The way I'm thinking of involves writing down the current draw of the system every min and then multiply this number with 3600 to get the current draw for one whole day. For now I've only tried to calculate the current draw when the station is not sending data, as I want to make sure it's correct before I proceed to when the station is transmitting.

I know the following current draws of the components:

Datalogger CR1000X: 1mA

PTB100: 8,3mA (Runs for 3 seconds every 10th second)

AT/RH: 4,5mA (Runs for 1 second every 10th second)

Modem idle use: 0,9mA

My first assumption is that the stated currents from the datasheets, are expressed in mA per second. (As Ampere is defined as charge pr. second)

With this knowledge I've made the following excel sheet to get an overview of the current draws during 1 min of operation.

I sum up the currents to get the usage per min.

Multiply the sum with 60 to get mA/h

Divide with 1000 to get A/h

And multiply with 24 to get amps drawn per day.

If all of the above is correct, does this mean that a 72Ah lead acid battery would supply the station with power for:

72/16,428 = 4,4 hours

My personal guess would be that my assumption about current being measured per second (from the datasheet) and the calculation of current drawn per hours is not correct.

What am asking is if this is the right way to do it?

Thank you.