I was testing flight time today with 2 batteries: 4S 5000mAh and 4S 3300mAh. With the heavier battery I didnt notice the problem but when I changed the battery to the lightter one I did notice that It was jumping, some times rolling peaks, sometimes throttle peaks, I'm not sure if it has something to do with PID because it happens very suddenly and randonly.Any idea?Another issue: Is it normal a 10 min flight time just hovering with a 4S 5000mAh batt?
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I would try to power the receiver and APM separately.
I did have problems with voltage drops. Was producing brutal servos excursions for me (i'm in the servo test period before going to fly with the ACM 2 beta).
The best practive i think is to power APM and Receiver with a BEC, and use opto isolated ESC to avoid problems.
Another solution at least for testing is to power the receiver and APM with a dedicated 1 Ah 4.8V battery.
If you want to do a servo test, you'll need to modify ACM code to put servos output in the 50 Hz loop, or you'll get dancing servos, even with good power voltage. RC Servos do not accept high speed > 50 Hz PWM signals.
For this modification, you need to edit Arducoptermega.pde :
- comment "set_servos_4();" inside "void fast_loop()" function
- add "set_servos_4();" at the beginning of "void fifty_hz_loop()"
- Compile and upload the new code with arduino IDE.
- Connect 4 or 6 servos with Y servo cables , firmly attach your multi to the ground, and test.
Watching for servos, you can see if there are instability problems on PWM outputs.
Next don't forget to back back the normal code for flying , because a 50 Hz loop is certainly not right to fly correctly.
Replies
I would try to power the receiver and APM separately.
I did have problems with voltage drops. Was producing brutal servos excursions for me (i'm in the servo test period before going to fly with the ACM 2 beta).
The best practive i think is to power APM and Receiver with a BEC, and use opto isolated ESC to avoid problems.
Another solution at least for testing is to power the receiver and APM with a dedicated 1 Ah 4.8V battery.
If you want to do a servo test, you'll need to modify ACM code to put servos output in the 50 Hz loop, or you'll get dancing servos, even with good power voltage. RC Servos do not accept high speed > 50 Hz PWM signals.
For this modification, you need to edit Arducoptermega.pde :
- comment "set_servos_4();" inside "void fast_loop()" function
- add "set_servos_4();" at the beginning of "void fifty_hz_loop()"
- Compile and upload the new code with arduino IDE.
- Connect 4 or 6 servos with Y servo cables , firmly attach your multi to the ground, and test.
Watching for servos, you can see if there are instability problems on PWM outputs.
Next don't forget to back back the normal code for flying , because a 50 Hz loop is certainly not right to fly correctly.