My first and second crash... Now motors wont turn on... Might need some help on my Phantom 4

Dr_VonDuck · Mar 2, 2019

So i took my P4 out for a night flight near the Huntington Beach Pier. first battery was a fun flight, a little bit f FPV jitter and delay on my screen but no biggie. put the second battery in and flew most of it fine then decided to take a nice slow easy pass under the pier (over the sand). The wind was only about 2 or 3 MPH and no gusts... when suddenly my drone decided to just drift into a pylon against my control... so it landed in the sand after about a 4 or 5 foot drop, bent the left landing gear. i picked it up, got the sand out of the gimbal, whole thing worked fine aside from the bent landing gear. so i i fly it a bit more and get to a low battery state and bring itto a safe landing spot, however the countdown for automatic RTH kicks in and takes over control to bring it back to the home position and promptly swings the drone into a big metal pole nearby and drops my drone again about 2 feet onto hard concrete and ejects the battery.

So, no further exterior damage except maybe the props which i am about to replace anyway, so i plug the battery back in to test it before packing up and it takes a while to warm up, longer than usual... and when it says ready to fly it wont start the motors... so i swap to the battery from earlier but it seems to behave the same way.. both are very low power at this point but i couldnt even get the motors to spin if i wanted to discharge them. Also the usual beep with the subsequent echoing beeps as it checks the motors seemed delayed...

So i guess my question is: Is there some limiting factor that keeps the props from starting if the battery is in autoland levels?

and: has anyone else encountered this?

Again neither fall was enough to damage the body, just the one bent landing gear and a battery ejection.

Any input is awesome. hoping i didnt bust the flight controller or something.

Ansia · Mar 2, 2019

As for the first question. Yes, once the battery reaches are certain voltage level, the motors wont start. Once the forced auto-land is triggered and it lands, you will need to charge the battery in order to fly again.

Please verify that the battery that got ejected did not pop a cell and is swollen. That is a real danger that could make your drone drop from the sky due to false readings.

Your drone crashed into the pier, because of low light. Sensors don't work well at low light. Also, when you flew under the pier, the drone went into ATTI and could not hold in place.

Dr_VonDuck · Mar 2, 2019

Not even a scratch on visual inspection of the batteries. Battery cells are all in decent shape and reacting to charging well. Going to test it later to see if it boots up fully and gets the rotors turning.

Ansia · Mar 2, 2019

Dr_VonDuck said:
Not even a scratch on visual inspection of the batteries. Battery cells are all in decent shape and reacting to charging well. Going to test it later to see if it boots up fully and gets the rotors turning.

Keep an eye on the voltage of each cell.

Dr_VonDuck · Mar 2, 2019

so just plugging in a battery and booting it up, had a normal boot up time and beeps, rear lights during warm up flash red-green-yellow, then after warm up have a long red light and several yellow flashes. i know there are error codes displayed by the lights but i cant find what each one means for the P4. any help on this? it may be noted that i live in the big nono zone right next to an airport so it may be that im just grounded.

Ansia · Mar 2, 2019

Dr_VonDuck · Mar 3, 2019

Ansia said:
View attachment 109113

This is awesome! thanks for the link.

So one thing i noticed during my trial power up is that there is no battery level reading... so im thinking there may be a problem with the module that meters the battery. this happens with both the batteries so im thinking its one of the internal parts.

Dr_VonDuck · Mar 3, 2019

Dr_VonDuck said:
This is awesome! thanks for the link.

So one thing i noticed during my trial power up is that there is no battery level reading... so im thinking there may be a problem with the module that meters the battery. this happens with both the batteries so im thinking its one of the internal parts.

I should also mention that the remote connects to the drone well and when i push the stick left and right i get the usual response from the gimbal. it pretty much does everything except read the battery level and start the rotors. and of course theres the rapidly flashing yellow lights.

Ansia · Mar 3, 2019

Dr_VonDuck said:
I should also mention that the remote connects to the drone well and when i push the stick left and right i get the usual response from the gimbal. it pretty much does everything except read the battery level and start the rotors. and of course theres the rapidly flashing yellow lights.

I am no expert, but perhaps one of the pins inside the compartment is twisted and not making full contact, therefore not giving enough voltage? If not, then the main board may be damaged.

Dr_VonDuck · Mar 4, 2019

Ansia said:
I am no expert, but perhaps one of the pins inside the compartment is twisted and not making full contact, therefore not giving enough voltage? If not, then the main board may be damaged.

Well on first inspection of the pins they all SEEM to be in line, but its difficult to know if they are functioning properly until i dig in. at this point its time to crack open the body and look at the internal components to ensure everything is hooked up properly and nothing is burnt from the battery ejection.

Fortunately i know a guy that works on circuit boards so if theres anything damaged like that he may be able to fix it. I just find it odd im getting the flashing lights for no radio control signal when my Radio is connecting fine... maybe a firmware flash is in order?

Ansia · Mar 4, 2019

You can try it, but I highly doubt it will fix your issues. Best answer is to take it to your friend. He will determine if the board became broken.

Nightwolf · Mar 4, 2019

Dr_VonDuck said:
maybe a firmware flash is in order?

I wouldn't flash a bird that won't fly until i had exhausted every other option. You may just induce more errors

Chrislaf · Mar 4, 2019

Also, before cracking the shell open, you may want to upload you flight log to Phantom Help log viewer located here
DJI Flight Log Viewer | Phantom Help
to see if any of the experts on here can give you more info about your problem.

Chris

Nightwolf · Mar 4, 2019

Chrislaf said:
Also, before cracking the shell open, you may want to upload you flight log to Phantom Help log viewer located here
DJI Flight Log Viewer | Phantom Help
to see if any of the experts on here can give you more info about your problem.

Chris

^^ That^^

Dr_VonDuck · Mar 10, 2019

So heres the log from the first crash, went under the pier and lost GPS so it went into ATTI mode and drifted into a pylon...
DJI Flight Log Viewer - PhantomHelp.com

Heres the log from after i tested it after the pylon/drone love scene
DJI Flight Log Viewer - PhantomHelp.com

And heres the last one where it shows that at the end it decides to return home right when im trying to land it and flies directly into a flag pole.
DJI Flight Log Viewer - PhantomHelp.com

Dr_VonDuck · Mar 10, 2019

Update on the Drone's state:

It was having an IMU error, it wasnt showing its state in my warning and error messages so i opened it up, checked the connections, and gave it a mild flick of the old fingers and then powered it up. now its reading as normal, but im still not getting a bsttery level reading and still getting a rapid yellow flash.

Dr_VonDuck · Mar 10, 2019

Found the culprit.

Dr_VonDuck · Mar 13, 2019

Good news today! After nearly a full disassembly the ribbon cable has been replaced and the drone is now working and fully functional! The part comes in a set for 15 bucks from my local DJI retailer and ive seen it on amazon for 25. Fortunately it wasnt the IMU or Flight Control boards. I will be flying this weekend with my pops who just bought himself a mavic pro plat. WOOHOO!