@tomasmcguinness

Low power consumption on HolyIoT nRF54L15 dev kit

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A week or two ago, I received a HolyIoT nRF54L15 DevKit and two modules that I ordered from AliExpress.

I’m trying to choose a module to use for my Matter Dual Temperature Sensor project. These modules seemed pretty good. They had castellated pins, meaning I could solder them and they didn’t cost the earth. The company also offered a DevKit, so this seemed like a good addition.

When I received them, I hooked them up and flashed them using my JLink device. You can read about that here

Testing my HolyIoT nRF54L15DK

With the board working, I turned my attention to power consumption!

Being Naive!

I just assumed that I’d have a great out of the box power experience like I did with the nRF52840DK. Sadly, I was wrong!

I started with the system_off sample, which can be found here

~/ncs/v3.1.0/zephyr/samples/boards/nordic/system_off

The power consumption was ridiculous!! As you can see in the diagram below, it sat at 2mA, expect for the 4mA peaks. These were the button presses to wake it up (describe in the sample)

The 4mA peaks were times I held down the button as described in the README.

I loaded the same code into the official nRF54L15 development kit and the results were a galaxy apart. The official board drew 1µA. As the specification said it should.

Pushing the button caused consumption to jump to around 3mA, which is accounted for by the LED.

2mA is what, 2 million times more than 1µA.

No help was forthcoming

In the system_off sample, I commented *everything out*, all but the call to sys_poweroff().

Consumption remained at 2mA. WTF? I was sure that would have made some difference!

Experience had taught me that I needed help at this point! I contacted HolyIoT and asked for help – a sample, anything at all!

Unfortunately, all I got back was a pointer to the system_off sample 😦

Giving Up

There was clearly some component on the dev kit or in their module that was drawing massive amounts of power.

I don’t have the expertise, or time for that matter, to try and delve in any further. I will keep trying to get some answers from them. Until then, I’m going to see if I have more success with the Minewsemi module and DevKit

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8 responses

  1. DARKMAN Avatar
    DARKMAN

    Tried deepsleep between tasks?I’m also searching for nRF that is ultra low power.

    Reply
    1. Tomas McGuinness Avatar
      Tomas McGuinness

      With that particular board, going to power off didn’t help 😂

      When using Matter’s ICD, deep sleep isn’t an option. It has to be System On.

      Reply
      1. DARKMAN Avatar
        DARKMAN

        aha 🙂
        I’m searching for best available option for hand bracelet strap that would only vibrate on event. By AI, coin battery should last month… I can’t get few hours. Maybe go for STM32?

  2. Stefan Labich Avatar
    Stefan Labich

    Hi Tomas,

    these cheap boards have a lot of parasitic drag. Next to the 4 LEDs – I guess – are 4 mosfets to drive the LEDs. The cheap ones can have quite a bit leakage current. Any cheap LDO is also a suspect for wasting power…

    You need a board with minimal components around the nordic chip…

    Reply
  3. Dave Avatar
    Dave

    I tried out the holyiot nrf54l15 bare module for my matter app. The power draw of the bare module looked pretty good. My matter app hummed along drawing only 6.0-6.75 uA outside of the 5 min active mode interval. This module might be a good alternative for the hobbyist. The 1.27mm pitch castellations and through holes are large enough for home soldering and “dead bugging”. You can also connect a 4 pin pogo pin clamp directly to the module for programming, debug, and serial output. The big drawback is lack of documentation and support as mentioned above.

    Reply
    1. Tomas McGuinness Avatar
      Tomas McGuinness

      Thanks for that.

      I opted for a MinewSemi module in the end. Less pin outs, but easier for me to get onto a PCB thanks to their KiCad support.

      I’m hoping it will have a similar power consumption to the HolyIoT board.

      What Matter project did you use the board for?

      Reply
      1. Dave Avatar
        Dave

        The project is a contact sensor running on a non-rechargable battery. The nordic online power profiler estimates an average current consumption 6.0 µA. The sleep current is running about a 1uA above the estimate of 3.1uA. I plan to spend a little time to optimize, however, the current power consumption is probably good enough.

      2. Tomas McGuinness Avatar
        Tomas McGuinness

        It’s pretty amazing how energy efficient these Nordic devices are!

        I’m hoping my module and my PCB will hit 12 months of battery life.

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