Any way I can change it so the buzzer will go off with less then half the pack left.
Once the BATT parameters are all calibrated and set properly, http://ardupilot.org/copter/docs/parameters.html#batt-parameters
You can set FailSafe parameters http://ardupilot.org/copter/docs/parameters.html#fs-batt-voltage-failsafe-battery-voltage
Set FS_BATT_VOLTAGE to say 10.8 for a 3 cell Lipo battery (3.6 volts per cell) - adjusting this will determine when the buzzer and LED indicate a failsafe.
You’d also need battery capacity set in the BATT params, BATT_CAPACITY. Set this to the normal capacity of your battery, example:2000 mAh
Ideally you’d also set the milliamp hours failsafe value, FS_BATT_MAH , assuming you always use the same battery or batteries of the same capacity.
Set FS_BATT_MAH for 80% of you battery capacity used:
example: 2000mAh battery, 20% remaining = 400mAh (put 400 into FS_BATT_MAH parameter)
Best thing to do is set all that up correctly and accurately, and either have:
- telemetry so you can remotely see the voltage and current values somehow
- or get an external voltage alarm that plugs into your balance leads and set it conservatively, say 3.7 volts , to allow you plenty of time to decide where to land.
Edit: fixed up wording and flow for better clarity (I think…)