ESS throttling MPPT without valid reason (AC + DC system, battery not full, reproducible

DIY
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21

Thank you for your explanation.

In my case, the behaviour seems much more extreme than a normal rescan. As you can see in the attached video, the MPPT power drops very close to 0W even though solar conditions are stable.

This does not look like a typical short rescan that lasts only a few seconds.

Also, this behaviour happens more often, not just at long intervals like every 30 minutes.

Could this indicate a possible issue in the MPPT firmware or some specific interaction in my setup (ESS + Fronius + battery)?

I am happy to provide more data or run additional tests if needed.

22

Hi @Oldrich77 , I added some additional monitoring on my side to see if we can catch enough data to diagnose this. Now we wait for data.

23

Thank you, I appreciate it.

I will continue monitoring the system and provide timestamps and additional data if I observe another drop.

24

I think we already have something to work with. You are right. You can see the rescan squigles on this chart, plus that one time where it completely drops out.

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The Multi is lowering the charge voltage. Let me look into this some more. This is not the first time I’ve seen something like this, but it is the first time I’ve seen it where there is no PV-inverters involved.

25

Thank you for your analysis, I really appreciate you looking into this and working on it.

I will keep the system running as is and continue monitoring.

I fully trust that your team will get this resolved, and I am glad I could help identify a problem that is not easy to detect.

26

Just to let you know, I have updated the system to the latest beta version (3.80.14).

I will continue monitoring and will report any changes in behaviour.

27

This might be simpler than we thought.

Your site did this again today around 10:33AM. Data logging says the reason for the outage is no input power. Check your PV wiring, it might be as simple as a loose connection.

28

Thank you for the suggestion.

I will check all PV wiring and connections to make sure everything is secure.

However, the behaviour seems very fast and the power returns immediately, which made me think it might not be a physical connection issue.

I will verify and report back.

29

Just a quick update – I checked and retightened all PV connections at the MPPT, as well as all DC and AC protections.

I will keep monitoring.

30

The issue occurred again today at 10:31.

All PV connections have been checked and tightened, so it seems unlikely to be a wiring issue.