nPM1300-EK + NRF5 SDK: Is It Possible?

RE: nPM1300-EK + NRF5 SDK: Is It Possible?

Simonr — Mon, 12 Aug 2024 13:36:33 GMT

Glad you were able to make something work on your end. In the nrf_fuel_gauge process, the t_delta parameter refers to the time difference since the previous processed measurement.

t_delta should reflect the actual time delta from the previous call to nrf_fuel_gauge_process(). However, the algorithm will consider the current consumption in between calls to nrf_fuel_gauge_process() to be an average between the two. If t_delta is large due to the system being in an idle state, it is better to use nrf_fuel_gauge_idle_set() function prior to entering the idle period. The next time nrf_fuel_gauge_process() is called, use the actual t_delta as normal.

Also note that t_delta is a floating point value, so it would have to be very large for anything to start overflowing.

Best regards,

Simon

RE: nPM1300-EK + NRF5 SDK: Is It Possible?

J0sh1101 — Mon, 12 Aug 2024 08:03:16 GMT

Hi Simon,

Thanks for the answer. I manage to make it work.( For anyone doing the same.)

To make it work you need to include:

- add the nrf_fuel_gauge.h header to your project, which is located in the zephyr drivers.

- Tell the linker to include the library libnrf_fuel_gauge.a into your build, which is located at nrfxliby\nrf_fuel_gauge.

- Add the battery model to your project, you can get it from nPM PowerUP.

- Include the library like this:

    static const struct battery_model battery_model = {
        #include "battery_model.inc"
    };    
    
    uint32_t err_code;
    struct nrf_fuel_gauge_init_parameters parameters = {
          .model = &battery_model,
          .opt_params = NULL,
    };
    
    
    /* Store charge nominal and termination current, needed for ttf calculation */
    max_charge_current = 0.15; 
    term_charge_current = max_charge_current / 10.f;
    
    /* update the fuel gauge values */
    parameters.v0 = bms_end_data.voltage;
    parameters.i0 = bms_end_data.current;
    parameters.t0 = bms_end_data.temp;
    nrf_fuel_gauge_init(&parameters, NULL);

- Call feul_gauge_process() to get the state of charge (SOC):

  uint32_t err_code;

  // read the bms parameters
  err_code = drv_bms_read_data();
  VERIFY_SUCCESS(err_code);


  delta_in_s = ((float)app_timer_cnt_diff_compute(app_timer_cnt_get(),ticks_latest_delta) / (float)TICKS_IN_ONE_SECOND);
  ticks_latest_delta = app_timer_cnt_get();


  static float soc = nrf_fuel_gauge_process(bms_end_data.voltage, bms_end_data.current, bms_end_data.temp, delta_in_s, NULL);

  return NRF_SUCCESS;

What I don't understand is the delta_in_s. Is this representing the time that has elapsed between SOC measurements or is it just how fast I measure to use this delta for some other estimation?

If I would go to low power for say 2 days then the delta_in_s would be very large as the SOC wouldn't be triggered, then I could get an overflow which would create an error in the estimate, right?

RE: nPM1300-EK + NRF5 SDK: Is It Possible?

Simonr — Tue, 23 Jul 2024 08:41:47 GMT

No, the nRF5 SDK does not support the nPM1300 EK by default, but it is possible to implement on your own, but you will be on your own in doing so. Here is a non-zephyr example that supports bare metal operation: https://github.com/NordicSemiconductor/npmx-zephyr/tree/main/samples/fuel_gauge Note that this example uses Zephyr as a wrapper, but since the function calls all are independent of the Zephyr framework, it should be pretty straight-forward to port somewhere else.

Best of luck and regards,

Simon

RE: nPM1300-EK + NRF5 SDK: Is It Possible?

Michal — Wed, 17 Jul 2024 22:03:35 GMT

Hello,

I will check this internally and I'll get back to you.

Best regards,

Michal