools Relay Camera Coupler — Nikon EN‑EL18 (CRND4)
What It Is
The CRND4 is a dummy battery insert designed to replace Nikon EN‑EL18 / EN‑EL18a batteries in compatible Nikon camera bodies. Tether Tools+2Polyline Corp+2
It does not contain a battery or store power. Instead, it serves as a power conduit, allowing an external 5 V source (via the Tether Tools Case Relay Camera Power System, CPS) to continuously power the camera. Polyline Corp+2Tether Tools+2
Key Features & Specifications
| Spec | Details |
|---|---|
| Model | CRND4 Polyline Corp+2Tether Tools+2 |
| Compatible Battery | Nikon EN‑EL18 / EN‑EL18a Tether Tools+2Polyline Corp+2 |
| Compatible Cameras | Cameras that use EN‑EL18 battery, including: Nikon D3, D2H, D2X, D2Xs, D3s, D3X, D4, D4S, D5, D200 Tether Tools+2acephoto.net+2. Note: For some bodies like D4/D4S and D5, a separate Nikon EP‑6 coupler might be required for compatibility. Tether Tools+1 |
| Cable Length | ~ 10″ (≈ 25.4 cm) from the coupler. Polyline Corp+1 |
| Total Cable Run with CPS | When connected with the Relay system cable, around 50″ (≈ 127 cm) total run. Tether Tools+1 |
Advantages / What It Enables
Continuous Power: Enables long shoots, time‑lapses, video, or live‑view sessions without needing to swap out batteries. Polyline Corp+1
Hot Swapping External Power Sources: Because the Case Relay system has an internal buffer (backup) battery, you can swap the external power supply (e.g. power bank) without losing power output to the camera. Tether Tools+1
Use of Non‑Proprietary Power Sources: You can use common 5V USB power banks, AC adapters etc., which are more universally available and often cost‑effective. Polyline Corp+1
Limitations & What to Check
The coupler does not have its own power storage; if both external power and buffer battery are unavailable or depleted, camera will lose power. Tether Tools+1
Battery door closure is essential; you must be able to fully close the door and route the coupler cable through the rubber trapdoor or cable port so the door can close properly. Failure to do so can cause poor fit, mechanical stress, or damage. Polyline Corp+1
For some models (notably D4, D4S, D5), additional “dummy battery adapters” (such as Nikon’s EP‑6 coupler) may be needed in conjunction for proper fit or safe use. Tether Tools+2Polyline Corp+2
Ensure your external power source provides stable current and voltage for camera usage, especially during high draw modes (video, bursts, extended live view). Cable quality and connectors matter, as voltage drop over distance or poor builds can cause issues.