Battery charging

My battery have not been charging at all (stay at 0% all the time) since 9 Dec but excess electricity has been exported to the grid. I wonder if there is any problem with the battery or its settings. The amount of power exported since early December is less than 2.4kWh per day.

Doesn't seem correct - what does the portal say you system is operating in?

As anglefire says, we need a bit more information (or pictures from the Portal/App) to help you identify the problem.

For example, in the App, do you see a voltage for the battery?