I have the power module, but the voltage of the battery keeps going up and down non stop. Every second its different. One second 11 volts, the other 10.6, the other 11.1 and so on. My quad did 2 landings because of low battery when i have set it to 3.5/cell and the voltage was 3.75. But because of the up and downs it decided to land. Why is that?