This is the xev ouput when pressing the fn+f3 battery hotkey:
MappingNotify event, serial 39, synthetic NO, window 0x0, request MappingKeyboard, first_keycode 8, count 248
FocusOut event, serial 39, synthetic NO, window 0x3e00001, mode NotifyGrab, detail NotifyAncestor
FocusIn event, serial 40, synthetic NO, window 0x3e00001, mode NotifyUngrab, detail NotifyAncestor
KeymapNotify event, serial 40, synthetic NO, window 0x0, keys: 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
This is the xev ouput when pressing the fn+f3 battery hotkey:
MappingNotify event, serial 39, synthetic NO, window 0x0,
request MappingKeyboard, first_keycode 8, count 248
FocusOut event, serial 39, synthetic NO, window 0x3e00001,
mode NotifyGrab, detail NotifyAncestor
FocusIn event, serial 40, synthetic NO, window 0x3e00001,
mode NotifyUngrab, detail NotifyAncestor
KeymapNotify event, serial 40, synthetic NO, window 0x0,
keys: 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0