3DR power module problems

I have got this sensor and is attached to my battery , everything seems to work but I Arducopter didnt stop to use the power and now my battery is lower ( 5volts).
I did some research and I found a old guide saying to check FS_BATT_ENABLE that is 1 ( enable ), it wasnt!

Does Arducopter really cut the power if I arm the drone or spin motors when the voltage is low?

My configuration:
Monitor 4
Sensor 4
APM ver apm 2.5+ 3dr power module
Battery 4200 mah

I wont to throw away another battery so I want to make sure that it will not happen again

Here is a link to using the 3DR Power Module: copter.ardupilot.com/wiki/common … -with-apm/
This wiki might help you to understand how the PM in relation to the Fail Safe Function.

:black_medium_small_square:You can also individually power each servo from each individual ESC-BEC. :black_medium_small_square:Simply run the power and ground from each ESC-BEC individually and directly to each servo. (Very handy for multicopters).