Unresponsive drone and when 2% battery makes a difference...

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I had a very strange flight Saturday afternoon. The flight started from my driveway. I took off then hovered so my kids could take a few pictures. The battery was at 98% after they finished. After that I flew out to 3473'. Turned around then headed back towards the house. I started to climb to see the sunset when it was just under 1100' away. I went up to max altitude but that shouldn't cause any problems. After that I'm not really sure what happened. It just started moving away on it's own. There were times when I was at 100% throttle to go forward but it was slowly moving backwards. I looked around at the scenery and checked the map to see where it was and kept trying to get it to do what I wanted but that wasn't working. I could control the altitude but it wouldn't fly in the direction that I was telling it to. It was just over 3900' away when the low battery warning came on (I have it set at 22%). The bird was trying to land at that point. I remembered that I could push through it to keep it in the air so I did that. I don't know what changed but I was able to regain control. I keep on the left stick to maintain altitude so it wouldn't land and pushed hard on the right stick to get it back as fast as I could. And that wasn't fast. It's horizontal speed was only 11-15 MPH. The battery was dropping FAST! I showed it to be 2189' away with 10% left and then 1280' away with 5% left. At that point I could see where I wanted to go (home) but knew it didn't have enough juice to make it. I kept trying while looking for a place to put it down. It was over trees at that point so it wouldn't have been good if to run out of power there. The only option was one street away. There was a cut de sac with enough room to put it down so that's what I aimed for. Full throttle forward and hard on the left stick to bring it down. Coming in hot!!! The bird was 160' up and 381' away from me with 1% battery. At that point I made it to my emergency landing area and got it down fast. Tree below it, back up a little, watch out for the utility pole, keep going down. Nailed the landing without hitting anything then jump in the car and take a quick driver over to get it. I later found that it was 50' up with 0% left. 2% might not seem like much but in this case it was the difference between my street and the next one over.

As for it venturing off on it's own. I still don't know what happened. I think it would take some serious wind to blow it backwards at full throttle. There was a little breeze but it wasn't that windy. Total flight time was 19:06. A lot less than normal so maybe the bird was fighting some serious wind.

I checked all of the controls Sunday morning. Everything was fine and there were no issues when I flew during the afternoon. That was an experience that I don't want to repeat!
 
Feels like I'm watching an episode of Air Crash Investigation! :)
Glad your bird made it just OK. Do share your finding about what went wrong, might be invaluable info for myself and others.
 
I had an event a little bit similar to yours, although not with your nail biting finish. Took my P4 out on a long distance trip, turned it around to bring it back and couldn't get past 15 kph and started to sweat. I raised and dropped the altitude trying to find a better speed and found a slight increase at one spot, nailed it in sport mode and came back at about 35 kmh. There was a slight breeze at ground level, so out of curiosity, switched it to atti mode at 120mtrs in height and it took off with no input at an indicated 30 kmh on the app. I checked the flight in the app and found that I was flying with a big tailwind on the way out and hence the struggle getting back. I'm still kicking myself for making such a stupid mistake. Never again.
 
Glad the story ended well!

Not really sure what this means though...


Sent from my iPhone using PhantomPilots

I looked over the flight record that night and as I was typing this post. The drone was 50' in the air when the battery level went to 0% so there was just a few seconds left. I think another 2% would have got it over the house between the two streets and into my yard. Or at least in front of me. 2% battery doesn't seem like much but sometimes it's everything.
 
I looked over the flight record that night and as I was typing this post. The drone was 50' in the air when the battery level went to 0% so there was just a few seconds left. I think another 2% would have got it over the house between the two streets and into my yard. Or at least in front of me. 2% battery doesn't seem like much but sometimes it's everything.
I don't want to go where you've just been lol. Did the flight record give you any idea of the speed you were travelling on the way out. Might give you an idea of what the wind was doing. I was going out at 60 kph and should have realised if I had bothered to take notice of the app at the time. I usually take it up to whatever altitude I intend to fly at, use atti mode, have a look at what the drone is doing and fly accordingly, simply forgot this particular time.
 
I don't want to go where you've just been lol. Did the flight record give you any idea of the speed you were travelling on the way out. Might give you an idea of what the wind was doing. I was going out at 60 kph and should have realised if I had bothered to take notice of the app at the time. I usually take it up to whatever altitude I intend to fly at, use atti mode, have a look at what the drone is doing and fly accordingly, simply forgot this particular time.

It was flying in the mid to upper 20 MPH range on the way out. Came back in the low to mid 20s and then dropped way down. Looking at it more now. It looks like the speed dropped way down as it climbed higher. There was a point when I wasn't doing anything so it should have been hovering but it was moving backwards at 14-17 MPH. Watching the playback, I was then giving it 100% throttle to come back but it was still going backwards at 8.6 MPH. No throttle after that and it continues to go backwards.
 
Difficult to say exactly, but whats worth mentioning, is that if theres little or no wind at ground, it can sometimes be up to 20-30 knts wind just 100ft up, and increasing.
Do you remember what direction the wind was? Also its not unusual for the wind to have different direction higher up than on the ground.
However, i experience weird random things with this machine now and then, last time this weekend, i was hovering just above me, but when moving the elevator/roll stick, it barely reacted until after 5-10 secs, and then it kicked in like normal, temp was on the + side.

If im uncertain about the wind, i always fly out towards the wind, then you will know how fast the slowest route will be, if its too slow, then just fall back downwind and land.
 
Okay, just took care of that. Link below. I wish it showed the stick positions and percentages to go along with the rest of the data. And/or be able to view it like I can in the app. That would show the bird facing me and having 100% throttle but it drifted backwards. I believe things started to go wrong between 9-10 minutes. That's when it started to drift to the right on the map. Yes, I was at max altitude (1640') but that shouldn't cause a problem.

One thing that I noticed was the battery was at 88% when I started. I guess I was thinking it was at 100%. I planned to come back after going up to view the sunset so I wouldn't have needed the whole battery. But an extra 2% would have got me back to the yard.

Phantom Log Viewer - PhantomHelp.com
 
Wow man. At that altitude it might have really been blowing. What was going on up that high massguy? Just curious. Def be interested to know what caused your problem here for sure.
 
You realize with these types of batteries it's really bad to run them down to 0%, right?

You really should only run them down to 20% if need be before you recharge. Every 30 charges or so DJI recommends running them down to 8% before charging.
 
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Wow man. At that altitude it might have really been blowing. What was going on up that high massguy? Just curious. Def be interested to know what caused your problem here for sure.

I don't know if it was very high winds or something else. I've only flown that high a handful of times and this is the only one that I had a problem. Looking back, I think I should have brought it down to 200-300' to see if that allowed me to regain control, Experience is a great teacher so I'll know for next time.


You realize with these types of batteries it's really bad to run them down to 0%, right?

You really should only run them down to 20% if need be before you recharge. Every 30 charges or so DJI recommends running them down to 8% before charging.

The battery went down to 0 because I didn't have control of the bird for awhile. I rather be safely on the ground at 15-20%.
 

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