Calculating kWh from an AC current logger

How to calculate Kilo-Watt-Hours (kWh) from an AC Current Logger, SR3 logger

The information you require to do this is the logger’s sample rate and the voltage. Now, do the following: (in TrendReader for Windows)

1. Graph the file of information and zoom in on the period you wish to determine the KWH for.

2. Enter the following custom equation under EQUATION, NEW EQUATION:

The above equation assumes the voltage is 120V. If it is something other than 120, substitute the correct voltage where 120 is.

3. After the equation has been written, select FILE, SAVE and make a note of the equation number.

4. Now apply the custom equation to the graph by selecting EQUATIONS, ADD COMPOUND LINE TO GRAPH, and enter the equation number from step 3 and press the Enter (or Return) key. You will then have the following menu appear:

5. Click your mouse once on Source0, and then on AC Current #1. Then click your mouse on Source9 and then on Constant. You will now have a new menu box appear, prompting you for the value of the constant as in below:

6. Enter the logger’s sample rate in minutes. Then select OK and then select ACCEPT. You will now have a graph of the KWH as shown below:

To determine the total KWH, move your mouse to the far right hand side of the KWH line, or view the Graph Statistics and look up the “High” value for the KWH line.