The Aeon Energy Readers have the ability to read power in watts and also kWh. I’ve set up two of these and the Watt readings seem appropriate. However, the kWh readings are always very low. For instance, I have one meter which reads Watts from a solar array and this will show readings up to about 2000 watts during the day. However, the kWh readings are always about 50 kWh.
The kWh should be the sum of the power over time. I don’t know how (or if) the meter is summing the power readings to come up with kWh. I’d like to know kWh per day but don’t know how to get the Energy Reader (or OpenHAB) to do that.
50 kWh = 50,000 Wh
50,000 Wh / 24 = 2083 W per hour for a day
Seems about right given the information you have provided.
Which specific reader do you have? I would guess that the kWh channel is providing the kW used in the past 24 hours. I’ve a reader but it has a channel that just keeps on counting up until you send it a command to go back to zero. Without knowing what device you have and what channels are available I couldn’t guess the best way to get or calculate the information you want out of the device.
I use these meters too (DSB09). The meter internally sums the kWh, so the difference of values is the kWh value used/produced since the last report. The kWh storage can be manually reset, but it is also reset when the meter is removed/included in the network. I find that sometimes the meters can be a little flaky, and the reports either don’t come in, are off by a factor of 10, etc. For my most sensitive readings, I have items for raw data and items for refined data that have been massaged in a rule to make sure the data is valid. Here are some options (but they are basically the same thing):
- Set the meter to report kWh daily, then setup an item and rule to be the difference between the current kWh value and the previous one. This is a simple one, but also a single point of failure.
- Use persistence and do a 24 difference in the kWh values. Basically the same as 1, but you have more values to look at in case there is a gap or bad values. You could also sum your power readings and divide by the total time to do a sanity check on the kWh readings, but that’s a bit of overkill.
Your array should be putting out about 10 kWh per day (2kW per hour), so if your readings are always around 50kWh, then something does not add up. Unless you have the more expensive model meter that reads flow in both directions, and you have it hooked up to your mains so that it would stay (hopefully!) at a pretty constant value.
Thanks for the suggestions.
I have the Aeon DSB09 meters.
This is the graph I am getting:
You can see the yellow graph of Watts and the blue graph of kWh which does not change much.
Not sure what it is reporting for kWh. I would think it would continually increase until reset.
Not sure how to set it to report kWh daily.
Well, it is continually increasing, at least in that screenshot. Because you are using two vastly different scales, that little increase in the blue line actually equates to roughly 10000 Wh. That is a big difference.
Don’t forget that 1 kWh is 1000 Wh so showing them both on the same chart is misleading at best. So, if both values were of the same scale, that value you currently have a little before noon on the chart for watts at around 1000 W would actually be 1 if both values were using the same scale. Alternatively, if you adjusted your kWh to Wh the blue line would be around 40000, not the current 40.
Without using something like Grafana where you can have two Y-axis ranges it really does not make sense to chart both of these on the same chart. Their scale and absolute values are so far apart that if you normalize the values (i.e. only use kW or only W) it ends up suppressing the actual changes in values of one of the two measurements.
Ughh! Duhhh! You’re right! That’s the problem.
One is kWh and the other is watts.
I need to scale one of them to keep them on the same chart but that doesn’t seem possible.
I guess I’ll just have separate charts.
It’s possible to have a secondary axis in HABpanel, which is exactly what I use to plot my Aeon energy monitors.
Looks like I have to define a group to get it to display another axis.
I’ll fiddle with it.