- 2,541
- 2,090
- 113
- Location
- Efland, NC
I'd like to add that we may not always be able to monitor every circuit in a panel to measure load. Even if we can't, meaningful info can be determined from a usage trend from the main lugs on a panel. I've included a screenshot of the output of the inverter here at home. My emergency loads panel is powered via a Schnider hybrid inverter. As long as I have enough sun to keep the batteries charged, the system does not draw any utility power.
In the trend below you can see that the computers powered by the system draw a relatively constant ~200w. The small square bump on the trend is a chest freezer. The larger square bump is the fridge. The largest square bump is the fridge doing a defrost cycle. After the defrost cycle you can see an extended compressor run cycle to recover from the defrost. Most devices draw a pretty constant current when on. This makes identifying which "bump" on the graph belongs to what device pretty simple.
The point is even if you aren't able to directly measure every branch circuit in a panel, you can still get good data and know what is running and when its running. All you need to do is put a power meter in the right place and capture the data at the right frequency. In the image below you can see that the capture point in the middle of the graph happened to pick up the startup spike of the fridge compressor while the others on the trend did not.
In the trend below you can see that the computers powered by the system draw a relatively constant ~200w. The small square bump on the trend is a chest freezer. The larger square bump is the fridge. The largest square bump is the fridge doing a defrost cycle. After the defrost cycle you can see an extended compressor run cycle to recover from the defrost. Most devices draw a pretty constant current when on. This makes identifying which "bump" on the graph belongs to what device pretty simple.
The point is even if you aren't able to directly measure every branch circuit in a panel, you can still get good data and know what is running and when its running. All you need to do is put a power meter in the right place and capture the data at the right frequency. In the image below you can see that the capture point in the middle of the graph happened to pick up the startup spike of the fridge compressor while the others on the trend did not.
Last edited:
