Puck.js as power meter logger - how do you keep track of pulses per hour and day?

I have another reading that shows current watts based on time between the pulses.
But I wanted to keep track of the total pulses for the day and actual kW use per hour. But for this I need to know when the current hour or day is over

Does the time sync happen during the code upload? Guess it would break then when doing battery replacement