Modbus write register settings sma battery invertor using service modbus.write_register

Hello all,

I hope this feed is still alive.
I mannaged to get the chargefunctionality by modbus operational.
But something strange is happening.
When my homebattery is charging, exactly every 30min it is deactivated.
I monitor if the battery is charging, deactivate it by modbus when ´not´ and activate it again for max. 30min.

Does anyone know how to change this ´rare´ behavior in the parametersettings somewhere?

Greetings