Sudden solar panel output drop off @ noon everyday

[StuBoston]

Any ideas would be very appreciated. For context my solar system is completely off grid. The stats are as follows:

Solar panels: 7S2P, 260V nominal, 4KW. I have 2 sets of these for a total of 8KW nominal.
Inverter: SunGoldPower SP6548 with 390V max MPPT per input (there's 2 inputs) I only have 120v output
Batteries: Bank of 48V, 30KWH, LifePo4.

This is feeding a 2,000 sq ft house with typical house usage for a small family.

So here's my question: For some reason every day EXACTLY at noon my solar production drops from over 6KW to under 1KW. There are no trees or shadows blocking any of the panels, my batteries are at different states of charge every day, and my inverter is only a few months old and just started doing this. Over temp is not the issue because the outside temp is ~70° and in the garage where the inverter and batteries are is also ~70°. I can't figure out why the solar input drops to less than 1KW every day EXACTLY at noon. It's been doing this for about 3 weeks now. Any ideas?

 

[zanydroid]

Probably your battery filled at 12pm. If there’s nowhere for the power to go the SCC will stop making the juices

Quick test is to fire up a big appliance and see what happens. Hair dryer or clothes dryer

 

[StuBoston]

Probably your battery filled at 12pm. If there’s nowhere for the power to go the SCC will stop making the juices

Quick test is to fire up a big appliance and see what happens. Hair dryer or clothes dryer

That was my initial thought but it drops every day EXACTLY at noon. And my batteries SOC is different every day based on which nights we use the washing machine, dishwasher, mini split, and EV charger, etc.

 

[zanydroid]

What’s the SOC when it stops? Maybe the charge controller is confused, busted, or parameters are off.

Still worth testing the response to a load.

 

[MisterSandals]

Inverter: SunGoldPower SP6548

Are there any time of day settings? Does it switch to utility first at 12:00 for example?

 

[StuBoston]

I actually don't know the SOC of the batteries @ noon because I'm usually not home. I could try asking my wife to put a heavy load on the inverter for an hour or so sometime after noon to see if that alters the solar production numbers. Thanks for the input!

MisterSandals, the inverter doesn't have any time-of-day priority settings. I wish it did but it's not that "smart". It's basically the same inverter as a LV6548.

 

[Balrog006]

What settings does it have if any?

Can you look up its software update log and see if it did a download that coincides with the start of the issue? Perhaps it’s a software glitch in an update.

 

[#40Fan]

I actually don't know the SOC of the batteries @ noon because I'm usually not home. I could try asking my wife to put a heavy load on the inverter for an hour or so sometime after noon to see if that alters the solar production numbers. Thanks for the input!

MisterSandals, the inverter doesn't have any time-of-day priority settings. I wish it did but it's not that "smart". It's basically the same inverter as a LV6548.

Plenty of timer settings that are available in the LV6548.

 

[zanydroid]

Try changing the time on the unit and see if it moves by the time shift?

 

[StuBoston]

Try changing the time on the unit and see if it moves by the time shift?

I just changed the time ahead a few hours to see if anything changes. Thanks!