The power LED on all panels is a status indicator,a flashing power LED means either; the mains power has failed due to a power outage or blown fuse either in the fused spur, or within the control panel.
This means the panel can't charge the battery,or the battery is getting it's charging rate but not holding it,
unfortunately without the correct metering equipment you can't test for mains voltages at the panel or test the battery status,
For your own safety I suggest you get a pro in.
e manno
January 2013