Hello DJI,

My Mavic Pro crashed in a fresh water Lake, but before the fly I performed an update. After a week I retrieved the Drone, cleaned, rinsed, sumerged very well with alcohol (never oppened) and proceeded to let it sit for a week in the furnance room. After the week, I decided to turn it on using a fully charged spare battery. The drone started as it would normally, but error massage “the battery authentication failed” came on. I tried downgrading /upgrading from my computer and no luck, the firware loaded to 32-35% and then failed with a battery error.

Also, the camera wasn’t focusing properly, but I managed to improve it by doing the IMU calibration, gimbal calibration and resetting camera settings, with that, the camera started behaving better and focusing properly.

At this point the battery error is preventing me from flying the drone. I have two batteries, one from the water crash doesn’t charge, only one LED is blinking during charge, but all LEDs blink when I press the power bottom (never put this battery to the aircraft),  the 2nd battery is healthy never had issues with it before, but that is the one having  the battery error.

Attached the screenshots of the error. Any help will be appreciated. Thank you.

Hi, we're sorry about the mishap that happens on your drone. Since this drone has experienced water damage, we would recommend sending the unit to our repair facility, however, submerging the aircraft with alcohol is not in accordance with our after sales policy or recommended option to fix the drone, I'm afraid that the warranty of your aircraft might be voided. For the sake of security,  we indeed don’t repair water damaged drone due to that the aircraft consists of a large quantity of sensitive electrical components. After it is water damaged, electrical components may be corroded, thus affecting its stability and security. Through the related tests, the repair of water damaged units needs to replace all the relevant components, and it is possible that the cost of repairing a water damaged drone is far higher than buying a new drone. Therefore, we advise that water damaged units are ineligible for a repair service. Thanks for your understanding and cooperation.

As simple as that. I'm amazed with your comprehensive solution Tony. Thank you very much DJI!

Soaking water damaged electronics in 95% alcohol is a accepted practice in the electronic repair industry, however I would be pretty sure your drone was under water for way too long, and corrosion has damaged the circuity in a way causing the battery error and is not recoverable.

Yeap, you’re right WRHershey, the use of isopropyl alcohol or distilled water are a valid practices to clean electronics. I’ve been in the electronics business for many years and those practices are presently used today. – a side note:  I believe, most of the Mavic Pro electronic assemblies are conformal coated – an extra layer of protection in favor and against corrosion  -

Even though, the drone is performing fine “besides the Battery Error”, the fact the drone was in water for a week and since the aircraft was “on” during the crash, unfortunately water in contact with electricity might have created a short or voltage imbalance that might have damaged the “Power Board” specifically, which I suspect is the board managing the battery discharge, balancing, temperature of the Lithium-ion cells (BMS Board).

If you see the pictures I posted, the individual cells are blank, the app still can read voltage and temperature, but not the individual cells voltages… to me this is an indication that the BMS or Power Board might be defective and not the battery. To isolate the failure, I’ll try a different battery and see the outcome…

On the good side, upgrade to the MP2.  Flying over water with the MP scares the crap out of me due the downward sensors.  Hope you get back to flying soon, just not with this one, but new one!

Hi Guys!

Just wanted to let you all know I finally  fixed my Mavic. I already have more than 2 weeks flying it and performs as intended, just fine!...

Thanks all for the replies. Happy flying!!

Hi Peter, just curious to know how managed to fix the battery issue, i am getting exactly the same issue with my OEM battery

I also would be interested in all the steps you went through to get the Mavic Pro up and flying again. Not that I want to crash in the water, but you never know when information like is might save your drone.

I had similar problem. It was fixed by slightly bending out battery contacts on the battery itself. Do nit touch terminals on Mavic side. Most probably, contacts on the battery went deformed or dirty.

Water damage is never good even after a fix. No telling when it will come crashing and hit someone. Your best bet is toss it in the trash and get a new drone.