Hello All. I have a quadcopter and am not sure if my batteries are no good or that maybe I am expecting too much. I have been sorting through my batteries, categorising them by run time to when an auto land occurs. I have the battery failsafe set low (I know) at 10.2V, with a 3s system. My aim is to get a reliable flight time so that I can start running more taxing missions.
The quad itself is an old aluminium X frame, with a fibreglass centre and fibreglass spring loaded legs. I have had it for years, originally with a kk 5.5 no-lcd board. The motors are I think 2830, probably about 1000kv, swinging gemfan 9*4.7 props. I have similar motors and same props on another kk2.1 quad and tri. ESC are skywalker 20A with original firmware.
So now I have it fully loaded up with a pixhawk, power module, 915Mhz telemetry, OSD, camera and 600mw tx (0.23 A just there). All up weight without batteries is 1050 grams. I know it is heavy... I have considered removing the landing legs and replacing with pool noodles or CF legs. I also have a discovery clone frame which would probably end up lighter but is not yet built up and this frame will have to lose it's motors and ESCs.
Flight time on my best 2.2 3s battery (25C - 35C) is 4 minutes and 40 seconds, with a resting voltage post flight of 11.3 V. Obviously even my best battery is sagging in flight a lot. Would I be better off to run two of my best packs in parallel? It is as though my batteries are not meeting their C rating.
I have a 5000mah 3s 20C pack in the mail. Hopefully I can get a better run time from this.
Also, I have gone through the telemetry and data logs and cannot find where the motor amps pulled is listed. Can someone point me to the right place please?
Thanks,
SixEasy
Replies
Do a search for Current. The Curr and CurrTot are what you are looking for in the logs.
http://copter.ardupilot.com/wiki/common-downloading-and-analyzing-d...
As for Flight time, air temperature, wind, style of flying will all affect the time you get out of the battery. Have you check the voltage of each cell? You might want to balance charge your battery. Going from a 2200 to a 5000 battery doesn't necessary give you longer flight time as it is heavier and the motors will have to work harder draining more current from the battery faster. Maybe you can go to a 4S setup?
Thanks Vinnie, I found the battery current in the mavlink logs. It is running at about 18A on average. I already balance charge my batteries and check them for balance after charging. I think you are correct in that I might have to look at 4s for my new frame. When the new battery shows up I will test it and post the results here.