Data crunching questions - why?!

JTimbood · Post by **JTimbood** » Tue May 13, 2025 4:43 pm

Hi there,

We have a new installation comprising 8 panels run through 2 inverters (as on FiT) and with a 5kW battery. All is running well however, I am struggling to understand some of the data the app is presenting us, and was hoping you may be able to help

1) Why does there appear to be a relationship between PV generation and load, when one goes up the other follows, etc? I didn't expect to see this. I have attached a few screen shots. Is it something to do with inverter arrangement?

2) Why do I appear to be exporting more than I am generating (no additional generating sources)? The daily stats show me generating producing more than exporting (for example PV production = 20.20kwh, 7.10 to Load&Battery and 13.10 to grid). But the graphical display shows export > generation for example 4.33 kW export against 3.1 kW generation (see attachment).

3) For Load - the graphical data shows it being consistently quite high (say 1.2 KW) but then dropping when I put on a high load appliance. You can see this in attachment where the little blips are when the induction hob went on.

Any idea what is going on?

Thanks so much

Post by **Dave Foster** » Tue May 13, 2025 5:45 pm

Can you provide a bit more information about the existing system, you mention 2 inverters - is the FiT inverter handling the solar 8 panels and the Fox system running as a battery storage device - or does the Fox system also have solar panels attached?.

JTimbood · Post by **JTimbood** » Tue May 13, 2025 6:18 pm

Hi there. The FiT inverter (fox) handles about 4 panels I think, then second inverter (fox) handles the rest and has fox battery. I can only think that the two systems aren't talking to each other properly in the app when looking at real time. But end of day stats look correct.

Sorry, I only have basic understanding of the set up but can try to find out more from installer if needed

Post by **Dave Foster** » Tue May 13, 2025 8:18 pm

What you can see from the traces as you say the load increases with PV, but the load should be in the opposite phase i.e. under the line that is because the battery inverter (hybrid) is seeing the export from the other inverter as negative load.

In a setup like this you should have a second CT clamp wired (CT2) from the hybrid inverter and clamped around the live output of the solar only inverter - it then knows how much is being exported and it can calculate the correct load and also be able to effectively use that export.

JTimbood · Post by **JTimbood** » Tue May 13, 2025 8:38 pm

Yes, that sounds like the fix. Thanks very much, I'll contact the installers And hopefully sort something with them.

JTimbood · Post by **JTimbood** » Tue May 13, 2025 8:46 pm

Sorry Dave, last question, why does the front screen on the app (showing the house and energy flow) show the right numbers and the daily summaries seem right, but the real-time graphs show wrong? And I guess the issue is mainly within the app and not actually affecting how the system operates?

Should I be looking to get this sorted as part of the initial install rather than additional work?

Thanks for the advice,

James

Post by **Dave Foster** » Tue May 13, 2025 9:57 pm

The app will be doing some reconciliation as it has both inverters in the account but the real time graphs are coming from the data produced by the hybrid and because it can’t measure the amount of power from the solar inverter it is getting all of it’s maths wrong.