Trimming and voltage protection issue

[saidquad]

DJI-wkm and x650 v4.

1. In Atti. Mode I have to trim the rudder and elevator in order to achieve level flight. In GPS Atti. The quad flies level when all trims are in middle position. The problem is when I put all trims in middle position and fly in GPS Atti. Mode, and suddenly the GPS signal is lost in the middle of flight, WKM enters Atti mode automatically and I lose control because it is not trimmed.
2. In WKM software, voltage monitor section I turn the protection switch to ON. I use 3 cell lipo. First I calibrate then I put the first level protection to 10.5 V and the second level protection to 9.6 V (loss 0 V for both). And I push write button. The quad descents when the red light warning starts to blink. After landing I check the voltage of the lipo and it is always around 11 V. Hence I get very short flight time (about three minutes with 5850 3 cell lipo).

Any suggestions?

 

[Mihnea de Vries]

Suggestion for part 2.

First: 10.5V means 3.5V per cell. That's a little low for First level protection. I suggest about 3.6-3.7V per cell for firs level protection. For second level i suggest to not go lower than 3.3V per cell because you might damage the Lipo pack.
Second: Put around 0.3V Line Loss, and try again. After you land, measure again, if the voltage is still higher than you wanted, increment with more 0.1V until you find the correct line loss and get the end voltage you want. But i think, if the Lipo is in god condition, your line loss must be around 0.3V for a 3S pack. Usually this is about 0.1 volt per cell with a new Lipo and it will increase in time when the battery will be old.

Line loss is the difference between voltage of your LIPO when you fly and the Lipo is LOADED (meaning there is a current load on the battery) and the voltage measured when the Lipo is disconnected from your copter, and there is NO LOAD on the pack. You can measure the LOADED voltage by strapping the copter to your table and measure the voltage while motors running and stick is at 50%. Be very carefully if you do it this way, propellers can eas cut your fingers off!

 

[Mihnea de Vries]

Another suggestion would be to put just one question per thread, in this way the thread will not be mixed with two problems and easier for everybody to read.

About your question 1.
I don't understand why you use trimmers? you should not use trimmers at all for hoovering (as you call it, level flight) Also is weird to lose the GPS signal on the fly if you are outdoor. Are you flying indoor?

 

[EgonW3]

Ad. 1. I have Futaba 9C. I've connected it to Wookong Assistant, calibrated and with trimmers in neutral position calibrated each channel using end points and sub-trims, so with sticks in their central position all sliders in Wooong Assistant are exactly in their center position and green, and when sticks are in min or max position, sliders are in their max or min position also. This way of configuring Tx gave me very stable PH with hands off the sticks.

 

[saidquad]

Mihnea and EgonW3
Thank you for your suggestions. I will follow your instructions and hope for some improvements.