MA survived bathing a river... and started to have battery error

[Nickes]

\\ Repost from DJI forum //

Hi guys !

The worst case scenario happened to me a few weeks a go : take off under the trees (no gps), fly over a bridge, kids running away, bad move, branches, drop, bath ...
I retreived the MA in less then a minute, all shut down. It was all my fault here (will try to post the last 2 scds video into water before it died).

Notes for next time :
1. Never fly in a rush,
2. Never fly in a rush,
3. Never fly in a rush.

I also (surely a bad idea) tried immediatly to power it on. Made strange sounds, lights and move so I switched it back off.
Then removed the battery, blew air (with mouth) in every hole removing as much water as I could, spent 1/2 hour in the car blowing dry hot air from ventilation while waiting for kids to return.
Back home (30 minutes drive), tried the rice bag trick (MA + battery) overnight and, next morning, blew some WD 40 « for electronics » everywhere.

Grabbed a fresh battery, powered it on and ... it was responding 100% normal !!! Until ... it showed the feared « battery error », i.e. « check if well secured, restart, if not responding contact support » ... After a couple of tries I found a way to get it in the air despite the battery error showing up as I really wanted to see if it would be able to fly again : and it did !!!

I have had a couple of flights since then and the MA behaves absolutely normally appart from the battery error !!!

Battery error symptoms :
- Normally, prevents to take off,
- Battery info appears in the battery settings in the DJI go 4 app but not on the main screen while flying,
- Does not show possible remaining duration of flight while in flight (duration display remains as : .. : ..)
- SOMETIMES comes back to normal (no battery error when MA is turned on or show remaining capacity in flight on the app) for a few seconds / minutes before desappearing again.

I tried several times to refresh the firmware, did it with my 3 batteries but problem remains.
To be noticed : the battery that went down with the MA works normaly.

I suspect a hardware issue on the power board of the MA, maybe a shortcut when it dropped or right after when I tried to turn it back on.

Just wanted to let you know. I will try to install a new power board.

Questions:
- Did someone here tried to change the power board at home ? How did it go ?
- Does anyone knows how to perform (if possible) a full system diagnosis in order to identify the faulty component ?

I’ll keep you posted with further developments.

 

[Nickes]

Update :

Hi there !

Just to let you know, as I was getting a hand on the very last components needed to switch my ESC board, I noticed the battery error started to occur at a decreasing frequency.
I then updated the whole thing to FW v01.00.0500 in late September.

Since then, the battery Error did not reappear ... My all 3 batteries behave absolutely fine (all stats are good and nomral) and the craft is performing the same way ...

I can not tell so far which of the update to the last FM, me flying in a tropical environement or the decreasing of mean daytime temperatures (I noticed that battery errors used to trigger when the whole craft was gaining in temperature) is involved, but the conclusion is that it still flies and behaves normally.

I've doubled the number of flights since the accident happened (60 then and 126 now).

I just guess I have been lucky.

 

[raven swe]

wd40 leaves an oily residue, alcohol base solution may have been better,

 

[Nickes]

apparently the « special » WD40 for electronics (contact cleaner) does not !

 

[大疆御Air]

Hope this video help

 

[Nickes]

yeah thanks! already spoted this one that I added to the « mavic air teardown post » here

 

[raven swe]

ahh missed the « for electronics » bit,,

 

[Nickes]

Update 2 :

Finally ended up dismantling the Air to change the ESC card after ... I bathed for the 2nd time ... but in the Caribbean Sea this time : only for 3 seconds, immediately removed the battery and poured fresh water on it before leaving to dry for a week - no rice this time as it leaves small pieces -, started normally after that except for ESC 3 and 4 errors ....

It took me about 4 hours (using the very useful thread : Mavic Air Teardown ) to :
- Change the ESC board
- Install new 3 and 4 motors

Fly as a good as before !