Battery Connection Burned out!

[Deleted member 99081]

I had a situation this afternoon when my P4A made an emergency landing after I got a "critical battery warning" - actually I brought it back from 1500m away at 30% battery and then got the warning at 8%. The drone landed safely, and I though all was well until I tried to re-charge it. The male charger connector would not fit flush, and when I looked at the female connectors on the battery they seem to be burned out (see photo below).

Can anyone advise on what has happened and why, and if this is a fault with the battery? Also, is the drone itself likely to be OK. A spare battery (and even this one) fits and shows a charge.

 

[Fly Dawg]

The drone landed safely, and I though all was well until I tried to re-charge it. The male charger connector would not fit flush, and when I looked at the female connectors on the battery they seem to be burned out (see photo below).

And yet another P4 battery issue. I have seen this particular issue 3 times prior with the P4's. They usually simply shut down and fall from the sky. You were very lucky. Unfortunately, there is no answer to your question as of yet. Unknown if it is the battery or the aircraft. I suppose you could attempt to retrieve the aircraft flight log and we could take a look there for a possible over current issue somewhere. Not likely to isolate the battery from the aircraft as the issue however.

 

[Deleted member 99081]

Thanks for the quick reply @Fly Dawg. Can you talk me through retrieving the flight data and I'll post it. I've also messaged DJI and will come back when I've had a reply to let everyone know what they say about it.

 

[2edgesword]

Does anyone know what those particular pins are for (power supply for motors, data transmission, etc.)?

If contacts become dirty or corroded their resistance will increase and that will increase the heat generated as current flows through them. During a long flight in warm weather the temperature may reach the point where it begins to melt the contracts or surrounding insulation material.

 

[Fly Dawg]

Can you talk me through retrieving the flight data and I'll post it.

I will post you a link following the photo below. If you notice there are two common damaged pins here, 3 and 4 it appears common to yours. This photo is from another P4 that fell from the sky ( Just for your Reference ).

See the link below the photo for the flight data information:

For the aircraft files, follow this link. The instructions are there. Retrieve P4 Dat
You will need to upload that data file to a sharable location such as dropbox, google drive etc..and share a link back here to that.

 

[Deleted member 99081]

Does anyone know what those particular pins are for (power supply for motors, data transmission, etc.)?

If contacts become dirty or corroded their resistance will increase and that will increase the heat generated as current flows through them. During a long flight in warm weather the temperature may reach the point where it begins to melt the contracts or surrounding insulation material.

I'm in Ireland. The current temperature is 41 degrees F. Pretty cold and the drone was flying for about 18 minutes.

 

[2edgesword]

I'm in Ireland. The current temperature is 41 degrees F. Pretty cold and the drone was flying for about 18 minutes.

Ambient temperature could play a factor but not necessarily. It all depends on how hot the contacts got based on a combination of heat generated by current flow and/or ambient temperature. Lower ambient temperature just means self-heating would have to be higher.

 

[Fly Dawg]

It all depends on how hot the contacts got based on a combination of heat generated by current flow and/or ambient temperature.

The battery temps and associated data will be in the aircraft .dat file.

 

[Deleted member 99081]

I will post you a link following the photo below. For the aircraft files, follow this link. The instructions are there. Retrieve P4 Dat
You will need to upload that data file to a sharable location such as dropbox, google drive etc..and share a link back here to that.

I'm having a stange problem with the DJI Assistant 2 app. When I try to run it (and I've tried downloading a new version) I get a red window with "This app has been blocked for your protection. An administrator has blocked you from running this app." WTF?

 

[Fly Dawg]

I'm having a stange problem with the DJI Assistant 2 app.

Can't really advise you on that, unless you do not have admin privileges on the computer you are using. Also, in the interim you could upload the device log. There might be something there usable. Not likely but possibly. Try uploading the device .txt log to this link and share a link here to that. Log Viewer

 

[Deleted member 99081]

Can't really advise you on that, unless you do not have admin privileges on the computer you are using. Also, in the interim you could upload the device log. There might be something there usable. Not likely but possibly. Try uploading the device .txt log to this link and share a link here to that. Log Viewer

Thanks again. I definitely have admin privileges, so I've no idea what's going on. I'm fairly sure this is the right flight log from the device (last but one flight today - last flight was with another battery):

P4A flight, Valentia, Kerry

 

[Fly Dawg]

@Valentiaman ....I realize this chart is rather busy, however, it appears that something occurred just as the aircraft turned around to head home. Looking at the graph you can see the huge current jump at that point. It is not unusual to see that much current draw, but notice as well the duration of the over 20 amps, and the increase in battery temp. It is very unusual to see that current draw for that long, especially so in a return to home situation. By the time you were almost to the home point the battery was scorching at over 55 degrees C. This data does not show what happened, it only shows the unusual nature of the high current for such a long duration. The only reason that I can think of is that the aircraft was really fighting a strong headwind on the way home. If there was no wind, then I can't explain why the data looks as it does. The aircraft data can possibly give more details on the what occurred, assuming you are able to retrieve it.

 

[WV. Rootman]

I'm having a stange problem with the DJI Assistant 2 app. When I try to run it (and I've tried downloading a new version) I get a red window with "This app has been blocked for your protection. An administrator has blocked you from running this app." WTF?

My computer thought it was a virus. It's ok to run it.

 

[2edgesword]

The battery temps and associated data will be in the aircraft .dat file.

Where is the sensor located that detects the battery temperature?

 

[Fly Dawg]

Where is the sensor located that detects the battery temperature?

Very good question. That I do not know the answer to. The temps are quite high regardless of location. Especially with the ambient air are 41F. I might expect that in the middle of the hot summer, but not at that temp. More concerning is the almost 2 minutes of over 20 amps. That is not normal.

 

[Deleted member 99081]

@Fly Dawg Thank you so muh for the information. I have saved the graphs and will send them on to DJI once they contact me (I've messaged them about the issue). You are quite right about the headwind - at least I can be sure it was windy, although I'm not ceratin of the direction. There was a point in the flight, though, that the P4A seemed to be almost motionless, as I was using right stick / right to roll it to the right. This might be when the spike in the battery heat occured?

 

[Deleted member 99081]

My computer thought it was a virus. It's ok to run it.

There's a lot of stuff online about the DJI Assistant 2 issue. Some say it's a Windows problem. There are workarounds, but I can't get it to run whatever I try.

 

[Fly Dawg]

There was a point in the flight, though, that the P4A seemed to be almost motionless, as I was using right stick / right to roll it to the right. This might be when the spike in the battery heat occured?

No, there were no stick inputs during RTH.

 

[2edgesword]

55°C is a hot running temperature for the battery but I question if it's hot enough to have scorched the terminals as they appear in the OP.

 

[Fly Dawg]

55°C is a hot running temperature for the battery but I question if it's hot enough to have scorched the terminals as they appear in the OP.

I agree, but the data is all we have to go by. Speculation, yes ( High Current over time = Heat) . Definitive, No.