Knowledge Base

Why will the CoxBox not Take or hold a charge?

  • Is the CoxBox being charged correctly?
    • The battery should reach 100% FULL on the screen. Charging fully should not take longer than 10 hours.
  • Is the correct charger being used?
    • Our chargers are rated 12VDC and 300mA and are sent to the user with a special plug attached. We recommend that all chargers be purchased from NK, and that you do not modify a charger purchased elsewhere for use with a CoxBox.The old style and new style CoxBox chargers are interchangeable.
  • Is the charger working?
    • CoxBox charges without any errors displayed on the screen.
    • Does the unit charge with a different charger? If so, then the first charger is bad. If you suspect that your charger is not working correctly you can perform the following test:
      • Obtain a multimeter—almost any type will do. Turn the multimeter on and set it at 20 VDC. After plugging the charger in (be VERY careful, the charger is ON!), place the positive lead from the multimeter on the plus pin, and the negative lead from the multimeter onto the ground pin. The multimeter should read between 13.5V -15V. Any deviation from this range indicates that the charger is not working. If you do not get any voltage reading on the multi-meter, the internal transformer is damaged the charger must be replaced.
    • If the charger is not working correctly and you did get a voltage reading, it is probable that one of the pins has become disconnected or misaligned. Pins usually become misaligned due to debris in the plug—it is important to keep the plugs clean.
  • Why am I getting a charging error?
    • First you need to determine whether this is in an issue with the battery or with the CoxBox itself by swapping components.
      If the error follows the CoxBox first try cleaning all of the sockets using the CoxBox maintenance kit. Try charging again to see if this resolved the issue. If the error persists contact NK and we will work with you to get your unit repaired.
      If the error follows the battery, please try re-balancing your battery. If the error persists contact our technical support team at
    • Have the batteries exceeded their lifespan?
    • A CoxBox Battery is expected to provide 3 years of normal use (daily practices for approximately six to nine months of the year). If you know your unit’s batteries are older than three years, we recommend that the unit be returned to NK for new batteries and servicing. We can often check our records to determine the age of your unit’s batteries.