Cornick Help Center

    Resolve HDCVI / Analogue Camera's Dropping out at Night

    August 10th, 2020

    If you experience the issue of HDCVI or analogue cameras dropping out and not recording at night, this is often due to voltage drop across the cable.

    The reason this usually occurs at night, is because the camera draws the most power as the Infra Red LED's have turned on. The camera will usually restart and show colour bars, then go black and repeat the cycle.

    Power Supply Requirements

    Before checking for voltage drop, check the camera specifications for voltage and current draw. These specifications can be found on the product brochure, or on the camera itself.

    If you camera requires 12V DC and 1 Amp, ensure the power supply meets the requirements. If you have 4 cameras drawing this amount connected to a single power supply, your power supply must be 12V DC 4 Amps. If you power supply is not meeting the cameras needs, you will experience the same symptoms as voltage drop across the cable.


    How to Check for Voltage Drop

    Before beginning, a multimeter, 1x Male DC Jack, 1x Female DC Jack, and a piece of figure 8 wire is required.

    1. Locate the camera's power supply and disconnect the cable running to the camera.

    2. Using a multimeter, measure the output of the power supply. Record your findings.

    3. Reconnect the power supply to the camera.

    4. Locate the camera that is experiencing issues, and get access to the power connector at the back at the camera.

    5. Using a multimeter, measure the voltage at the camera while the camera is connected. Record your findings. The easiest way to make measure voltage if the camera has no points to check with a multimeter, is by using 1x Male DC Jack, 1x Female DC Jack, and a piece of figure 8 wire connected as below.

    6. Repeat step 5, this time covering the front of the camera forcing it into IR mode. Record your findings.

    Below are our findings, your findings will vary depending on cable type, and distance.

    Note that the Voltage at the camera is 10.7V which is far from what it should be, at 12V.

    Voltage at Power Supply Voltage at Camera
    - Day Mode
    Voltage at Camera
    - Night Mode
    12V 11.6V 10.7V

    Rectifying Voltage Drop

    Once you have identified the camera is experiencing voltage drop, there are multiple methods to resolve it.

    Method 1: Replace Camera Power Supply

    In some cases it is possible to use an adjustable power supply to account for voltage drop. Check the specification of the camera your are working with to see what the input tolerance is, most cameras are usually 10%, meaning a some 12V cameras can safely run at 13.2V.

    When installing the power supply, disconnect the camera first, and adjust the power supply to 12V. Connect the camera, and slowly adjust the power supply until the camera reaches the desired voltage when in day mode. Use a multimeter while adjusting the voltage to ensure the correct voltage is reached.

    When installing a adjustable power supply, ensure that it does not exceed the cameras maximum voltage rating, as the camera will no longer work.

    Cover the front of the camera forcing it into IR mode, and ensure the camera does not drop out.

    Method 2: Replace Camera Cable

    Depending on the difficulty of the cable run, replacing the cable may be an option.
    The existing cable that is installed may be too thin for the distance of the cable run. This can also happen if multiple pre-terminated cables that are joined together.
    Before replacing the cable, it is recommend to use a voltage drop calculator to ensure this procedure will rectify the issue. The cable must be replaced with a thicker cable, how thick will depend on the length of the cable run.

    Method 3: Double up pairs (When using CAT5 Cable with Baluns)

    If the camera is running over a CAT5 cable using baluns, one pair (2 wires) of the cable should be used for video. The other pairs of the cable should be used p to send voltage to the camera. There will be one pair for video, one pair for Voltage +, and one pair for Voltage -. There will be a remaining pair which can be split, and one wire used for Voltage +, and the other for Voltage -.

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