A2 voltage readings with Tiger u7 (v2.0) motors

BATCAMuk

New Member
Hello everyone, Help needed!
We have been using DJI's WOOKONG-M flight controller for several years now. Recently we purchased 2 new systems, both with the A2 and both using T-motor u7 (v2). One system is a flat 6 and the other a flat 8. We have always used the DJI iOSD overlay for telemetry, specifically voltage readings. It seems that DJI have changed the way they read voltages on the a2. We now have figures randomly moving anything from 22.5 to 20.5 in split seconds. The figure constantly changes making it near impossible to get an accurate reading of where the Lipos are at. The Wookong-m seemed to give a good average of the Lipos and its as though the a2 now reads the current at any given time. Annoying as well these figures trigger voltage protection. So you literately be in flight for a minute on fresh batts and get yellow or red lights on a move which will continue for the whole flight until you power down. Anyone had this issue and know of a workaround? Help much appreciated.

Jon
 

Bartman

Welcome to MultiRotorForums.com!!
have you tried to do the voltage calibration process within the A2 Assistant? you might also want to disable the Voltage Protection until you know for sure what you're getting from your batteries on each of those helicopters
 

Hexacrafter

Manufacturer
BAT,
I have always seen DJI iOSD data and other voltage telemetry system data behave the way you describe.
The No Load vs Load voltage on heavy lift aircraft do fluctuate massively... especially with larger motors and the need for sudden "burst" spikes in power draw as the aircraft corrects to stay level.... remember these are massive motors/ Props & ESC!!!
This is even worse when in high wind conditions or with a very tightly tuned aircraft that is fighting to maintain a very tight position hold.
As far as voltage protection... you will need to determine a "safe" No Load voltage to use by testing the displayed load voltage and no load voltage.....but this is a subject for another thread.
 

BATCAMuk

New Member
We had tried setting the voltage in the assistant still no help i'm afraid. Interesting that you have always seen the data like that in the past. The new elements of our systems are flight controller, esc's and the motors. So that would explain if it is just a case of huge power draw. It's a real shame as we could always get the most out of Lipos in the past, running them to 21.7v from the iosd display. We now have consistent spikes down to 20.3v after a couple of minutes, get a load of warnings (including separate buzzers on the lipos!) land it, only to find we have 50-60% capacity still. Really annoying.
 

Hexacrafter

Manufacturer
Another thought....
Are your batteries healthy???
With the heavy lift applications you will need a good quality battery pair...
I see no information about the batteries used, but for a Flat 6 or Flat 8 I suspect you are using at least (2) 10,000 mah or (2) 16,000 mah batteries from a better battery manufacturer like Gens Ace, Tattu, Pulse....
Cheap batteries or dying batteries can also perform poorly with the bigger aircraft....
 

BATCAMuk

New Member
We have always used Overlander batteries and never had an issue. We are currently using 2x 9000mah 6s overlanders. But also experience the issue with 2x 12000mah 6s overlanders as well
 

You may want to check out putting power conditioning capacitors ahead of your ESC's. I have 3 - 470uF 35VDC Electrolytic capacitors in parallel with the circuit on all six of my ESC's. (8460uF total!) I'm flying a TarotT960 with an A2 setup and I get super stable voltage readings during my flights. In fact when I unplug the main battery the electrical system continues to function for a good 2 seconds.
I have my ESC's mounted out at the ends of the arms and had been concerned about the effects of extending the ESC out past the 6" rule.
I am happy with this setup and the ESC's and motors are very responsive. There are several threads out on the forums discussing putting capacitors in the power train. It works well for me IMHO.

Bob
 


Top