How to manually transform pulse to kWh

Hello!

I am trying to obtain the data of the energy consumption of a couple of months ago from the EmonPi and the problem is that it was during the time where I didn’t do a good configuration of the feed.

The result is that now I have an excel sheet with the pulse and the pulse acum. but not the kWh. I would like to know how the EmonPi converts from one thing to the other so maybe I can put the formula in my excel sheet.

I only have values from the optical sensor

Thank you very much for your help!

The answer to that should be on your meter somewhere. each pulse represents a fraction of a kWh, usually it is shown as something like “1000imps/kWh” although there are many formats. Pulses measure units of energy (kWh) it just a matter of scaling and how many pulses = a kWh varies for different meters.

The only thing I know is that 1 pulse equals 1 watt. I don’ t understand how to get the specific consumption of energy in the time of one hour because it only looks like it is increasing and it is definitely not divided in slots of times and then there are other times when there are no values.

I am very confused!

I think I know why you are confused - you have mixed up power and energy.
Power is the rate at which you use energy, or energy is the total amount of power you use over time. The units are different: power is counted in watts, energy is counted in joules, or more usefully watt-hours (Wh or kWh).
So I’m guessing that your meter gives 1 pulse per watt-hour. That means you get 1 pulse after you’ve used 1 watt for 1 hour, or 60 W for only a minute.
So to get the energy consumed over one hour, you count the pulses during that hour.

I think that is “1 pulse equals 1 Watt hour”, there are 1000 Wh in a kWh, so each pulse is 0.001kWh.

The tricky bit with counting pulses is that you do not know what happens between pulses, all you know is that 1Wh was consumed, so calculating an accurate power trace might not be possible when there are long periods on no pulses. ie when a pulse occurs after a long period, was a small amount of energy used at a steady rate since the previous pulse or was there no energy used for a while then a peak of consumption? There is no way of knowing.

If you have pulsecounts and a running total you can get the amount use for any period by one of 2 methods, either subtract the “start time” running total from the “end time” running total, or sum up all the individual pulse counts between the “start time” and “end time”.

Are your pulsecounts done at a regular interval? If they are (for example) 10s intervals you can get an indication of power by multiplying the pulsecount by the fraction of an hour the interval represents ie
pulses x ( 1hour / interval) = average power for that interval, eg 2pulses x ( 3600 / 10 ) = 720Watts. A 720 Watt load ran for 10seconds consuming 2 Wh. to check this math projecting the 2Wh per 10s for 1 hour would be 720Wh, which is equal to a 720w load running for 1hr.