I was reading an article someone modified an arduino and is running in low power mode.
An Arduino Uno runs less than one day on a 9 V battery because it uses about 45 mA current. Using an Arduino Pro Mini, with a simple modification, the power consumption goes down to 54 μA (0.054 mA) with the 3.3 V version or 23 μA (0.023 mA) with the 5 V version, in power-down sleep. That is 4 years on a 9 V battery with 1,200 mAh capacity or 2,000 times more efficient than the Arduino Uno. After removing the voltage regulator, the power consumption is only 4.5 μA for the 3.3 V version and 5.8 μA for the 5 V version, in power-down sleep.
He claims he can run the arduino (obviously it is doing nothing) for 4 years. Ignoring leakage and other things aside, how can I do the math to verify this claim?