DJI Wookong M - Voltage Monitor - Flight Time Heavy Lifter

[roryhinds]

Anyone out there with more knowledge of the Wookong M's Voltage Monitor and Heavy Lifting SkyJib 8?

I have a SkyJib 8 with
AXI 2826/12 motors
65Amp ESC's
15x4 Carbon Fibre Props
2 x 12000mah 5S 100C constant batteries

I'm seeing only 4 minutes flight time with my full load (total weight 12kgs with AV200 + Red Epic) and I think I have my Voltage protector settings not quite right.

When I landed after 4 minutes I still have 47% left on the batteries so wonder why the Wookong made me land and I wonder if I can adjust the settings to get another 2 minutes flying time and still be safe.

My cut off was set to 18V.
Is it safe to set this to a lower figure and use more % of the batteries.
I'd like to get it that I'm landing and on the ground and have 20% left in the batteries. (Yes I'll come home before that time for sure)

The AXI 2826/12 motors are rated to used 3S - 5S so thats 11.1v to 18.5V
Would I be safe to run my 5S batteries to 17V which would be 3.4v per cell?

What are others doing with Heavy Lifting and flying a UAV of 12kg's (26.5lb)

 

[Aerial Media Pros]

Rory,

I think your issue comes from the load put on the batteries under power. Sitting on the ground, Voltage probably reads well above 18v. But once you get it up in flight carrying 12kg, the Amp draw, drops the voltage down, triggering your wookongs Voltage monitor. I personally do not use the voltage monitor on heavy lifters, or on any of the S800's. I simply figure out my flight times, and go off that. The problem with the voltage monitor, is that if it goes into its second level of protection, it cuts power to motors way down. On most heavy rigs, this causes the copter to fall to fast (Controlled fast decent) resulting in damage. For this reason, I turn the voltage protecton off. But to answer your question, you can lower the number on the Voltage Cutoff, and that will give you more flight time, till where your using up more of the packs capacity. Hope that helps,

Patrick

 

[roryhinds]

Thanks Patrick, I really appreciate your input.

I dropped the Voltage Monitor on the Wookong to 17.5V (3.5v per cell) and have been told by MaxAmps that I can't go below 15v (3.0v per cell).
I just test fly and got 14 min 27 sec with no load (8kg skyjib & 2 x 12000 5S batteries). It was down to 9% of the battery @ 17.5v

I am happy with that as I should get my desired 6min flight time with a full load (12Kg Epic camera).

I had the iOSD connected which I could monitor the Voltage and it got down to 17.5v so I could push it more if needed. I would like to get to the stage of turning off the DJI Voltage Monitor and know how much time I can get from the system and work from there and just monitor the Voltage.

Does anyone know of a good voltage meter to monitor the voltage while flying? Using the iOSD seems a bit over kill for that job.
I saw this https://vimeo.com/42225781
Does any know what the voltage meter is?

 

[mbsteed]

I use specktrum equipment, so we use the spektrum telemetery system and that seems to work well (I have it displayed on an 10t RX and on a iTouch with audio alerts). We have it setup to monitor altitude, RX voltage, flight voltage, and ESC temperature. Thus far it seems to work well.

http://www.spektrumrc.com/Air/Telemetry.aspx

 

[tombrown1]

Thanks Patrick, I really appreciate your input.

I dropped the Voltage Monitor on the Wookong to 17.5V (3.5v per cell) and have been told by MaxAmps that I can't go below 15v (3.0v per cell).
I just test fly and got 14 min 27 sec with no load (8kg skyjib & 2 x 12000 5S batteries). It was down to 9% of the battery @ 17.5v

I am happy with that as I should get my desired 6min flight time with a full load (12Kg Epic camera).

I had the iOSD connected which I could monitor the Voltage and it got down to 17.5v so I could push it more if needed. I would like to get to the stage of turning off the DJI Voltage Monitor and know how much time I can get from the system and work from there and just monitor the Voltage.

Does anyone know of a good voltage meter to monitor the voltage while flying? Using the iOSD seems a bit over kill for that job.
I saw this https://vimeo.com/42225781
Does any know what the voltage meter is?

You're getting 14 minutes with NO load and 24,000 mAh? I think the S800 gets more flight time with no load and 10,000 mAh. Something seems awry here - maybe it's just me.

Tom

 

[roryhinds]

Hi Tom, not sure what the weight of the S800 is but my SkyJib weighs in at 8kg's without a load (camera & gimbal).

 

[tombrown1]

Wow! Didn't realize it was 8kg. So I guess that might make sense then. Sorry to hijack.


Tom

 

[gtranquilla]

I read somewhere in this forum that one can adjust the MR vertical gain so that the MR will drop more slowly on 2nd level battery protection....... Wish I could find that posting.... with considering if it could save a very expensive payload.

Rory,

I think your issue comes from the load put on the batteries under power. Sitting on the ground, Voltage probably reads well above 18v. But once you get it up in flight carrying 12kg, the Amp draw, drops the voltage down, triggering your wookongs Voltage monitor. I personally do not use the voltage monitor on heavy lifters, or on any of the S800's. I simply figure out my flight times, and go off that. The problem with the voltage monitor, is that if it goes into its second level of protection, it cuts power to motors way down. On most heavy rigs, this causes the copter to fall to fast (Controlled fast decent) resulting in damage. For this reason, I turn the voltage protecton off. But to answer your question, you can lower the number on the Voltage Cutoff, and that will give you more flight time, till where your using up more of the packs capacity. Hope that helps,

Patrick