Need to reduce power consumption when powered by VIN pin.

I'm running the MKR NB 1500 with 5 V on the VIN pin and attempting to reduce power consumption. There is a topic "MKR NB1500 High Power Consumption" which get's consumption down to around 1 mA using a LiPo battery. The steps there are:

  1. All non-usable GPIO pins set to INPUT PULLUP: Apply pinMode(gpio_no, INPUT_PULLUP); for each gpio_no.

  2. Disable the status LED: digitalWrite(6, LOW);

  3. Use LowPower.deepSleep(TIME_IN_MS); to put the module to sleep

I've implemented 3 and 4 and powering off the modem with power consumption about 13 mA. I'm somewhat old and dense and to me it's not clear as to what the 'non usable' GPIO pins are so haven't added that yet, but think there are other issues. The green led by the USB connector is on (USB cable not connected) and the charging LED is flashing (no LiPo battery is connected). Anyone have any suggestions on how to reduce the consumption when running from VIN? I would be reasonably happy with 1 mA while in deepSleep, of course less would be better.

I removed the power LED and deep sleep consumption dropped to 8 to 9 mA. I set the Analog pins to pinMode(A0, INPUT_PULLUP); and the consumption is 7 to 8 mA. Maybe there's a regulator or something consuming some number of mA.

Sometimes I'm pretty dense and realized I'm measuring the current between the battery and the power module so wasn't observing the current draw of the MKR1500. Today I've moved the meter between the power module and VIN and am observing 1 to 2 mA (my meter only measures ma) when in deep sleep. I was measuring the consumption going into the Pololu 5V Step-Up/Step-Down module S18V20F5 which according to the graph should be 80 - 90 percent with the voltages and currents of my setup. So the power module is going to be the major current consumer when in deep sleep mode.

After some time or some event the charge light starts flashing. Don't know what triggers it. In some post there was a mention that this might occur but it wasn't clear to me as to what to do about it. The power consumption increases from 1 to 2 mA to 5 to 6 mA when the led statts flashing. Anyone know how one could turn this off or prevent it from happining?

Do you have a link to "MKR NB 1500"?

OK. I found it. No battery detected after about 20 minutes. Thanks. Now pursuing how to disable this behavior if it’s possible.

Looking at the data sheet for the bg24195l I find:
When a fault occurs, the charger device sends out INT and keeps the fault state in REG09 until the host reads
the fault register. Before the host reads REG09 and all the faults are cleared, the charger device would not send
any INT upon new faults. In order to read the current fault status, the host has to read REG09 two times
consecutively. The 1
st reads fault register status from the last read and the 2nd reads the current fault register

Does anyone know if reading and clearing REG09 will stop the charge LED from blinking?

This topic talks about the causes of the flashing charge LED: