Battery consumption

Gustavo:
It looks like there are several separate problems that might be independent or related:

1. The I2C errors are of concern.
2. The compass errors are also of concern.
3. Motors #4 and #6 (Counterclockwise) are working very hard.

The I2C errors need to be investigated to see when they are happening? At start up or during the flight. Upload the GPX file so that we can see when they are happening.

Did you calibrate the compass before this flight? You might want to check other flights to see if you're consistently getting this error. (In which case it might be the battery/heavy current wiring not being twisted or being positioned close to the compass.

Check the motor alignment. Are all the props level -- do the blade tips line up with the blade tips on the motors on either side? It looks like #4 and #6 are having to work so much harder than the other motors and there has to be a reason.

Andy.

 

Gustavo:
If you have a look at the GPX file using MK_GPXTOOL, you'll see that:

1. The compass readings are consistently a bit too high. This could be a sign of the fact that there is electrical interference from power lines, or magnetic interference from large masses of metal. By loading the GPX file into Google Earth I can see a broad strip of terrain to your north and east. It doesn't look like a road, but it might be power lines. See the image below:



2. Also, using MK_GPXTOOL, you can see that the I2C errors are at 39 from the start of the flight. They appear to be happening during the start-up initialization phase. I'm afraid that doesn't give any indication of the cause, you may have to remove the props and attempt to monitor the start-up/initialization using MK TOOL to see what is going on.

3. If Shaun Stanton has time, he might be able to do a correlation analysis (he has specific software for this) for motor #4 and #6 to see why they're drawing more current than the other motors.

Hope this helps.
Andy.

 

Sorry, Gustavo. I'm afraid I don't understand what you mean when you say: "Some suggestion?"
Andy.

 

I think it would be good if you did try and use MK Tool, Gustavo as, of course, I cannot predict when Shaun will re-appear on the forum.

Andy.

 

What you need to look for is whether the I2C errors occur during the first few seconds after you power up the copter.
The I2C errors are not apparently occurring during the flight.

The other thing, which is much harder to do without correlation software, is to try and understand what might be causing motors #4 and #6 to draw more current? If you look at the RC Sticks value in the Gridview of the GPX file, is there any correspondence between what you are doing with the RC Sticks and the increase in current for motors #4 and #6?

As I say, it might be hard to see this without suitable software that Shaun has.

Hope this helps.
Andy.

 

That suggests that the problem is on the Flight Control Board.

I do not know whether you are connecting the MK Tool cable to the Navigation Control board, but, if you are, you might want to disconnect the ribbon cables to the GPS and Navigation Control Board and connect MK Tool directly to the Flight Control Board and try again.

If you still get I2C errors, you have now eliminated that part of the I2C bus that goes to the Navigation and GPS boards, so that indicates that the errors are between the Flight Control, Power Distribution, and BL-Ctrl boards.

The next steps will be:
1. Disconnect the ribbon cable from the Flight Control Board.
2. Disconnect the Molex connector from the Flight Control Board (that connects to the Power Distribution Board).
3. Put the shorting pin on the MK USB adapter so that it shorts the two pins together (and thus provides +5 volts along the ribbon cable).
4. Connect the ribbon cable up to the Flight Control Board.
5. With MK Tool running, perform the calibrate and see if the I2C errors still occur.

(Don't forget to remove the MK USB adapter's shorting pin after this test!)

If they do still occur, then the problem is on the Flight Control board -- you may need to replace it or at least send it back to your dealer for testing.

If they do not still occur, then the problem is on the Power Distribution board or the BL-Controls. All you can really do then is to examine the board very, very carefully using a bright light and a magnifying glass. You are looking for any short "whiskers" of wire or solder that might be between the C and D terminals (and there are several of these) -- the C and D terminals are the I2C bus.

What you are looking to see is if there is any possibility of some kind of temporary shorting between C and D that might cause I2C errors.

Because the I2C errors occur when you calibrate, my hunch is that the problem is with the Flight Control Board.

Andy.

 

Gustavo:
If you open the GPX file with MK_GPXTOOL and look at the summary and the Gridview of the data, you can see the I2C errors.

Andy.

 

Thanks, Gustavo. Unfortunately, the machine I use for GPX file analysis is off-line while it is being backed up. It will be a couple of hours or so before I can have a look at this.

For anyone else who has a moment, I was going to check to see whether there were any I2C errors and whether the current draw was unusual.

Thanks
Andy.

 

Hi Gustavo.
Here's the MK_GPXTOOL information from the December 12, 2012 flight. It looks normal with the exception that:
1. The compass calibration is out of normal limits.
2. There are I2C errors.
4. Motor #4 is working a little harder than the other motors.

I think you might need to download MK_GPXTOOL and have a look at the GPX files yourself as I'm not quite sure what you're looking for.
You can download it from here: http://www.mikrokopter.de/ucwiki/en/MKGPXTool (scroll down below the three images and you will see the download link.)

Andy.