I have the 3DR 2014 DIY Quad kit, and am trying to autotune it - but my battery does not have the power to complete the process :/
I am flying with 3S Turnigy Nano-Tech 4000mAh and 5000mAh batteries and get about 5 - 6 minutes of flight time out of it.
I would like to move to 4S batteries.
Will that result in a longer flight time?
And what C rating?
I am flying stock DIY kit with 20Amp ESC's and 880kV motors.
Replies
I couldn't even get my 2014 Quad to fly with 3S batteries. I have a GoPro 3s and a small gimbal on the front along with a small FPV camera, transmitter and video switch.
I switched to 4S 4000 Nanotech and 4S 2x2200 Lipoly and I only get about 3-5 minutes before I start to lose altitude. 10x 4.7 APC props. Hovers at 80% throttle. Motors are very hot. Cell voltage comes down at 3.8V which is way above being fully discharged.
Switched to 11 x 4.7 propellers and I still get a terrible 5-6 minute flight time before losing altitude at 100% throttle. Hovers at 73% throttle. Motors come down very hot. Cell voltage on landing is 3.65V. Based I'm LiPo discharge curves it appears I am only using ~60% of the energy in the battery before the voltage comes down too far to keep it flying.
So for my case of flying a small gimbal and GoPro it appears even 4S voltage, with larger props isn't enough to keep it in the air and get a full discharge.
There are some good data points for the 2014 quad in the comments of this Youtube video:
https://www.youtube.com/watch?v=fSQ5l206t3E
Why in the world would you chose these low kv motors only to have to increase the voltage to 4S or more to spin them fast enough to fly? Yes it is more efficient to spin large propellers slowly but that only counts if you can generate enough thrust to fly the vehicle. These things are getting hot too indicating they are undersized..
You might say: Robbie you are just overloading your airframe..
But this is a ~2kg quad with 300g of payload. There is probably someone on hobbyking who could fly 1kg of beer with a 2kg quad. I put the same gimbal, camera and FPV equipment on a ~290mm Blackout Mini Spider Hex with a 3S 3300 Nanotech pack and I get at least 10 minutes of flying.
Meanwhile, I am watching clueless coworker get 20+ minutes out of his phantom.
3DR: can you tells us what you were thinking here? So far this thing has been a waste of money. Fortunately the Pixhawk will go on to do bigger and better things in other models.
Yes your results are similar to mine. My reason for buying the quad was to learn how it all worked and have a machine I could progress with. I learnt to fly with it, I have played with aerial video and now I want to do mapping.
I have the tarot gimbal and Gopro 3+ with immersionRC 5.8gHz transmitter and MinimOSD and some BlinkM navigation lights. I also have a lidar lite sensor and a canon s100 setup for mapping I am yet to use and I just cannot get the same flight time as advertised on the 3dr website - and they use a smaller battery!
I have also tried the 11inch sloflyer props, so I have experimented but I am still wondering what is the best configuration and how can I get more flight time!
Maybe I need to convert it to an X8 to get more flight time but that will mean replacing the motors I have and buying more esc's and probably larger batteries...
Anyway, next arducoper release let's you split up autotune in pitch, roll, yaw, so less flight time is needed.