FillLevel of Battery

> The fill level of the storage asset as a percentage of its capacity
If ESDL file is self-contained, then this does not make sense. Fill level is state at a point in time.

It could mean Initial Fill Level (at commissioning date, eg.).
If it means initial fill level at start of simulation run, then we need some more information on a simulation run. I'll make a different issue of that. :)