Buzzer problem, batterie low

I´m using an APM 2.8 and the buzzer starts beeping too early to warn me of too low voltaje in the batterie. It starts at 11,5 V, is there any way to change this value? Someone with a similar problem?
Thanks!!

Juan,

look at the documentation for failsafe - it is described there: http://ardupilot.org/copter/docs/failsafe-battery.html

You can set it to 10.5V in the field on the setup screen easily, should fix your issue.

It assumes of course that your power sensor(that measures the voltage) is setup correctly of course.

Cheers,
Christian