HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 14, 2013, 05:25 PM
Specializing in RC since 1972
Temple, GA, USA
Joined Jun 2009
3,132 Posts
The spec says 5V to 6V. I wouldn't run it outside that range.

Are you running 4S or more? That would probably get pretty hot. I would guess that 3S or less would be OK.

If you are worried about excess heat, you can get a fixed voltage switching (buck) step down regulator on eBay for about $1.60 USD shipped. Step up or variable slightly higher.
theothercliff is online now Find More Posts by theothercliff
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 14, 2013, 05:26 PM
Dreamer
Australia, TAS, Ulverstone
Joined Aug 2004
2,055 Posts
Quote:
Originally Posted by Spinnaker View Post
Does anyone know the minimum voltage the is required to run the KK2 board? I would like to run the board off of a 3.3v UBEC that I have on hand. Any clue if this is sufficent?

I ask because I do not like how warm the ESC that powers the FC is becoming.

Thanks,
Tim
Even though the power demand from the FC is low, it is surprising how much hotter the power feed esc runs ... and if an esc fails, it is usually this one. Have seen this a number of times and I tend to use a uBec these days more and more.
kaz1104 is offline Find More Posts by kaz1104
Reply With Quote
Old Jan 14, 2013, 05:39 PM
5th
Mediocre Pilot Extraordinaire
5th's Avatar
United States, OR, Eugene
Joined Jun 2012
429 Posts
I'm going to ask this despite feeling I know the answer, just so I know I'm on the right track. Plus the KK2.0 experts hang out here.

I have just built a new quad with a KK2.0 FC. On maiden I found it had a bad yaw left and roll right. I have to use about 30 clicks of trim to both yaw and roll on my 8FG to correct and I know this is not the right way to resolve the issue. I am hoping to get confirmation that I have done all I can with the KK2.0 itself to resolve this and that it truly is an issue that must be resolved elsewhere. I have done the following, and the items in blue are those that I believe collectively rule out the KK2.0 as cause (unless it is just plain broken, which I do not believe):
  • I have balanced the props but not the motors. This worked fine in the previous incarnation using the same motors and props. I will balance the motors soon.
  • I zeroed all trims and sub-trims on the TX and did a receiver test in the KK2. A couple of the values were at 4 or 5, so I used a small amount of sub-trim to shift them to 0.
  • I have verified that layout, motor rotation, and prop rotation are correct. Many, many times.
  • I have calibrated the ESCs about 8 times. I have done them individually directly through the receiver and collectively through the KK2. On a side note, I sure wish they used LEDs to signal state instead of beeps. It would be easier to see that all 4 ESCs are doing the same thing. But I digress...
  • I have checked the frame to make sure it is holding the motors straight. It's a modified HK F450 clone, but it's straight. No twisted or warped arms.
  • I did a sensor calibration. I shimmed the landing gear until the tops of the prop adapters were perfectly level in all directions (even diagonally). At that point I checked the FC and it seems to be perfectly level as well. I had modified the center frame some and added an extra plate so it is very rigid. The calibration should be quite accurate.
  • The KK2.0 was working great in x4 mode before I moved it to this frame.
  • All PI settings are the defaults for firmware v1.5, except the pitch/roll P, which was changed to 40, and the pitch/roll I, which is at 0. My testing is with self-leveling turned off.
  • None of the rotors feel "sticky" or hard to turn compared to others. One of them had bearings with too much axial play, so I replaced it, but there was no change to the problem at hand. This was the right-hand unit (+4 quad) and logically the one to be under-performing to produce this behavior, IMO.
  • My battery is immediately under the FC. It has been suggested that magnetic fields or such from the battery or it's wires may be the cause. I have ruled that out by testing with the battery 3" farther down (hanging from the belly of the craft). The ESCs and the harness that connects them to the batteries are about 2" below the FC. I have not tried moving them yet, but considering their current distance from the FC and the common nature of this configuration I doubt they are the issue.

Did I miss anything?

The only thing I have thought of that I haven't tried is a softer mount for the FC, which is currently firmly screwed to a rigid frame. Can motor vibration lead to this behavior?

As stated, I am just trying to be sure I have done everything I can regarding the FC itself. I don't expect assistance beyond that, though I will naturally accept anything offered most gratefully.

Edit: BTW, I can positively confirm that the feature described in #15 of the FAQ in the first post does work as advertised. When the prop cut into my thumb and I released the buttons reflexively the motors cut out immediately.
5th is offline Find More Posts by 5th
Last edited by 5th; Jan 14, 2013 at 06:01 PM.
Reply With Quote
Old Jan 14, 2013, 06:04 PM
Stop me before I build again!
United States, NY, Albany
Joined Sep 2012
1,320 Posts
Motors, props, AUW? Could it be that you just don't have a strong enough set of motors and props for the weight of the copter.
brontide is offline Find More Posts by brontide
Reply With Quote
Old Jan 14, 2013, 06:10 PM
5th
Mediocre Pilot Extraordinaire
5th's Avatar
United States, OR, Eugene
Joined Jun 2012
429 Posts
The motors are Turnigy D2830-11 1000kv and the props are 10" Gemfan. I don't know the all-up weight, but it is an identical list of parts as the last configuration with one added top plate and 8 added nylon stand-offs, and minus the GoPro w/ polycarb case, so it is lighter. The previous config hovered at about 55% throttle. If I use trims to correct it flies fine and hovers at a similar throttle.
5th is offline Find More Posts by 5th
Reply With Quote
Old Jan 14, 2013, 06:14 PM
Stop me before I build again!
United States, NY, Albany
Joined Sep 2012
1,320 Posts
It sounds like motor #1 or 3, so try swapping 1 and 2 to see if the problem follows the motor. Then try swapping the ESC to see if the problem follows the ESC.

Basically start ruling out other bits of hardware.
brontide is offline Find More Posts by brontide
Reply With Quote
Old Jan 14, 2013, 06:23 PM
5th
Mediocre Pilot Extraordinaire
5th's Avatar
United States, OR, Eugene
Joined Jun 2012
429 Posts
Right. Hadn't thought of moving ESCs (doh). Thanks.
5th is offline Find More Posts by 5th
Reply With Quote
Old Jan 14, 2013, 06:25 PM
Registered User
KL,Malaysia
Joined Jun 2008
35 Posts
Quote:
Originally Posted by crampy View Post
Do you have self level on? What settings do you have on that?
I found I had good P and I for my F330, but the self level P gain was too high, causing wobbles. I lowered it to the same level as my pitch and roll P gain and it flies great with self level on and off.

What ESC are you using?
I use SimonK flashed MultiStar 15 amp ESC on it and the reflashed helped out heaps, in regards to allowing much higher settings.
Self level was switched on with SL p-gain,p-limit at 30,30. I've forgotten about these setttings. I assume that kk2 will use this pair of numbers instead of the PI editor figures. Will try lower values to test out this weekend. ESCs are standard 12A HK BlueSeries . I have bought a set of Multistar 15A ESCs also. Wonder whether they're any good without being reflashed .... still waiting for tool to arrive...
kcleong18 is offline Find More Posts by kcleong18
Reply With Quote
Old Jan 14, 2013, 06:32 PM
Stop me before I build again!
United States, NY, Albany
Joined Sep 2012
1,320 Posts
Quote:
Originally Posted by 5th View Post
Right. Hadn't thought of moving ESCs (doh). Thanks.
Another way to spot an underperforming arm is to do a quick throttle up and see which corner droops.
brontide is offline Find More Posts by brontide
Reply With Quote
Old Jan 14, 2013, 11:13 PM
Registered User
jonesy40001's Avatar
Australia, QLD, Meadowbrook
Joined Sep 2012
180 Posts
Quote:
Originally Posted by rexless View Post
Greetings.
I'm searching this forum and google but I'm not finding any details on this. Does anyone know if the KK2 is able to detect and recover from a motor failure, lost propeller, etc.?
In this vid at 2min 50 the quad looses a prop and the descent is ...well kind of controlled. Ok so its a Naza FC but the KK2 is just as capable in AL mode when it is set up correctly. Enjoy.

Prop Fail, Quad Crash, Children and Spektrum/RF basics (8 min 16 sec)
jonesy40001 is offline Find More Posts by jonesy40001
Reply With Quote
Old Jan 14, 2013, 11:26 PM
Specializing in RC since 1972
Temple, GA, USA
Joined Jun 2009
3,132 Posts
Quote:
Originally Posted by 5th View Post
I'm going to ask this despite feeling I know the answer, just so I know I'm on the right track. Plus the KK2.0 experts hang out here.

I have just built a new quad with a KK2.0 FC. On maiden I found it had a bad yaw left and roll right.

...
You get a roll and a yaw. Is there a single motor/ESC that would cause both of those problems if it was underperforming? If so focus on that one.

If you are running 4 of the same ESC's and motors then here are some things to check:
- do you hear the motor RPM oscillating? If so you may have gains too high somewhere.
- are you running the same brand of CW as the CCW props? If not, that would cause yaw issues
- you need to go through the ESC beep menu of each ESC individually (especially the likely arm) and check that the Low Voltage Cutoff battery type is nicad or disabled, the startup type is "normal", or aircraft or fast (not soft, or slow or heli), the brake is off, and the timing (high, med, low) is the same on all ESC's
- I recommend that you check the ESC menus and change just what is needed. Checking tells you what it was. Blindly setting them all the same leaves you guessing.
- you should do all this testing and tuning with Self Leveling turned Off
- when you have the heli trimmed (transmitter trims) with self level off, turn SL on, don't touch the transmitter trims with SL on, instead adjust the ACC trims in the KK2 self level menu.
- if none of this helps, try vibration isolation for the KK2
theothercliff is online now Find More Posts by theothercliff
Reply With Quote
Old Jan 14, 2013, 11:32 PM
Fly Fast, Fly Hard, Fly Fun
rexless's Avatar
Canada, BC
Joined Apr 2012
1,432 Posts
I've watched cheap toy quads descend worse than that and there was nothing broken!
rexless is online now Find More Posts by rexless
RCG Plus Member
Old Jan 14, 2013, 11:40 PM
Registered User
jonesy40001's Avatar
Australia, QLD, Meadowbrook
Joined Sep 2012
180 Posts
Quote:
Originally Posted by kaptondave View Post
Using ACC Trim is the technically correct method and is easier to adjust, especially if both axis need trimming. That is the reason for it being there. Shimming is akin to using duct tape in lieu of a proper repair (IMO).
I strongly dissagree. Any airframe, fixed or rotory wing needs to be "straight and ballanced". Remember you are not flying the FC, you are flying the airframe. "Tweeking" a multi rotor on a flat, level surface before callibrating the Acc is, IMO, by far the best way to ensure the airframe will hover flat and level in flight. It takes a bit of time to get the C of G right and level the air frame. I have done this with all of my quads (2 x KK2's and a MWC) and they all hover without drift in still air without any Acc trim adjustment. Early in my learning curve I spent many frustrating hours trying to sort out the Acc trim and eventually just gave up and went back to what i had learned in over 35 yrs of rc model building. Trust me, there is nothing more depressing than spending a lot of dollars and months scratch building a model then turning it back into sticks of balsa because you didn't pay attention to a simple c of g measurement. I know these boards are very capable of compensating for our mistakes but the code space taken up by things like acc trim and height dampening could be better utilised... My 2 cents worth.

Pete.
jonesy40001 is offline Find More Posts by jonesy40001
Reply With Quote
Old Jan 15, 2013, 12:04 AM
Registered User
jonesy40001's Avatar
Australia, QLD, Meadowbrook
Joined Sep 2012
180 Posts
Quote:
Originally Posted by rexless View Post
I've watched cheap toy quads descend worse than that and there was nothing broken!
Yeah, me too. Here is how a Hex handles a broken prop in flight, same FC, same pilot. at 9.15 in

RCV 32:ANOTHER prop failure mid flight!? (12 min 43 sec)
jonesy40001 is offline Find More Posts by jonesy40001
Reply With Quote
Old Jan 15, 2013, 12:53 AM
Dreamer
Australia, TAS, Ulverstone
Joined Aug 2004
2,055 Posts
Quote:
Originally Posted by jonesy40001 View Post
In this vid at 2min 50 the quad looses a prop and the descent is ...well kind of controlled. Ok so its a Naza FC but the KK2 is just as capable in AL mode when it is set up correctly. Enjoy.

http://www.youtube.com/watch?v=0OiYCuUay5s
Loosing a blade is sort of flyable ... loosing a propeller on a quad ...is not !!
There is a clip somewhere of Warthox doing a controlled flight back to himself after breaking a blade mid flight.
kaz1104 is offline Find More Posts by kaz1104
Reply With Quote