Hi i am expanding my system by adding another inverter and a load of panels, i have a Type 1 installation and the current inverter is hanging off an emonTx, i would like to add another CT to the emonTx to monitor the new inverter, how should i modify the following code? also adding a Tesla PowerWall, can i monitor this also? again same question applies. cheers
Type 1 System Setup
For automatic MySolarPV App setup use the suggested feed names mendtioned below in bold. These names are case sensitive.
The following assumes:
CT1 (power 1) = site consumption.
CT2 (power 2) = solar generation.
Setup site-consumption Feed
Click on spanner icon to configure emonPi/power1.
Add the following process steps under Add process:
Log to feed, called use, with feed engine PHPFINA, at 10s interval.
Power to kWh, called use_kwh, with feed engine PHPFINA, at 10s interval.
input, choosing power2:. This will subtract the solar generation from the current value, giving us what’s being imported.
Allow positive. This will allow only positive values to pass, since import is only if this number is positive.
Log to feed, called import, with feed engine PHPFINA, at 10s interval.
Power to kWh, called import_kwh, with feed engine PHPFINA, at 10s interval.
Setup Solar PV Generation Feed
Click on spanner icon to configure emonPi/power2.
Add the following process steps under Add process:
Log to feed, called solar, with feed engine PHPFINA, at 10s interval.
Power to kWh, called solar_kwh, with feed engine PHPFINA, at 10s interval.
Once complete click on Apps > MySolarPV in order to launch the MySolarPV Emoncms app, If you decide to use custom feed names the app will give you the option to select your solar, use and import feeds.
I don’t know MySolarPV, so I cannot tell you what needs to be done there if you want the solar feeds to be shown separately. If you just want the total generation to appear there, then you’ll need to add CT3 (presumably) to CT2 before you do the ‘log to (solar) feed’ step in emonCMS
The emonTx should not need anything doing to it, to handle the second inverter. The data is already being sent to emonCMS as Power3 (and likewise Power4 for the 4th input channel). The only question is the sensitivity of the 4th emonTx input, which is limited to 18.3 A with the standard 100 A c.t. If that is adequate for either the inverter or the Tesla unit, you don’t need to change anything. If the current is more than that, you must reduce the value of the burden resistor for input 4. If you can solder, it’s easy enough to do as it simply means adding a second burden resistor to the pcb. If you say the maximum current involved, we can calculate the value for you.
You will need to sum the PV generations in emoncms as the MySolarPV app only accepts one solar feed and one solar_kwh feed (although the actual names can be changed),
The easiest route is to log the 2 solar inputs as something like solar1 and solar2 and then in the 2nd solar inputs processing add the first and log to “solar” and “solar_kwh”, it’s important to place the summing in the last input of those inputs to update, to ensure you get all the latest values, ie if you sum in the first input, it will use the last value for the second input as it will not have updated to the current value yet.
There is nothing too stop you having more than one MySolarPV app, so you can view each PV array relative to the total use, but you cannot yet see more than one PV input in one instance so totally is required for the whole picture.
As for the Tesla wall, it’s difficult to know exactly how to monitor that without knowing exactly how is connected, but one would assume there will be single connection that charges/discharges so you could use a single CT (if you have another free channel). Once in emoncms you would need to use the allow negative and allow positive processes to separate charge and discharge based on direction alone, much like you would with general import and export calcs.
Currently there is no “battery” app, but there has been some recent development that offered to add battery storage to the MySolarDivert app so it may not be that far away.