I need some multirotor troubleshooting help

[G+_Mr ROKnBOK]

I need some multirotor troubleshooting help....

 

When I quickly increase throttle from <20% to 90%-100% (punch-out) my quadcopter initially responds as expected but (within about a second) acts like it's losing power (with throttle at 90%-100%).

When I switch from a 3s to a 4s battery the problem is more pronounced and happens while I slowly increase throttle starting around 40%.

[see video]

The video shows examples of what I'm trying to explain. On the 3s I'm punching-out. On the 4s I'm starting with slow, fluid throttle-up and holding it in a hover (trying to keep the copter in-frame).

 

I've replaced the ESCs and the motors, as well as the flight controller and PDB, with little success: flight is corrected while using 3s, but no so with a 4s. Batteries are fully charged. All components are soldered, no bullet connections. It's the KH250 build with a carbon-fiber frame.

 

Could bad soldering be a culprit? (I'm no Smitty at soldering)

 

 

Setup:

-RTF MINI-20A (BLUE SERIES) SIMONK

-THE FLIP32+ (V2.6_REV7.)

-RTF MOTOR 2208 - 2300KV ADVANCED SERIES

-MINI POWER DISTRIBUTION BOARD 2OZ COPPER (35X35)

 

[G+_Brian “Yikesfpv” Gipe]

Hmm...interesting problem. What gauge power wire are you using for the battery connector? And what batteries?

[G+_Brian “Yikesfpv” Gipe]

And how are your esc's mounted? If it's too close to the carbon fiber it could be arcing. I learned to use some mounting tape underneath.

[G+_Brian “Yikesfpv” Gipe]

From what I've read and heard, carbon fiber can carry a current. You could have a connection too close.

[G+_Mr ROKnBOK]

Brian Gipe I'm using Zippy 2200mAh 3s 45-90c and Tattu 1300mAh 4s 70c batteries. I've put mounting tape under the ESCs and the PDB. I learned the hard way about the conductivity of carbon fiber – lol.

 

Would arcing cause the issue I'm having? If so I can hunt for other places it could be arcing.

 

Thanks for the reply ?

[G+_Brian “Yikesfpv” Gipe]

Sounds like you've got everything connected good. Check the soldering on your power connectors. Looks like you have 14 or 12 gauge. What OS are you using. Could be some settings in there.

[G+_Mr ROKnBOK]

Brian Gipe yeah, sorry.... Those are 12guage wires to the LiPos

[G+_Stede Bonnett]

It couldn't be something simple like ESC calibration could it? Or the flight controller sending values out of range at the endpoints?

I know it doesn't jive with the voltage difference, but it looks suspiciously like the ESC's freaked out at high throttle.

[G+_Mr ROKnBOK]

Stede Bonnett I agree with you that it looks like the ESCs are freaking out, but I've calibrated them several times using CleanFlight. I've also flashed the FC several times to the last 3 or 4 stable versions of CleanFlight with no improvements.

 

Also...

Today it was suggested to me that I reset the PID settings. I'll try that tomorrow after work and report back.

[G+_Brian “Yikesfpv” Gipe]

I've done that before. Switching out parts and nothing works and then it turns out it was some stupid setting. lol

[G+_Mr ROKnBOK]

UPDATE:

I've checked that there are no wires shorting to the frame. Reset PID settings. No improvements :(

 

I held the quad in my hand and gave it full throttle (with 4s batt) and noticed 2 of the motors would lose power at full throttle. Then one of those motors died along with the ESC. (Switching out the ESC, and then the motor, was my path to that conclusion.)

 

Next I will replace the other 3 ESCs and test.

 

FWIW: I've been working on the RasPi Security Cam project (due to several recent break-ins in my neighborhood) which has been stealing time from the quad fix.

[G+_Mr ROKnBOK]

UPDATE 2:

 

I replaced the burnt out motor and the ESC it was attached to, and left the other three ESCs as is. The quad copter still had low thrust, but it did not fly erratically any longer. I put brand-new propellers on and the quad copter regained its thrust. The ESC I replaced the old one with now seems to not respond the same as the other three ESCs. It is as if the new ESC has a max that is lower than the other three. I'll re-calibrate all of them and report back.

 

The final note: it seems that a bad motor and ESC combo were the initial problem with my erratic flight.

[G+_Brian “Yikesfpv” Gipe]

Awesome! Hope it works out. Let us know.

[G+_Mr ROKnBOK]

UPDATE 2.1:

Flying great using the 3s batteries, but still having the same problem as earlier using the 4s. I'm gonna get some air-time (read: practice) for a while before going after the problems I have using 4s batteries.

[G+_Mr ROKnBOK]

FINAL UPDATE:

The quad is flying great now.

 

I removed the fauxPro case and started flying with 2-blade props (5x4.5) which greatly improved flight performance. An ESC got fried when sand grains prevented a motor from spinning. After replacing the ESC the quad couldn't lift off the ground with the 2-blade props (for whatever reason), so I switched back to the 3-blade props (5x4.5x3) and the quad flew great.

 

Bottom line:

Seems as if too much weight was my biggest problem. It may have been compounded by some poor soldering (I re-soldered every connection at one point; found some questionable connections). The biggest improvement came after reducing weight.

I've also tested out this lighter setup using a 4s battery with good results. I didn't push it too hard with the 4s (every previous 4s attempt ended with a fried ESC or two). The only problem I had was that the quad wanted to lift off at idle (I've started flying in "air mode" so the motors spin-up as soon as the quad is armed). That's the kind of problem I can live with, lol.

 

Thanks, again, to everyone who took the time to help me out with ideas and direction.

[G+_Brian “Yikesfpv” Gipe]

Glad you got it working, man!

[G+_Mr ROKnBOK]

Thanks, Brian Gipe, me too.

next area of focus: PIDs