I've gone through 3 of the BetaFPV 1s only whoop boards and 3 of their 1-2s boards and all of them have issues with the accelerometer and angle mode. They all have an exponential drift when in angle mode. The longer they are armed the worse the drift gets. I've been looking around the net trying to find info on this and I've seen where this seems to be common but I haven't found a solution. 

Can anyone make a suggestion? the 1s boards are installed in cockroach frames with the soft mounts that come with the boards and using BetaFPV 19500kv 0802 motors and new props. I've tried different props from Gemfan and HQ. The 1-2s boards have been in 75mm and 85mm BetaFPV frames as well as 100mm carbon fiber frames. I've tried tuning and switching to Betaflight 4.0, 4.1 and 3.5.7. In 3.5.7 I tried the setting Oscar suggests in his blog and that seemed to help some but the issue just slows down a bit. It never goes away.

Nothing seems to help this problem. All of the boards fly fine in Acro mode. 

BTW, I have tried calibrating the accelerometer and trimming using stick commands. But, this doesn't help. Also, I have noticed that in Betaflight setup tab the model will drift slowly without the quad actually being moved.

Thanks for any suggestions or help.

Are your midpoints on your radio 1500? Maybe you need more deadband?

Does the slow drift 3D model also happens when the radio is turned off?

(14-Jan-2020, 05:23 PM)voodoo614 Wrote: Are your midpoints on your radio 1500? Maybe you need more deadband?

Does the slow drift 3D model also happens when the radio is turned off?

Yes, the slow drift in Betaflight happens with or without the transmitter connected. My rc deadband is set at 3 and so is the Yaw deadband. I checked my midpoints on the radio as well as in betaflight and have set my end points in betaflight. Same settings on all the BetaFPV boards. All my D16 models are bound under the same model on the transmitter.

BTW, the radio is Frsky X9D with newish hall gimbals.

My other whoops (Inductrix, BetaLite, Newbeedrone Lite and Hummingbird) do fine in angle mode with the same radio. The Newbeedrone Lite is even bound under the same model in the transmitter. The Inductrix and BetaLite are bound to the same radio using the Jumper 4in1 module.

A few other are having the same issue without any real solution.

(15-Jan-2020, 01:32 AM)voodoo614 Wrote: A few other are having the same issue without any real solution.

I may pick up some TinyWhoop 0802's to see if maybe the notchiness of the BetaFPV motors are causing more vibration. I've tried everything else I can think of to rule out vibration issues.

My Lizsrd95 and The Bug exhibit this behavior and I have never figured out what causes it. It really does seem the accelerometer starts to drift until the craft is unflyable in auto leveling modes. Flying in ACRO is fine. It does not seem to be a gyro issue, otherwise I think the problem would be obvious in acro as well.

Wonder if these FC's are using the same accelerometer...?

Oscar had a tutorial to minimize the drift, but apparently some of the settings are no longer available. So it doesn't seem to work anymore.

(15-Jan-2020, 04:21 AM)kaitylynn Wrote: My Lizsrd95 and The Bug exhibit this behavior and I have never figured out what causes it.  It really does seem the accelerometer starts to drift until the craft is unflyable in auto leveling modes.  Flying in ACRO is fine.  It does not seem to be a gyro issue, otherwise I think the problem would be obvious in acro as well.

Wonder if these FC's are using the same accelerometer...?

Yep, I'd imagine so. My larger quads with actual flight stacks don't exhibit this behavior. Neither do the brushed drones.

(15-Jan-2020, 04:24 AM)voodoo614 Wrote: Oscar had a tutorial to minimize the drift, but apparently some of the settings are no longer available. So it doesn't seem to work anymore.

I actually tried Oscar's tutorial by switching the boards to 3.5.7 where those settings are still available. It slowed the drift down a bit but never removed it. I'll probably go back to that version on these boards.

The only quads I have that have become ACRO only are the 20x20 stacks in my Lizard95 and The Bug. All my other quads will fly fine with modes that utilize the accelerometer. The only time I ever use it is when I am messing around LOS.

Both of the ones I have (Eachine MiniCube and HGLRC F4 Micro) have the MPU-6000-SPI. I wonder if there is some way that it is being implemented that is failing...?

(16-Jan-2020, 03:30 AM)kaitylynn Wrote: The only quads I have that have become ACRO only are the 20x20 stacks in my Lizard95 and The Bug.  All my other quads will fly fine with modes that utilize the accelerometer.  The only time I ever use it is when I am messing around LOS.

Both of the ones I have (Eachine MiniCube and HGLRC F4 Micro) have the MPU-6000-SPI.  I wonder if there is some way that it is being implemented that is failing...?

That would make sense. Is that the accelerometer chip?

I have an IFlight whoop board coming to test out as well. Their board actually has Blackbox memory built in. If I get the same issue then at least I might be able to see directly where it is coming from.

FYI, I tried something with my 1s BetaFPV boards that were having problems. I had been running a TBS Pro Unify Nano at 50MW and an AKK Nano VTX at 200MW on these two flight controllers. I had been powering the VTX's from the 5v source intended for this. I am using these higher power transmitters because I needed the extra transmitting power due to a lot of interference in my house and neighborhood. But, I was wondering why the 1s boards were having issues with Angle mode when the 2s boards were not. So, I tried running the VTX's power source straight from the 1s battery. The accelerometer issues seem to be resolved. At least I hope. I'll keep flying them for a few days to make sure the problem doesn't come back.

My guess is that these VTX's were drawing enough power from the 5v source on the board that they must have been affecting the rest of the electronics. Who would have thought?