Does anyone know where the measurement is derrived for the Phantom2 v2 battery level before it's relayed over the Mini iOSD?

In trying to sort out why my Phantom randomly looses so much thrust, I wondered if perhaps there's a fault in the battery connection where it's incapable of delivering required current while still indicating an adequate battery level if it's measuered internally in the battery and then relayed through a seperate conection?

It may be a completely different issue altogether so I'm putting your battery question aside for the moment.  Please provide some more specifics about how those random losses of thrust manifests themselves.  For example; will it maintain a steady hover, does it suddenly drift off in one direction, does it suddenly lose altitude and then recover?  When you connect to the Phantom Assistant are the IMU readings moving in and out of tolerance?

gil Posted at 2015-10-7 03:21
It may be a completely different issue altogether so I'm putting your battery question aside for the ...

It's a uniform loss of thrust so there is no drift or rotation.

If there was a chance for recovery after loosing altitude there was never enough altitude for the "fall" to allow time enough for thrust to return enough to either stave off impact or to even give an auditory cue that thrust had returned. (generally events have been closer to the ground, first time I wrote about in this thread)
first post in that thread has video.

Full throttle input on the controller only mildly slows the descent.

When connected to the Phantom Assistant, IMU and controller readings are normal and stable within respective ranges.

Granted I've not continually monitored the IMU for random failures for more than 5 min, nor do I understand the internal workings well enough to gauge likelihood of physical motion randomly initiating a fault.

After each impact, at least for a minimal stretch of time after repairing impact related damage as necessary, it's capable of flying without issue. After the first event, there was about a dozen flights, including an immediate relaunch to assess status, which was a normal flight for ~10min.  The next event(#2) was during my systems checks immediately after launch. (systems obviously were not ok) After that event there was only one full flight which I did in my front yard without issue in an attempt to figure out possible cause.

Without  any further indications of problems from that flight I had convinced myself that I must have missed a sudden rotor effect given the terrain during event #2 and that event #1 had been long enough ago that it was genuinely a random glitch. However almost two weeks ago during event #3 there was enough altitude to dismiss any possible terrain related causes, in addition to time of day precluding thermal activity, and calm winds up to 20k so winds aloft weren't remotely related.

Thank you for any help or insight! I've not found anyone else on the entire internet who has dealt with this issue.

Glitch Posted at 2015-10-8 01:49
It's a uniform loss of thrust so there is no drift or rotation.

If there was a chance for recovery ...

To your question in the OP regarding the Battery level.  Information originates from the Battery internal circuit and is transferred via the smartbus cerial communication ports on the battery.

I kind of doubt that your issue is related to the battery and looks more like an IMU or ESC fault that causes  the sudden lift loss.

consider using one of the 3rd party apps like ultraflight  by kenargo so you get full log og all telemetry like batt voltage - then you can see real time afterwards what is happening.....

PanamonCreel Posted at 2015-10-7 12:19
To your question in the OP regarding the Battery level.  Information originates from the Battery i ...

Thank you for the confirmation about battery level status communication.

Unless there's something I'm missing I don't know how it could possibly be an ESC issue as it's uniform, so all four ESC would have to randomly fault simultaneously in the same manner.

As for the IMU, I'm still at a loss because the faults are random, however as I don't understand the operation I can't hypothesize further. For it to be the IMU it would have to sustain an error where it perceived steady rapid vertical movement and what I'm seeing is the compensatory drastic throttle reduction.

Likely my rationale for this not being a hardware failure of the IMU is that I've not found anyone else on the internet who has experienced this same issue. Although the same logical fallacy applies to battery connection issues I expect my Phantom has a poorly shaped battery compartment where since it's arrival I've needed to slam the batteries into the Phantom for them to seat (reminiscent of the Brue Lee inch punch), and then an intense test of finger strength to remove the batteries where the tabs are merely decorative when compared to the extreme friction holding the battery in. (This is true for both batteries I fly with, and neither are swollen)

yorlik Posted at 2015-10-7 17:25
consider using one of the 3rd party apps like ultraflight  by kenargo so you get full log og all tel ...

I'm guessing this is in reference to the vision and not the regular P2? The only interface with an app that I know of is my GoPro WiFi app which I don't use so as to not interfere with either the 5.8 video Tx feed or the 2.4 Phantom controller freq.