The solar battery also powers some loads in the house via the inverter. The battery current will be positive when charging and negative when discharging to the loads.
The fridge, oil heating / hot water and some lighting is included in the loads. The inverter will automatically switch off when the state of charge drops to around 40% and those loads will instead be powered by the grid until the state of charge reaches 100% again.
This is to ensure that there is always a good state of charge available for these loads in the event of a power failure.
The webserver always runs from the solar battery as this is not powered via the inverter.