P3A Lost Connection (twice) At Hover / 15 Feet AGL, Couldn't Reconnect

[Fly Dawg]

Any thoughts on what might cause the short?

Not as of this point. Looking at FLY259, you lost connection at 4.5 seconds, basically immediately after takeoff. Whatever is going on is internal to the AC as far as I can tell. It is difficult to determine if the current spike that is there ( On FLY259 )was due to the takeoff and throttle up, which would be normal, or if the spike is also related to the loss of connection. I still suggest that you have an intermittent issue someplace since you did state that the AC has had a few mishaps. Maybe if @BudWalker has time, he could look this data over a bit more thoroughly and possibly give you a starting point to look.

 

[Just Mark]

Thank you, @Fly Dawg

After the latest crash, I did have a successful couple of flights (same location, just had to change batteries).

Is there a reason why it wouldn't reconnect with the RC after I switched off the RC and back on a couple of times? Does that just add more weight to the theory that something is wrong inside the AC? (I am guessing it would). But if it was just a spike, why no reconnect??? (Just wondering out loud.)

Hopefully @BudWalker will chime in.

 

[Fly Dawg]

After the latest crash, I did have a successful couple of flights (same location, just had to change batteries).

I was going to ask you if you used the same battery for these flights. Not likely that it is an issue with the battery but it is possible.

 

[Just Mark]

I was going to ask you if you used the same battery for these flights. Not likely that it is an issue with the battery but it is possible.

I only have two batteries, and on the prior successful flights (that happened AFTER the crash, but before calibrating the IMU), I did use both batteries.

So yes, the battery I used where the AC lost connection with the RC had been used at least once successfully after the crash.

 

[BudWalker]

@Just Mark , @Fly Dawg Sorry, I can't really add anything here. According to the .DAT there was an RC/AC disconnect. But, then you already knew that The P3 .DAT doesn't have signal strength data like the later DJI drones. I think you're looking at a trip to DJI repair.

 

[Just Mark]

@Just Mark , @Fly Dawg Sorry, I can't really add anything here. According to the .DAT there was an RC/AC disconnect. But, then you already knew that The P3 .DAT doesn't have signal strength data like the later DJI drones. I think you're looking at a trip to DJI repair.

Thanks. I was afraid of that.

Worried that the price of repair is not really worth it when I really want to save up for a P4P Pro

 

[Fly Dawg]

The P3 .DAT doesn't have signal strength data like the later DJI drones. I think you're looking at a trip to DJI repair.

Similar to what I was thinking. Thanks for the input.

 

[Just Mark]

UPDATE:

Based on @Fly Dawg wondering if the battery was an issue, I took my P3A out for a test flight with my OTHER battery and it seems to work fine. (A different battery than the one I used on Monday when the AC kept disconnecting.)

I just did two "flights" at one of our schools and gave it a pretty good workout despite not flying too far away. I was probably under 100' the whole time and only at about a horizontal distance of about 100', so it wasn't so much a range test.

But I did ascend quickly and then just let off the left stick (letting it snap back to the center). Did this a couple of times. Also, I used the left stick to spin around quickly, both clockwise and counter clockwise. I also pegged the right stick to the front, the back, the left and the right and then let it snap back to center.

In short, I tried to fly it like I was drunk.

Never lost connection. Flew perfectly fine, and no warnings whatsoever.

I did not bring my OTHER battery (the battery that was inserted when I was losing connection the other day) so I couldn't try it out.

So until I get a chance to try out that first battery again - and the nerve to actually test it out - I guess we could add "bad battery" to the list of possible suspects?

One other thing...

The day it was disconnecting, it was pretty windy out, and I was flying in P mode. Would that have anything to do with the voltage spikes? Maybe the AC was struggling to deal with a gust and then when the gust let up, it just had too much juice flowing to the motors that it didn't know what to do with???

 

[Fly Dawg]

Maybe the AC was struggling to deal with a gust and then when the gust let up, it just had too much juice flowing to the motors that it didn't know what to do with???

Not likely. Unless it was coincidental. The motor data looked normal. This is only based on the last flight log. It was a current spike and a voltage drop that occurred simultaneously at the point of disconnect which indicates a surge of some sort. That is why I suggested an intermittent "short". It could indeed be the battery, based on what you are describing with the second battery. Try the other battery again first, if it exhibits the same intermittent results then, ( And you may want to do both batteries ), VERY CAREFULLY, use some 90%IPO and clean the contact's on the battery and the AC side. It could be a "dirty" contact. Just a suggestion.

 

[Just Mark]

Not likely. Unless it was coincidental. The motor data looked normal. This is only based on the last flight log. It was a current spike and a voltage drop that occurred simultaneously at the point of disconnect which indicates a surge of some sort. That is why I suggested an intermittent "short". It could indeed be the battery, based on what you are describing with the second battery. Try the other battery again first, if it exhibits the same intermittent results then, ( And you may want to do both batteries ), VERY CAREFULLY, use some 90%IPO and clean the contact's on the battery and the AC side. It could be a "dirty" contact. Just a suggestion.

Thanks for the thoughts.

Could you elaborate on what you mean by VERY CAREFULLY a s you have bolded, capitalized and underlined it.

 

[Fly Dawg]

Could you elaborate on what you mean by VERY CAREFULLY

Referring to the battery contacts on the battery itself. By very carefully, I mean one pad or contact at a time, as to not short any 2 together with the IPO. You could use a very small piece of fine sandpaper and wipe it clean with a dry cotton swab, if you are not confident with the IPO. That is not as good, but it will allow you to determine if it were the battery contacts causing the issue.

 

[Just Mark]

Thanks for the clarification!

So the main issue (overall) when cleaning the battery contacts is to not short them out, correct???

 

[Fly Dawg]

So the main issue (overall) when cleaning the battery contacts is to not short them out, correct???

Look very closely at the contacts for any small signs of corrosion or "debris" that could cause intermittent connections. And yes, use the IPO very carefully.

 

[Just Mark]

Look very closely at the contacts for any small signs of corrosion or "debris" that could cause intermittent connections. And yes, use the IPO very carefully.

Thanks again. Will do.

 

[Just Mark]

Just an update:

Had another successful flight today with battery #2. About a 15-minute shooting somesome stills. No issues this flight. Still haven't re-tried battery #1 though.

 

[cneedelman]

Thanks. I was afraid of that.

Worried that the price of repair is not really worth it when I really want to save up for a P4P Pro

You could give Mike Holt a call, 530-277-5366, he'll answer questions over the phone and you can decide if you want him to take a look at it. He repaired my drone for a very reasonable rate. No association with Mike, just a very satisfied customer.

 

[Just Mark]

Thanks for the note. Oddly enough, i was just in Auburn this last Sunday (and Auburn is in the 530 Area code). Might be worth talking to. Thanks again.