we can interject our ideas all day.
how many times a second does the data get logged ? that would yield answers about memory size and such
and would or should branch off into discussions about not recording data that is in the expected tolerance. why bother data logging a hour of 230 volts of 6.125 amps when you really want to know when the amps went from 2.1 to 6.1 and when they dropped again ?
household, to me, means single phase, ergo, only needs to monitor one sine wave. that is running at 60hZ or 50hZ ?
and you have to have about 4 times the data points in order to know where you are, so figure 256 points a second ? how many seconds in a month ? or, do you calculate voltage and show RMS ? and amps, and time ?
or, was the thought about using I2C or SPI and data storeage and dumping in conjunction with writing the display ?
or, just maybe, the question was if the attached SD socket is addressable by the Arduino ?
as in is the SD socket addressable by the Arduino ?
sort of "is it read only, or read and write and is it only for use by the display..."