The Watt-hour display that I added to my data logger earlier this year has been a real treat to watch.
![Datalogger update 15092-0](https://www.fieldlines.com/index.php?PHPSESSID=00219151be70c6641eb49352b5db8e07&action=dlattach;topic=150486.0;attach=15092;image)
As the numbers counted upward, however, it started to look a little off...
![Datalogger update 15093-1](https://www.fieldlines.com/index.php?PHPSESSID=00219151be70c6641eb49352b5db8e07&action=dlattach;topic=150486.0;attach=15093;image)
That's when I realized I had underestimated just how much energy this turbine will produce, and how big the number will get. While setting up this display item in the datalogger many months ago, I merrily set up the total Watt-hours to add up into the thousands. Shouldn't that be plenty!? Well... no. Now the numbers are overflowing the screen and scrunching out the "Wh" until only the "W" is visible. In a couple of weeks it would tip over >100,000 Whr and then I wouldn't see the unit at all.
Time to face the music and update the logger to show KiloWattHours like it should. Limited space on the screen so I kept it to "kWh" for short. There is space for it to read up to "999.99" before overflowing its place on the screen. Should take a year or two before that happens.
![Datalogger update 15094-2](https://www.fieldlines.com/index.php?PHPSESSID=00219151be70c6641eb49352b5db8e07&action=dlattach;topic=150486.0;attach=15094;image)
While editing the code, I noticed that I had made space for 4 digits on the RPM scale. Umm that implies >1000 RPM which makes for very fast blades! I wonder what I was thinking when I wrote that in the code (it would have been years ago). Trimming down the display units to only 3 digits covers the entire safe range of speeds any WT should have. And it made a bit more space for my sprawling kWhr values.
PS
If anyone is wondering why the 2nd picture says "STOP", that's a little snippet of code that stops the RPM from wandering around in very small values, or getting locked into the last speed measurement before actually stopping, which would leave it reading "12RPM" or something, while the blades are clearly not moving. So anything less than 20 RPM just gets replaced with "STOP".
The OTHER question you might ask about that screen is why the current it "0.1A" when clearly the blades are stopped. My current sensor isn't very accurate, and sensitive to temperature. If I get it zero'ed on a warm day, it's not zero'ed on a cold day.