Discussions

Hello, 

I have a problem about my new-build f450 quad and asking for your help. 
First things first; let me write my setup;

*Frame : DJI F450
*Flight Controller: DJI Naza V2
*ESC: Dalrc Engine 4in1 40A
*Motors: Sunnysky V2806 (650KV)
*Battery: ZOP Power 4S 6300mah 35C
*Props: 1240 Carbon Props

Here is my problem;
When I fully charged my 4S Lipo battery to maximum; It hovers and flies without a problem for first couple of minutes. After a little bit voltage reduce (maybe 0.5V) it starts to tilting & drifting & losing stability. This problem gets bigger if I continue to fly, and about 3-4 minutes later drone can not stand stable and crash. Then right after that, if I plug in another fully charged battery; it flies again for 1-2 minutes, and after that it happens again and again and again. 
If I plug half-charged battery, it never flies stable.

My notes:
Esc's are calibrated well. 
Motors & props easilly turn, no tightens,
Emi shilding is okay with copper tape.
Gains are default DJI naza gains (maybe I need to change it a bit)
Motors, esc, naza is stay cold during flight (no overheat)
Setup also been tested on ecalc many many times, ecalc says everything is working okay, also it should fly about 20-21mins hover

I have suspicions about a faulty ESC but it flies for 1-2 minutes well. Problem occures after that.
I have also suspicions about a fake C rate on battery; but a "hovering" dont use a lot of current, it can not even hover stable after 2-3 mins flight.

So I can not solve this problem. Could you please help me?

Thank you.