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mihair asked

ESS system, very noisy System Grid and AC out when MPPT is in OFF state

Hi guys,

My AC coupled ESS system has a small MPPT 150/35 (750W PV power) connected on DC bus, a 230V 5000/48V Multi, a Solarmax 6000S (4.8kW PV power) connected on AC IN and a CAN REC-BMS with 22 kWh LFP battery. Every component are running the latest firmware versions.

Both grid metters on main AC input and output of Solarmax are RS485-MODBUS Carlo Gavazzi EM111 and are connected to RPI running latest stable Venus OS via isolated RS485 industrial USB interface

Everything work well except over the night when System Grid and AC OUT (Critical Loads) become very noisy (please see picture below)

The MPPT DC cables are below 1m long with 16mm2 section. Multi DC cables are below 2m long, 70mm2

Anyone have any idea about the root cause of this behaviour? Could be from the fact that MPPT is connected directly to secondary Multi DC pols and not to the battery?


Thank you very much,

Mihai


@Guy Stewart (Victron Energy Staff) @mvader (Victron Energy Staff)

ESS
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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

Could you isolate the load appliances that are connected and see if that makes any difference?


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mihair avatar image mihair Guy Stewart (Victron Community Manager) ♦♦ commented ·

First of all, thank you for your quick answer!

Being a vacation home, there are very small loads permanently connected on critical AC-OUT side; fridge, WIFI and alarm system

Few days ago I had done a test with grid disconnected (Multi in Inverter mode) and graphs are very smooth. As a side note, in this state the overall 24H power consumption of the house is smaller than when the system is connected to the grid (1,2kWh from the grid plus 0,8 kWh from DC versus 1.2 kWh from DC only)


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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

I have moved this to the modifications space as it is running on Raspberry Pi.

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mihair answered ·

Hi @Guy Stewart (Victron Energy Staff) @mvader (Victron Energy Staff)


After some more tests setting ignore AC-IN-1 ON and OFF by using Multi relay assistant, general flag and Generator manual start in CCGX I have come the following conclusions:

1. The noise is much lower, almost non existent when no AC (main) is allowed to get into the system

2. The system is consuming much more power when AC is allowed to enter.

3. The noise is not related with the AC loads - not an intrinsic factor of them.

Any idea why the system is behaving like that?

In the picture below one can see how the system works with or without AC-IN-1, ignored till 10:20 hours and allowed to enter after.

Thanks,

Mihai




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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

Is this running a CCGX or raspberry pi?

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