For the case we are talking about of (BT fault), I found through event history that a repetition of a series of the same messages:
Battery charging OK, date... time...
Battery test fail, date..., time...
Battery charging OK, date... time...
Battery test fail, date..., time...
Battery charging OK, date... time...
Battery test fail, date..., time...
Battery charging OK, date... time...
Battery test fail, date..., time...
But this has no thing to do with device's batteries...! rather it was panels fault: BT...
Obviously, when tried to test the panel batteries with a battery tester, the battery tester didn't come on at all..., blank display..., batteries totaly dead, and once replaced them by brand new ones, and pressed silence and reset, nothing happened, tried the system reset option several times, nothing happened..., the (BT fault) didn't clear from the display, I guessed that due to the processor reported the (battery faulty) for so many times, it classified it as permanent fault, and stopped testing the batteries..., threfore it needs then a proper reset which is called (warm start with EMS 5000 panel), otherwise I have to wait for I don't know how long, to get it cleared out from the display... etc