RAK811 Tracker Power Use..



  • Hi,
    Same problems here with similar power consumption.. Replacing UBS_POWER to BATTERY_POWER in GetBoardPowerSource() to enter low power mode seems to prevent board from transmitting LoRa packets (is that interrupt does not work and never switch to normal mode?), I could not test power consumption yet in this mode . @stuartw does your node still emitting when you enable low power mode?



  • @rakadmin I have the same issue, any news?



  • Still nothing back on this?
    This is quite a major issue, and would force me to look at another platform if we cannot resolve it.
    @rchaudet, I take the approach of transmitting in normal mode, then sleeping for a long period, however that seems to be pointless as it uses the same power when sleeping - therefore there is no point in sleeping.

    There seems to be no updates from RAK on this - I am starting to think this may be a quickly abandoned product?

    a Sleep mode that doesnt sleep, based on IoT/Low Power components seems... broken to say the least.
    I really hope we can get an update on this.



  • @stuartw They made the board user-friendly to test basic features but definitely not for low power (in hardware design):

    • the power led is hard wired to battery, wherever you plug the battery, wich will already prevent the board from consumming less than 2-3 mA.
    • voltage regulators (MIC5219 & built-in USB/UART regulator) allow user to supply the board with a wider range of supply voltage but consumes a lot.. MIC5219 is always on since EN pin is connected to VBat, same for USB/UART regulator even if it consumes less in SUSPEND mode (I does hope it actually reaches this mode when usb is not plugged, i couldnt test it yet). It is way more suitable to use primary cells without regulators to achieve low power consumption.
    • Rak811 module itself is actually not bad for low power, (some people managed to get consumption in µA in sleep mode) and in my case the low power mode does work in the tracker board: consumption drops from 30mA to 26mA, which is still quite big but related to other components consumption.

    @rakadmin Would the Rak811 tracker board Gerber files be available? in order to propose some modified design adapted to very low Power. By the way, what is the purpose of TPS27082LDDC module since it seems that Ublox Max7Q already handles ON/OFF mode via EXTINT pin? (according to Ublox doc)
    Thanks



  • Seems like a pull-up resistor is missing at R1/C1 pin of TPS27082LDDC, preventing the GPS from being shut down whatever the ON/OFF level is (pin PA15).



  • @rchaudet You can give us your hardware design suggestions for low power consumption. We will update the hardware design in the next version.



  • @rchaudet said in RAK811 Tracker Power Use..:

    Seems like a pull-up resistor is missing at R1/C1 pin of TPS27082LDDC, preventing the GPS from being shut down whatever the ON/OFF level is (pin PA15).

    Thanks for your suggestion, we have revised this issue and the new version has been updated.



  • @rchaudet, Yes, I well know there are physical limitations on this board, however it still appears to me that the software as delivered is not sleeping the primary CPU.
    30mA to 26mA does not represent enough of a change for the CPU itself to be going correctly in to sleep, dont you agree?

    If fact of that matter is that if the board cannot be slept, then it is of no use. It is quite a trivial matter for development to self-integrate GPS, INS, etc on the a simple module, and a lot more flexible that the dense board as supplied - the only reason for it to be a useful product is if it actually works.

    And for it to work, it must be able to sleep at less mA, it is after all conceptually designed as a low power tracker, otherwise what is the point of the onboard LoRa?

    I agree that gerber files would be very helpful in working out what is wrong, but again, why use the board if it cannot function as intended. Why have a 'sleep' mode that cannot sleep the board enough to be worthwhile.



  • Also battery monitoring should have a zero drain current with something like that

    Zero Drain current

    Check this repo



  • Also MAX-7 support low power modes, and should be possible to adjust it over serial. For now I just have GPS <-> USB bridge.
    https://github.com/goran-mahovlic/RAK831-GPS-FORWARDER
    But still was not able to set it up in Low power.
    But from windows I can see what module is sending ...
    0_1525635335881_GPS-RAK-wireless3.png


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