Arduino Pro Mini with AA batteries

[ottawahacker]

@jremington

You should be able to do a lot better than 4 mA in sleep mode. When using deep sleep with the watchdog timer to wake, current consumption is typically < 7 microamps, or about 500x reduced.

You were totally right. I tested couple arduino boards and couple nrf24 radios and I found the issue... For my sleep loop I had

    LowPower.idle(SLEEP_8S, ADC_OFF, TIMER2_OFF, TIMER1_OFF, TIMER0_OFF,
                  SPI_OFF, USART0_OFF, TWI_OFF);

This takes ~3-5 mA but changing it to
LowPower.powerDown(SLEEP_8S, ADC_OFF, BOD_OFF);
drops my power usage in sleep mode to 0.01 mA