I have problem with my quad. I bought a WLtoys V686G FPV quad. And it has been flying fine for a few months now.. I also bought an extra battery. I took it for a flight over the weekend and there was a sudden loss of power. I assumed this to be a battery problem. After inserting a fully charged battery it had no power to take off. it would just hover 1 - 2 feet off the ground. I tried both of the the batteries and still had the same problem. I also reset the gyro, to make sure it was balanced. Also calibrated the x and y axis's individually and still have the same issue. I tried the batteries in another quad of mine and the batteries are 100 %. Any ideas on how i could perhaps fix this or what else i could look at?