Inverter limiting PV generation?

[PeeVee29]

Hi all,

I recently had a solar plus battery system installed as follows:

15kW Inverter - H3-15.0-Smart
42kWH Battery - EQ4800
14 x 490W Solar panels

I have noticed however that the amount of PV energy generated seems to be varying significantly day by day, and not at all correlated with the sunshine. As an example, across two sunny days I had 14kWh of production on one and 33kWh on the other.

Looking further into the data on the app, it appears that two of my "strings" (apologies if this isn't the right term, I'm still something of a newbie here) are being periodically disabled. Note that this doesn't appear to be correlated to sunlight whatsoever, all the panels are in around the same place and direction facing, I regularly see them not functioning when the sun is directly overhead as well.

Here's an example where the 3 strings appear to be active most of the day. PV3 is always active, PV1 comes on around 8am, PV2 comes on around 10am. All 3 are generating through to dusk.

The previous day however, PV2 switches on at 12pm and PV1 at around 1pm

I also have some days where only PV3 switches on

And some where the other strings get switched off intraday.

The switching off of the strings is somewhat correlated with generation exceeding consumption and the battery getting full, although it tends to lag. It's also frustrating as I should be fine to export excess power generated.
My suspicion is that there is some kind of software logic in the inverter which is limiting generation, potentially due to it not thinking that exporting is possible (Although I have the export limit set to 10kW).

I can't seem to find any settings to keep all of my strings on though. Would appreciate it if anyone has any clue as to what is going on and what I can do to fix it?

[MaterialBarracuda48]

I cannot answer everything for you, but you have in theory plenty of capability with your 15kW H3 to mop up all of the solar you can produce 14x490W = 6.86 kWp of potential power.

You show a graph for PV3 that was the only string that activated, and showed a normal hump curve, and you would expect the 3 strings to show a similar output given your capacity.


I am wondering if you have a hardware fault on those strings?
Your settings are wrong in the import/export values? (though you state export is set at 10kW)
Your firmware needs updating and checking settings afterwards?
Are you running the system in some odd work mode/schedule running?
Have you given some external control over to 3rd party to control your system (Amber in Australia for example)

[PeeVee29]

Thanks so much for your response.
To answer your questions:
I have contacted the installer to check if there is a fault on those strings. It feels less likely that it is hardware fault though as when PV1 and PV2 are active, they generate along a similar curve to PV3. I'm no expert though.
My settings (below) are pretty standard I think. Although potentially I read that the export limit can be overridden on the installer's end.

Software I believe is up to date (screenshot below as well)

System is only being run in self use mode, haven't played around with anyone else.
I haven't given external control to any third party, planning on signing up to Amber or GloBird. I am still waiting on getting a Smart Meter installed at the property, so maybe the lack of smart meter is an issue?

[MaterialBarracuda48]

You may have to go to the Inverter screen and look at the system settings, to check Import/Export and battery values for the Current and Power.

I do see the Import power is set to 0W not seen that before.
There are a few videos on Wills Youtube channel that can help you check these values
https://www.youtube.com/@iameccles/videos

A few direct videos lined up here in this recent post viewtopic.php?p=13019#p13019


The lack of smart meter won't affect your Fox gear, as it only uses a CT Clamp to measure the power flowing. It is blind to what meter you have fitted.

[PeeVee29]

I've checked those settings and everything looks normal to me (same as on those videos). Have set the import limit above 0W now, although I don't expect much impact from that. I'm still kind of at square one although potentially the installer will be able to better illuminate what is going on.
Thanks again for your help!

[MaterialBarracuda48]

Well good luck with the installer, there might be some hidden value (from and End User account PoV) that they can adjust to change the system behavior.

If still stuck either post back, or reach out to Fox support as they can look at your system remotely and identify issues via their systems.