ESS limited feedin to grid causes smart chargers to toggle mode

Dear Community,

i have following setup:

Multiplus 5000
2x Smart Solar Charger 250/65
620 Ah Hoppecke OpSZ 48V
Venus GX on Raspberry Pi 3
10kWp PV.

I am running ESS mode with feedin of excess Energy to the grid when the battery is full.
After the last firmware update of all components 2 weeks ago, even the limitation of feedin power seems to work. Due to the single phase connection i would like to limit the feeding to for e.g. 2kW.

The Problem:

When my battery SOC is at 100% and feedin is limited, the solar chargers toggle from absorbtion to bulk operation quite quickly (within seconds). This leads to pulsing power between roughly 0 Watts to 1600Watts to the battery, allthough it should be kept in float voltage and roughly steady 60 Watts. Also the voltage rises to ~56V for seconds. The power of the chargers also varies from 0 Watt to 1200W.

It seems the ESS System tries to reach the feedin limit but the controller oscillates very strong.

When I disable the feedin limitation, the chargers run steady up to the availlable solar power.

I was wondering if I can adjust settings of the controller or somehow prevent the smart chargers from toggling operation modes.

Help is much apprechiated, as I think the pulsing power to the charged battery is not beneficial for battery lifetime and also for the electronic components.

Thanks in advance,

mathis

2 |3000

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matejs commented · May 02, 2021 at 06:45 AM

I have exactly the same problem. Smart 150/35 with 1.56 firmware (older versions of firmware also have this problem; I hoped 1.56 would fix this).

Note: it happened today, I switched to "Optimizing self-consumption" for a couple of seconds and back to "Keep battery charged" to get the system out of this state.

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