Major issues with my first build!

[Delta Star]

Hi everyone! I'm not sure where else to turn. I've tried and tried to figure this out, but I'm getting nowhere. I have a few different issues, so I'll try to paint the whole picture at once. Here is what I am trying to put together:

Important components:

Frame: Scorpion Y650 (Y6, carbon fiber and aluminum)
Motors: NTM Prop Drive 28-30s (20a, 800KV)
ESC: Turnigy Plush 30a
FC: HKpilot 2.5, running Arducopter 3.0.1

Other things I don't THINK matter:
Using a Turnigy 9X with er9X, FrSky w/ telemetry, Xbee telemetry for Mission Planner, and I've added LED lights.

Now, everything WAS working great. I was using 5000mah, 25C Turnigy lipos. It was a *little* under powered, in that it was hovering at midstick and I still mean to add a Go Pro, so I was mildly concerned, but for the moment flying perfectly.

The first thing I noticed was that on all 4 of my lipos, flight duration was only a few minutes, and for some reason the cells were discharging unevenly. I am using an Accucell 6, and always charge at 1C and always in balance mode. When I say the cells were uneven, I mean like 3.5amp, 2.2amp, 1.9amp. That kind of range.

So I read up on it and decided I probably got a bad batch of batteries. Someone, somewhere, recommended SMC lipos. I found one that is 5100mah, 4S, and 40C discharge. Sounded a little more powerful, so I got that.

That's when everything fell apart. I added my LED's and Xbee telemetry at the same time. I don't THINK that has anything to do with my problems, though. What started happening, was that it would drift to the right or backwards (randomly one or the other... not both). It's as if the trim is way off, but so far off that trim can't fix it, and it's not consistent anyway.

I suspected Arducopter, so I played with a lot of settings, but nothing helped. I decided to temporarily invert the ESC leads at the FC. Sending my left motors the data from the right ones, and vice versa. The copter *STILL* wandered either to the right or backward, in stabilize and acro modes.

So I deduced it wasn't likely Arducopter's or the FC's fault. I switched the motors on the left with the ones on the right, and then the problem did shift from one side to the other. Now the copter drifts to the left or backwards, randomly. Sounds simple enough - probably faulty motors... but they're all brand new, pretty much, and why is it such a random result?

I noticed that my new battery also dischargde unevenly, but not as bad at first. It ranged like 3.4a, 3.4a, 3.6a, 3.7a. Until I let it completely drain by accident. After cheating a little to get it charged, now it discharges *totally* unevenly, allowing 2 cells to drop to 1amp and the other two stay at 4.7a. Is this battery toast now? Is there something wrong with my charger or my copter causing all these battery problems?

I read that the props I'm supposed to use aren't the 10x4.5 ones I have, but actually should be 11x7. Should I switch to those bigger props?

Should I get 6 totally different motors? Or just replace a few suspect ones? Should I try yet another battery type? 3S, or 4S?

What would you do?

 

[Stacky]

I had drifting problems a year or 2 ago which sounded exactly like your and it turned out to be the Turnigy radio rx. Are you able to try someone elses radio and rx to eliminate that as the cause?

 

[PeteDee]

The props should be okay, I am using the same motors on a 550 hex frame and using GemFan 10x4.7 props using 2x 2200mh 30C 3S packs, I am getting around six minutes but the packs are fine afterwards.

As far as the drifting sounds like a setup/calibration thing to me, even if the motors were off a little from each other the FCU should compensate. Have you done a calibration on your ESC's?

Pete

 

[Delta Star]

Thanks guys,

I don't think it's the radio, since I can see the output in Mission Planner, and it seems reliable. Also, everything was fine before switching to a 3S... nothing on the radio was changed, and since I'm using a power module for the FC, it is also being fed the same voltage. Oh, and flipping the motors around wouldn't cause the problem to move over if it was the radio. But the short answer is no, the only other radio I have is a Walkera.

PeteDee, it sounds like you're running everything exactly as I am, except with 3S. I think I need to switch back to that. Have you tried 4S? I have calibrated my ESCs over and over, in every possible way. I don't think they can be the cause. Really starting to think it's the motors, but I don't know what could have happened to them.

Also very frustrated about the uneven discharge... Anyone ever had a problem with the Accucell 6 charger?

 

[soler]

Hi Delta,

When you mention your battery I presume the figures you are talking about at Volts and not Amps? If you have drained your battery down to 1 volt then I suspect this will give uneven discharge results. I would recommend a small Lipo alarm that plugs into the balanced charge connector, that way you will hear when the Lipos are low and you need to land.

For the drifting issue It is very strange that after swapping your connections round to the FC that you were still able to fly. I had one issue with APM where I used a MAC running windows in VMware to update the firmware, when updating it gave a small warming message at the end but seamed to work as expected when connected to mission planner. However the flight characteristics were terrible. Once I reloaded the FM from a true windows machine everything was working well. This may not be related to you but really caught me out for a long time.

 

[PeteDee]

Thanks guys,

I don't think it's the radio, since I can see the output in Mission Planner, and it seems reliable. Also, everything was fine before switching to a 3S... nothing on the radio was changed, and since I'm using a power module for the FC, it is also being fed the same voltage. Oh, and flipping the motors around wouldn't cause the problem to move over if it was the radio. But the short answer is no, the only other radio I have is a Walkera.

PeteDee, it sounds like you're running everything exactly as I am, except with 3S. I think I need to switch back to that. Have you tried 4S? I have calibrated my ESCs over and over, in every possible way. I don't think they can be the cause. Really starting to think it's the motors, but I don't know what could have happened to them.

Also very frustrated about the uneven discharge... Anyone ever had a problem with the Accucell 6 charger?

As far as the discharge you should only be running the packs down to around 20% of capacity, grab your self a LiPo pack tester, I use a Hyperion EOS Sentry.

If you are not sure how long you can fly for just do a few minutes and land and check your pack, then do a minute or two more depending how much is left, generally around 3.8 volts per cell is discharged to 20%, any more than this and you will damage cells.

I have an Accucell 6 and an iCharger 206B, both work about the same except that the 206B will charge at a much higher rate and has some really nice cycling modes.

I am pretty sure that my 550 will run fine on 4S but I would have to drop off my lights, I run my TBS Discovery on 4S and it is fine with the same type controller but better ESC's with Simon-K firmware.

Cheers

Pete

 

[Delta Star]

Thanks guys... I do have a voltage alarm that shows each cell. I wasn't aware that I should only go down to 3.8V. That's terrible - I've been flying WAY beyond that. Today, I decided to put back one of the 3S batteries, and it's still drifting backward. Did I damage something permanently? I'm going to order more motors and try replacing one at a time until I isolate the bad motors. Also have a question about motors, but I'm gonna put that in a different thread

 

[PeteDee]

As far as the drifting is concerned it is pretty normal in any mode other than in GPS controlled mode to have some amount of drift, even if it is very still there will still be some air movement. If it is in GPS mode and it is still drifting part of your calibration is not quite right. I am not familiar with the FCU that you are using so can't give specifics.

Pete

 

[soler]

You do not mention is our specs that you have GPS, if you do are you sure that you are getting a good GPS Fix before take off. Also check you centre of gravity, and ensure your FC is level.

 

[Delta Star]

You do not mention is our specs that you have GPS, if you do are you sure that you are getting a good GPS Fix before take off. Also check you centre of gravity, and ensure your FC is level.

Thanks Soler,

Yes, I have GPS, but not flying in a mode that uses it yet. I thought of CG, but since the only changes since flying properly have been very light items, I don't think that's the propble, FC is perfectly level, and also hasn't changed since performance changed.

 

[soler]

Try flying in a Loiter mode to see if that stops the drift. I would say this is normal unless it is flying off fast.

Also in arducopter there is a way to set up trims on the transmitter and then save these using a switch on the transmitter. There is a YouTube clip showing you how to do this.

 

[Stacky]

Seeing the output in the mission planner wont show you a problem with the radio rx inside your multirotor. The initial problem you have described sounds exactly like the one I had. It turned out to be the radio rx. it probably isnt but I think you really need to try another radio to eliminate that as the reason. Thinking it isnt the problem doesnt eliminate it as a possible source. I have had 2 Turnigy 9x radios, converted to the er9x firmware and both had drifting problems. I have never had that problem again after at least 20 builds with my Futaba radio. The trouble with these problems is working out what is the problem. Elimination of possible causes is the fastest way to find a solution. Borrow someones radio and see if you still have the problem.
My problem would take 30 seconds or so to show up so any mission planner isnt going to show rx drift

 

[Delta Star]

Thanks, but I think that switching the motors from left to right, and observing that the problem actually moved with the motors, proves that the radio rx isn't the source, at least for my issue. I'm looking for a problem that's either inherent in the motors, or something else that caused damage to the motors which may or may not still be present. I can't see have the rx could have damaged the motors. I think that since I switched to 4S immediately before the problem started, is a clue of some sort, but as yet I can't figure it out.

Seeing the output in the mission planner wont show you a problem with the radio rx inside your multirotor. The initial problem you have described sounds exactly like the one I had. It turned out to be the radio rx. it probably isnt but I think you really need to try another radio to eliminate that as the reason. Thinking it isnt the problem doesnt eliminate it as a possible source. I have had 2 Turnigy 9x radios, converted to the er9x firmware and both had drifting problems. I have never had that problem again after at least 20 builds with my Futaba radio. The trouble with these problems is working out what is the problem. Elimination of possible causes is the fastest way to find a solution. Borrow someones radio and see if you still have the problem.
My problem would take 30 seconds or so to show up so any mission planner isnt going to show rx drift