Possible reasons for unexpected battery drain include:

  • Single cell battery failure
    • Normal alkaline batteries have a failure rate of close to 1%, which varies by brand
    • High temperatures or extreme vibration can greatly increase the failure rate
  • Activating Recovery Mode accidentally, and leaving it on
  • Inappropriate configuration, leading to excessive uploads
  • High levels of vibration, leading to excessive GPS checks
  • Cellular network connectivity problems, leading to excessive upload time
  • Rarely, a hardware fault, leading to sustained or sudden battery drainage

Diagnosing Battery Faults

If you have the unit in your hands, the best way to check for a battery fault is to measure the individual battery voltages with a multimeter. A normal alkaline battery has a voltage of 1.6 V when new, and less than 1.2 V when old. If one or two of the batteries has a low (or negative!) voltage, and the others are high, you can be sure you are looking at a battery failure. To determine if the failure was induced by temperature, you can check the maximum temperature reading on www.oemserver.com. First find your device, and click 'Details':

Then scroll down to find the Device Counters (available for firmware versions >= 1.29):

Normal alkaline batteries are rated for 55 °C. Higher temperatures will increase the chances of early battery failure. However, even in normal temperatures, commodity alkaline batteries are prone to occasional early failure. The brand we recommend for the best reliability is Panasonic Industrial. We do not recommend Duracell batteries, as despite their generally excellent battery life, they seem to have higher levels of early failure.

It may also be useful to graph the analog values of problem devices. On Telematics Guru, this can be done with the Asset Analogue Graph Report:

A battery failure typically shows up in the graphs as a precipitous drop-off:

In this example, excessive temperature in an engine bay cooks the batteries over several weeks:

Checking For Configuration Issues

In addition to checking the maximum battery temperature, the device details pane is the best place to check for Recovery Mode and excessive upload or GPS problems:

  • Check that Recovery Mode is not checked
    • For firmware versions >= 1.31, Recovery Mode will automatically disengage after the configured time, or 12 hour by default
    • For lower firmware versions, you must manually disengage Recovery Mode, or it will continue to increase battery usage
  • Check that the number of Accelerometer Wakeups is not too much larger than the number of Trips
    • It is normal for the Wakeup count to be 5-10 times larger than the Trip count
    • More than this indicates that the unit is often being woken up by vibrations / bumps in between trips, which wastes power on a GPS fix
    • If you are using the Upload On Jostle feature, the GPS Fixes Due to Jostle and Uploads Due to Jostle counts tell you how much extra energy the feature is using
    • If you are wasting too much power on unwanted wakeups, consider increasing the accelerometer wakeup thresholds, changing your install location to avoid the vibration, or disabling the accelerometer altogether
  • Check the ratio of GPS Fixes to Uploads
    • It is most battery efficient to have 10 or more fixes per upload, because uploads use so much more battery than fixes
    • The ratio is determined by the In Trip Logging Period and In Trip Upload Period, in the Basic Tracking section of the System Parameters
  • Check the ratio of Successful Uploads to Failed Uploads
    • A large number of failed uploads (>10%) could indicate a problem with the signal strength (bad install location), a problem with the antenna (cracked solder joint), or a roaming issue
    • See this article for details on checking the signal strength

Diagnosing Hardware Faults

While every Remora goes through a comprehensive QA check at the factory, hardware faults may occasionally develop in the field. Hardware faults that might manifest as a battery problem include:

  • A cracked Cellular antenna
  • A faulty tamper-detection cable causing a slow battery drain
  • A cracked capacitor causing a slow battery drain
  • Corrosion damage due to water ingress, causing a slow drain
  • A faulty modem or GPS, causing a fast drain on each upload or GPS fix attempt

To check for a cracked antenna, see this article. Checking for the other issues involves measuring the Remora's current draw with a mutimeter and benchtop power supply.

  1. Set your benchtop power supply for 6V
  2. Make extra certain that you connect the supply leads the right way round!
    1. Positive lead on the battery holder terminal with the red wire
    2. Negative on the terminal with the black wire and spring
    3. No seconds chances - if you get it wrong, the board will be destroyed
  3. If you want to accurately measure the sleep currents, set your multimeter to the milliamps range, and insert it between the supply and the Remora
  4. Now read the current levels off the benchtop supply or the multimeter
    1. Just after applying power, you should see 20-80 mA, while the cellular connection starts
    2. During the cellular connection, you should see around 100 mA on a 3G Remora
    3. After the cellular connection, the GPS fix starts, and you should see between 20 and 27 mA
    4. Eventually the Remora will go to sleep. It should then read 0 mA.
      • If you are using a multimeter, you can switch it to the uA range once sleep has started
      • You should see a base current of 3.3 uA
      • Plus 7 uA if the accelerometer is enabled
      • Plus 5 uA if the tamper detection board is present
      • Plus 16 uA if the GPS has seen satellites in the last 4 hours
      • Mind that you change the range back to mA before waking the Remora, as it won't work on the uA range
    5. Try wiggling the tamper detect connector, and check if this increases the current draw

If you observe excessive current, your board may have developed a hardware fault in the field. If it is still under warranty, and hasn't been subjected to water damage, your distributor will be able to help you with further debugging, repair, or replacement.