WK-M Crash

[jhardway]

Not a bad one it happen about 8 feet from the ground but it was kinda weird so I have some questions. The first one has to do with battery voltage and when on a 11.1v what would be a good voltage to land the system. I ask this mainly because of the way the crash happened, it seemed that the system slowly lost power then fell out of the sky, like it could not keep up with what it needed to stay afloat. When measured the battery's voltage it was at a 10.6v, I looked a another battery that I had used just before and that was at 10.2 I had not problems, now I am trying to figure it out.

So is there a danger zone, in theses ranges, Other then the obvious of properly setting the voltage meter in the firmware. I looking for a general guide line. Also is this something a 14.7V would more over come


My set up is an Xaircraft x650 with Xaircraft motors, and dji 12A ESC's

Thanks

 

[Gunter]

I noticed the same thing when the battery gets low, it loses altitude and I have to give more throttle to keep it up.

I have a voltage meter which gives a loud chirp when the battery gets to a certain level...better to have an audio alert instead of a flashing light, you immediately realise that it's low.

 

[DennyR]

I have found that the ESC is a reliable way to let you know that you are about to go down. Hi Model has three settings. I see a little instability for a few seconds and then is will start to descend. So I set my timer 1 min short of that time. I have calibrated all of the batteries as they are not the same. What I liked about my DIYDrones set-up was that you could set it to have the computer speak the volts in real time. Based on the AUW of your model you will soon learn how much duration it has.

 

[redridinghood]

I think the DJI WKm calculates the throttle needed to hover on first liftoff. When the volts go lower than a set threshold the craft needs more throttle to keep altitude.

 

[jhardway]

Thanks for the responses, I am wondering what other are setting the voltage meter warnings at. I am planning to start exploring the thresholds to figure out flight time and warnings. A tuning process, I will be calling it.

 

[andymotor]

So did you set the sencond level protection 11.1v? When the second level protection triggered, LED warning will be on, you should land ASAP to prevent your multi-rotor from crash.

 

[RTRyder]

So did you set the sencond level protection 11.1v? When the second level protection triggered, LED warning will be on, you should land ASAP to prevent your multi-rotor from crash.

I know on my quad once the LED starts blinking RED if I don't land soon it will land itself, I would not attempt to make it keep flying at that point unless maybe it was over water or some other undesirable landing spot. Then again once the LED is blinking first level voltage warning you should be flying back to land anyway, if you have the settings calibrated correctly you will get a minute or two of flight time before it goes red into second level and at that point you're just about out of battery power.

Ken

 

[Gunter]

I know on my quad once the LED starts blinking RED if I don't land soon it will land itself, I would not attempt to make it keep flying at that point unless maybe it was over water or some other undesirable landing spot. Then again once the LED is blinking first level voltage warning you should be flying back to land anyway, if you have the settings calibrated correctly you will get a minute or two of flight time before it goes red into second level and at that point you're just about out of battery power.

Ken

Ken, as a matter of interest, what battery are you using (how many cells) and what settings are you using on the 2 different warnings?

Thanks,

Gunter.

 

[RTRyder]

Ken, as a matter of interest, what battery are you using (how many cells) and what settings are you using on the 2 different warnings?

Thanks,

Gunter.

On the quad I use a pair of 2s 5000 in series. I think I have first level set to trigger around 14.4 volts and second level at 13.8, if I stop flying right around the time first level kicks in I'm a bit above 20% capacity left in the packs, if I let it go until it autolands there's about 5 to 8% left which is definitely pushing into 'about to fall out of the sky' territory for battery reserve. In any case it's a nice backup feature but I still fly by the timer I have set on the TX. When it goes off I know have a minute or so to get back into close proximity and shortly afterward it may start into level 1 warning depending on the type of flying I've been doing, time to land and be nice to the batteries.

Ken

 

[jhardway]

Ok going back into what I did, on my 11.1 battery (thunder power 5000 c45 - heavy) but i am getting about 11 min out of if, i have set my first threshold to 10.85 and my second to 10.6 at, 1900g Its doing fine, however when I was at 2250g its probably best to click those numbers up 2 - 3 tenths, as I am seeing. Looking into it thought at the 2250g I am not completely happy with the stability of my current motors, I am thinking of moving to the AVroto 2814 for more lift compacity.

 

[Sebas600]

found this on wmk site

PW Port
This port provides power to whole WKM system (MC, IMU, GPS, LED) which does not need to get power from any 3-pin servo port. The output voltage is 12.6V If input voltage from battery is higher than 13V; the output voltage will follow the change of input voltage (0.4V lower than it) If input voltage from battery is lower than 13V. Its maximum output current is 2A.