Net Usage/Generation Registers on a Backfed System
In some cases, it can be useful to graph the net flow of power to and from the utility, instead of the total power consumed and produced. This process adds a new view to display this information. The instructions below only apply to backfed PV systems - use these instructions for lineside tap installations.
Note that valid credentials are needed to apply these changes. These instructions also assume that these registers are being added to an existing installation. Steps 6-7 can be skipped on a fresh installation.
2. Set the "Grid" register to record both positive and net values. When done, it should look like this:
Figure 1: Grid register configuration
3. Add two new virtual registers: "Net.Usage" and "Net.Generation". Note the spelling and capitalization must match exactly.
4. Set "Net.Usage" to equal "Grid+" and "Net.Generation" to equal "Grid-". When done, they should look like this:
Figure 2: Virtual register configuration
5. Save and reboot.
6. Once the eGauge comes back online, navigate to Tools -> Split Registers.
7. Select "Grid" and click Start Splitting. This process can take 10-15 minutes - do not reboot the eGauge during this time.
Once the register split process has been completed, data can be viewed on the main graph page by selecting the "Net" view. The images below show a comparison between the default "total used/total generated" graph and the new "net used/net sold" graph.
Figure 3: Default view (note overlapping Usage and Generation lines)
Figure 4: Net view (note power is either moving to or from the utility)