I am posting this on behalf of wscherp above.... he is the owner of the quad but we frequently fly together.....
So I decided to document this a little more here in this thread because the quad is a Phantom 2 N.V.
So far we've had 2 complete power loss issues while flying with this "knockoff" battery. Both were in good flying conditions and under very tame flight conditions. I'm pretty sure both were while filming, I know for sure the second one was and I'm going to see if he (the owner) will let me edit them together and share them here.
The long and short is that for no known reason power completely shuts off, no visual low battery warning from the copter as far as LED pattern flashes or anything. I have seen it go into the first low power routine on one flight where I was flying it with the DJI battery.... No problems encountered on that flight.
The last power loss that happened, there was closer to 50% battery life left according to the assistant software and the LED's on the third party battery.
Inspecting the battery's stat's in the assistant software today did reveal something odd.... I shows battery life expectancy still at 100% and that it's discharge cycles are at zero. This battery has been used a number of times and should show some degradation.
The DJI battery reflects it's use properly. 97% life and 12 discharge cycles. The "knockoff" should reflect slightly less but similar stats.
Also while connected to the computer today, the suspicious battery caused the "Non DJI Battery" window to pop up and disappear quickly 2 times. It didn't stay, but we were able to read it before it went away. This happened with about 33% charge left on the battery.
Regarding the posts we've read about the DJI firmware blocking third party batteries with certain Phantom 2 behavior or indicator light patterns etc ... We have not seen this at all. The lights and routines of the quad behave exactly the same as with the DJI battery. Both on firmware version 2 and after we updated to version 3 recently.
We haven't removed the top of the body to check for loose connections but today with the third party battery installed I did tap and thump on it and the quad while connected to the computer to see if any shorts or power spikes or anything unusual was noticeable on the battery gauges and there was nothing out of the ordinary.
He and I suspect that maybe the mfg of this battery has found a way to fake the quad into seeing it as a real battery and in doing so some of the protections of a genuine battery are bypassed and or disabled. We're just guessing of course but have planned to do some testing to see if we can glean any more information. Both for our peace of mind and to benefit the community. We certainly don't intend to fly over anything populated and or risky with the third party battery and are even a little suspicious of the quad itself seeing as how all instances we;ve found here of sudden power loss had the original DJI battery installed. That part just makes it more confusing.