Copter crashes without error code

ArduCopter
1

Hey,

I have built an f450 drone with pixhawk, and I am having some issues with it. With a fully charged battery, it flies fine, without any issue. But when the battery goes around 40% or lower, the copter is having issues. If the copter is in the air, it starts to crash into the ground in a controlled way. It stays level, but it does not react to the throttle input, even if I change the flight mode. After it has crashed, I am able to arm again and take off, but after it reached 40-50 cm, the same happens.

I am using a ZOP Power 11.1V 6000mAh 45C 3S battery.

Here is the log (the copter crashed 3 times with this issue at the end of the flight):

What is causing this behavior?

2

i dont think its realy because of battery
you z vibration is too much and there is cliping in your log

Screenshot%20from%202019-09-15%2013-02-14
Screenshot from 2019-09-15 13-02-14.png1733×610 282 KB

For AccZ the acceptable range is -15 to -5.
for more info check this page of wiki

3

Thanks for the reply. I have fixed the vibration, the range is now withing accepted parameters. Clipping is gone as well. I flew again today, and when in Smart RTL mode, it crashed into the ground again (at 17:44). I am not sure what is the issue this time.

Here is the log:

Thanks!

4

Looks like its under powered/overweight to me. Graph the RCout’s, 2 motors are ~225 at hover. It should be closer to 180. Describe the craft and it’s all up weight.

Is your power module calibrated for current? Because the log shows it only supplying 2170mah when it has sagged to 10.1V.

5

The drone uses the following components:

  • F450 frame
  • Pixhawk FC
  • 4 x Holybro Tekko32 35A BLHeli_32 ESC
  • 4 x Racestar 2212 980 kv brushless motors
  • Flysky fs-i10 receiver
  • M8N GPS on mass
  • Runcam Racer 2 cam (for testing, will get a proper action cam with gimbal once it is stable)
  • Eachine TX801 with leaf antenna
  • ZOP Power 11.1V 6000mAh 45C 3S battery.

Total weight is a little less than 1,5 kg.

Current is not calibrated yet.

6

i see this now your flight time is 16 minuets !
i think your power module is not calibrated too.

7

What Props are you using?

8

My power module is calibrated for voltage.

Balanced 1045 carbon props

9

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a 6000mah 3s battery is near empty at 10.1 volt

10

Yes, but the crash has happened at 10.5+ volts

11

does your charger have ability to determine battery resistance ?

12

Yes, it can do that.

13

How much is your battery resistance ?

14

It’s under powered. Switch to 4S power. And you may as well be using Dshot protocol. You have the ESC’s for it.

Adding the action camera and gimbal to this craft as is will be much worse.

15

@dkemxr i agree with underpower but i don’t think a 4s battery is needed
I have same as this config with 30a current using this copter using only 10a at all
I think there is a problem with ESCs or a half dead battery

16

Internal resistance is 6.1 mR for cell 1, 6.5 mR for cell 2, and 5.0 mR for cell 3.
I have a 4s Turnigy battery, which will arrive next week. I will try the copter with that.
If the issue is with the ESCs, how can I test that?

17

Change to Dshot protocol and then ESC calibration is out of the equation.

18

I want to say that your battery resistance is fine

Try what @dkemxr said i think your problem will solve

19

Okay, thank you! I will try it, and post the results! :slight_smile:

20

Use Dshot 150. You may have to turn off Low RPM Power Protect" from BLHelisuite. Or it could be OK with 980kV motors. If you get no thrust then it will have to be disabled.