KK2.1.5 Quadcopter Problems

[jwander92]

I am building my first quadcopter using the knuckle kit I ordered from flitetest. Here are the parts I'm using:

4 turnigy multistar 30A ESC's
4 1300kv Blue Wonder Motors
1 2200mah 20C battery
1 kk2.1.5 board

When I power up the motors, they all start to spin. However, eventually, motor 1 will slow and come to a stop. When I bring the throttle back down to idle and try again, motor 1 starts spinning but then it slows and stops again. This has caused quite a few hard crashes because it flies just fine while I am changing the throttle but as soon as I leave it constant, motor 1 slows and stops.

I have tried changing out the motors and ESC's but it always happens to the motor 1 spot so it's not faulty equipment. I have also replaced the kk board and that didn't fix the problem either.

Is there something I need to change that I haven't tried already? I've read that some other people have had similar problems but there has never been a solution given.

Thanks guys.

 

[stay-fun]

Sorry I don't have a solution for you. This is weird! So basically you've swapped out the complete electronics and the issue is still there?! And it happens in flight?

Only thing I could say is, try hooking up only that ESC directly to the throttle channel of your receiver, and spool it up, see what happens...

How does the quad fly otherwise, does it feel locked in or sluggish? If sluggish (too low gains) the motor may stall at some point. I'm running multistars on my tricopter, and when just sitting on the ground this occurs sometimes: the KK board wants to lower the power to that motor because of some input, and once it stalls, it doesn't come back up until I power down completely (disarm and arm) and then start again. But in flight I haven't had any problems.

 

[Balu]

I'm a beginner myself, so I don't have a solution for your, but the common questions seem to be:

- Are you running the stock HK firmware?
- Did you calibrate your ESCs?
- Did you calibrate the KK boards sensors?
- Does the motor spin up when you move the arm down / tilt it towards the motor?

 

[jwander92]

- I have hooked up the esc straight to the receiver and it works just fine.
- I calibrated the esc's using the kk board and individually by plugging them straight into the receiver.
- I have self level off that way the kk board isn't trying to interfere with the motor speed because I just want to get them spinning first.

I believe I have found a solution, however. Because all of my electronics are functioning, I messed with every setting on the kk board until I got a good result. By default, the minimum throttle setting on the kk board is 10%. As soon as I bumped it up to 11% and powered up the motors, motor 1 never slowed and stopped. I haven't had a chance to actually test it in flight yet. I'll update you on how that goes..

I really appreciate the help! I'm new to the forums here.

 

[MattAYSA]

Any progress on this problem? Im also having the same issue with my Tricopter. 3 motors spin up but then one slows down to an idle or stops all together.

 

[jwander92]

MattAYSA ,

Try adjusting your minimum throttle setting on the kk board to greater than 10. That fixed mine.

Jay

 

[CMS_1961]

jwandeer92

I am new to quads too. Built the FT H-QUAD but beefed it up so it will survive crashes--it has!

----Try setting your minimum throttle to 20--that fixed mine (but my problem was not as bad as what you are describing) One motor was just slow to start all the time
----Did you calibrate your ESCs???--- I did not see a procedure on my KK 2.1.5 to do it ,so I did not, but I read elsewhere that if you have motor start issues to perform an ESC calibration, you can find it on YOUTUBE --involves pushing buttons 1 & 4 --
----I am using HK PLUSH 25 AMPs as they are (no special flash)with HK DT 750kva motors and had no issues after setting min throttle to 20??

 

[CMS_1961]

jwandeer92

---One other thought!! I had a hard crash (landed upside down) and one of the bearings in my motor froze up (plus dirt)---that motor acted like what you were describing before I got it cleaned and lubricated and then the motor worked fine again. If you have another motor and can plug it in as a test ---see what happens.

 

[meehan]

MattAYSA ,

Try adjusting your minimum throttle setting on the kk board to greater than 10. That fixed mine.

Jay

I had the exact same problem on my tricopter (also using KK2 board and multistar esc). Bumping up the min throttle fixed it but I am just curious if anyone know why? I am assuming the ESC is going into some sort of shutdown. Anyone have a good idea of exactly why this "fixes" the problem?

 

[Craftydan]

That's a good guess, because it's true.

Min throttle is the absolute minimum "on" throttle signal the kk2 board will send when it's armed and the throttle stick is above that level. Any throttle stick position below that and the ESCs all get an "off" signal. Anytime the throttle stick is above that, if the corrections ask a motor to do less, it stops at the minimum and goes to an idle instead of going below the on/off threshold of the ESC and inadvertently shutting the ESC off . . . which takes time to spin back up . . . all while your airframe is tumbling toward the ground.

If you've got a single ESC that the on/off threshold is *slightly* higher than the others and the min is set too low, you can throttle back and watch that motor shut down early. With the minthrottle set higher than all the ESC's on/off thresholds, they should all spin up at the same time and the should all stay running, until you cut your throttle