Case Relay Instructions and FAQ

case relay


Q: Which Relay Camera Coupler do I need for my camera?

A: The Case Relay Camera Power System is compatible with many Canon, Nikon, Sony, Panasonic, Fuji, and Olympus cameras. To use the Case Relay, you’ll need a Relay Camera Coupler for your specific camera. To find the correct Relay Camera Coupler, check the compatibility chart at

Q: How do I know when to swap out my external battery pack?

A: Case Relay’s indicator light will show one of three colors – green, yellow or red. This is an indication of the charge in the Case Relay. Green means it’s fully charged. Yellow means it’s 70-30% charged and red means it’s less than 30%. If Case Relay is flashing, that means it’s not connected to a power source.

Q: What can I plug the Case Relay into for power?

A: Case Relay can either be plugged into a 5V USB external battery pack or as an alternative into a wall outlet using a USB wall adapter. The wall adapter should provide at least 2.1 amps of power. The Tether Tools Dual USB AC wall adapter offers 2.4 amps and two USB ports to power multiple devices at once. In this setup, you may want to use a USB extension cable between the case relay and the wall outlet for added length.

Q: Can I plug my Case Relay into any external battery pack?

A: Case Relay will work with any 5V USB external battery pack. Tether Tools offers the Rock Solid External Battery Pack which is a 10,000 mAh rechargeable power source.

Q: I already have a camera battery; why would I want to use the Case Relay CPS?

A: Traditionally, when your camera battery dies, you have to stop your time-lapse, video or studio session, pull out your battery and put a new one in. With the Case Relay that’s a problem of the past. Simply disconnect the battery pack from Case Relay and power your camera with a 5V USB external battery pack or USB wall adapter. Your camera never loses power and you never stop shooting.

Q: Why isn’t my 11V input camera, such as the Canon 1Dx series, supported?

A: If your camera can be charged with 7-9V voltage, the Relay will can support them. Approximately 95% of cameras use 7-9 V power supply systems, so Relay can support most cameras if they have a coupler. Certain cameras such as the Canon 1D series use 11V input, which Relay can’t support.

Q: Is the Nikon D500 or Nikon D850 compatible?

A: The Nikon D500 and Nikon D850 will work with the Case Relay, however, because of a proprietary battery chip, Tether Tools does not have a camera coupler that is compatible. You will need to purchase the coupler direct from Nikon in order to use the Case Relay. The official Nikon Power Supply EP-5B is found here.

Q: >What is the best USB wall adapter amp to use?

A: We recommend using a USB to AC wall adapter that has a 2.4A/5V output such as the Tether Tools Rock Solid Dual USB to AC Wall Adapter.

Q: Does Case Relay work well in cold weather/hot weather?

A: The Case Relay’s internal lithium battery is best charged at temperatures between 0°C to 45°C (32°F to 113°F) and discharged in temperatures between –20°C to 60°C (–4°F to 140°F). Do not charge when weather is below freezing. The Case Relay’s internal lithium battery will charge and perform well at higher temperatures but may experience shorter life.

Q: Can Case Relay damage my camera?

A: No, the Case Relay is safe to use for your camera. It’s important to note that the Relay Camera Coupler (the piece that is inserted into your camera battery port) does not contain a battery.

Q: I have a battery with less than 2.1A can I use that?

A: Yes, you can but the lower power input, the shorter the continuous power supply such as video recording time. For 5V 2A, we are confident that it is enough to power to continuously video recording with no stops. If you’re using a 5V 1A or 5V 500mA external battery you may have to break a moment if the Case Relay battery is empty.

Q: I have a battery that provide more than 2.1A, can I use that? Will it harm my camera?

A: As long as the voltage is 5V the external battery pack is safe to use with the Case Relay. The printed voltage on your power bank is the max capacity the port can output. The final output of the Case Relay is fix to 8V, so it will not hurt your camera.

Q: My battery has an automatic shutoff feature. Will this work with Case Relay?

A: No. Since the Case Relay trickle charges the internal battery, there may be times where the Case Relay’s internal battery is completely charged and not pulling power from the external battery. If the external battery turns off, when the Case Relay goes to grab more power from it, it may not be able to get any. Most external batteries will turn back on when detecting a need to supply power, so this is a case by case situation.

Q: When I use Case Relay the camera battery indicator does need seem to be accurate. Is there a way to identify battery level through the camera?

A: You can check the battery level through the camera if you use a Relay Camera Coupler purchased from Tether Tools.

Q: Can I use the USB port from my computers?

A: We don’t suggest that as it may damage your computer’s USB port.

Q: Can I change power bank when the camera is on?

A: Yes, you can and it’ll continue to power the Case Relay and your camera.

Q: Can I use Relay to power other cameras not on your supporting list?

A: Since most cameras use 8V power system, Case Relay can support your camera if you have access to a suitable camera coupler. If there’s a coupler not on our supporting list that you’d like Tether Tools to sell please email us at

Q: Why does the Relay fail to fire on my Canon 5D Mark II?

A: On certain cameras it’s imperative to first connect the Relay Camera Coupler and Case Relay first before inserting the Relay Camera Coupler into your camera.

Q: Why does my Sony A7II show the incorrect power level?

A: The issue is with the power level display only. The camera will continue to get power from the Relay as long as the Relay is charged and connected to an external power supply. The Relay Coupler is not relaying the correct power levels to the Sony A7II family of cameras as the power decreases. Initially, it reads properly, but the power meter will keep decreasing no matter if the Relay is charging. If the power meter on the camera decreases to 0%, the Relay will still power the camera. You will need to monitor power levels using the Case Relay LED and external battery.

If you turn the camera off and reconnect the Relay, the power percentage indicator will go back to the true level then decrease again. This does not affect the first generation of A7.

Q: What are the connection specifications for the barrel jack between the Case Relay and the Relay Camera Coupler?

A: The connection is 5521, which means 5.5mm outside diameter and 2.1mm inside diameter.

Q: How do I close the camera battery door?

A: The camera should have a rubber trapdoor. Feed the coupler cable through this rubber slot and then close the door completely. Battery door must close all the way for coupler to work

Q: What is the proper way to connect the Case Relay?

A: Connection sequence- Keeping the cables unconnected, insert coupler into camera, completely close door. Connect the Case relay to the power source. Connect the coupler to Case Relay.