I’ve been using Victron ESS for quite a long time now (since around version 3.60), and I need to be honest — this issue with MPPT throttling has been present for a long time and still isn’t properly resolved. My setup is not unusual: AC-coupled inverter (Fronius) + Victron MPPT + battery. The prob…

Hi, I would like to share a final update regarding the issue. After a detailed inspection, I decided to redo the entire DC side to eliminate any potential weak points. The following changes were made: all MC4 connectors were replaced with original Stäubli EVO2 and properly crimped MC4 Y connect…

I’m also having something like this with my RS6000 on 3.70. Now starting to notice it as there is more sun during the day. During the sunny periods, Phase 1 is throttled while a few kW is imported from the grid. This doesn’t make any sense? For now, i’m shutting off DESS during the day. This will c…

I am seeing exactly the same behaviour. MPPT is being limited while there is still available solar power, and sometimes even when the battery is not full. This definitely does not look like correct ESS behaviour.

I have exactly the same issue as you. During sunny conditions, MPPT is being limited or even drops to 0W while the battery is not full and solar power is available. This does not make sense and looks like incorrect ESS behaviour.

The dash indicates PV inverter on AC input though.

The Fronius is intentionally connected on AC IN due to feed-in tariff (green bonus), so it must run continuously. However, this should not cause MPPT to drop to 0W while: Battery is only around 50–60% Solar power is clearly available No settings are being changed Also, I observe that the system …

[image] Oldrich: The Fronius is intentionally connected on AC IN due to feed-in tariff (green bonus), so it must run continuously. However, this should not cause MPPT to drop to 0W Indeed but it is why I asked about AC PV on the Input and you replied it was on AC OUT. You might want to refe…

[image] Oldrich: During sunny conditions, MPPT is being limited or even drops to 0W I had a quick look at your data – I assume you observed this today – and with the exception of two times when it looks like you rebooted the GX (around 11:30 and 14:00), the MPPT seems to be tracking a maximum…

[image] versendaal: I’m also having something like this with my RS6000 on 3.70 As a side node, yes, this happenes for the RS along with DESS in a few situations. Fix is completed, scheduled to go into a 3.80 for a while, then also ported to a 3.7x release. (All VEBus Systems and Standalone …

Thank you for checking my data. However, what I am observing is not just a small MPPT rescan. The power drop is very significant – sometimes MPPT goes from around 4–5 kW down to near 0W, and then recovers again. This happens while: Battery is only around 50–60% Plenty of solar power is availabl…

Thank you for your explanation. I understand that MPPT periodically rescans for a new maximum power point. However, in my case the drop is very large (from ~4–5 kW down to near 0W), which seems too extreme for a normal rescan. Also, this behaviour repeats multiple times during the day, not just o…

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

DIY

nickdb (Nick) 1 April 2026 12:48 10

Indeed but it is why I asked about AC PV on the Input and you replied it was on AC OUT.

You might want to refer to this topic as it might be related.

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

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