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ago in Vehicle tracking by


Our FMB920's are shutting down after about 30-60 min, they are connected to a external 9V battery with 800mAh. Ignition and movement source are configured on Accelerometer. When I disconnect and reconnect them, they become online again and I can see that the internal tracker battery has enough power (60%). These trackers are working 3hours a day only and configured on Deep Sleep after a timeout of 15min.

Do they need a minimal 12V power supply to operate stably?

ago by
I believe fmb920 works down to 6v,  I'm not sure if it will charge the internal battery at such low voltages though. From my testing it starts charging at about 10V on the external.
ago by
Ok, the external battery has a capacity of 150mAh instead 800mAh. I have connected the trackers now to the right high capacity batteries. This is a temporary solution for us. Later they will be connected to a 12V power supply.

I have noticed that when the FMB920 has no efficient power supply connected, it is shutting down, also when there is sufficient internal battery capacity. that is weird. For example it is shutting down while current internal battery is 60%.

Btw, the internal battery is charging till 80% when connected to a 9V 800mAh li-on battery.

The devices are active for about 3 hours a day. For the rest of the day they are in Deep Sleep mode.

1 Answer

–1 vote
ago by
Hello ecmir,

Good day. Thank you for your question.

The advised external voltage is at 12V and the device will charge normally up to 10V. However, when the voltage drops below 10V, it depends on the current usage of the battery that determines that charge where if the incoming power is less than consumption then the internal battery will take over the power supplication. This is why you will experience the device only lasting up to 30-60 minutes of device up time. However, if the device is under sleep mode then there will be a very low consumption which is why your device is able to last up to 3 days or more.

Hope this clears your doubts.

Kind regards.