Save only maximum value per day

Setup, Configuration and Use Beginners
5

I do something similar for my PV system.

I have an item that represents the current power output of my solar PV: Solar_AC_Power. This gets stored into influxdb persistence on every change.

Then I have a rule in jruby:

rule 'Update max solar power' do
  changed Solar_AC_Power
  run do
    midnight = ZonedDateTime.now.truncatedTo(ChronoUnit::DAYS)
    midnight = midnight.minusDays(1) if TimeOfDay.now < '4am'
    max_since = Solar_AC_Power.maximum_since(midnight, :influxdb)
    Solar_AC_Power_Max.update max_since
    Solar_AC_Power_MaxTime.update max_since.timestamp
  end
end

You could do this without using persistence if you prefer, simply by comparing the current value vs the new value, e.g.

  midnight = ZonedDateTime.now.truncatedTo(ChronoUnit::DAYS)
  if Solar_AC_Power_MaxTime.is_before(midnight)
    # You could save the previous day's max value here if you want to
    Solar_AC_Power_Max.update 0 # Reset this for the new day
  end

  if Solar_AC_Power > Solar_AC_Power_Max
    Solar_AC_Power_Max.update Solar_AC_Power
    Solar_AC_Power_MaxTime.update Time.now # You could use ZoneDateTime.now if you prefer typing it
  end