I had my mini out for a spin yesterday. I was in a hurry, quickly took off, and in my haste I clipped some branches at the edge of a tree and the mini fell in the pool. I got it out in about 3 minutes and quickly removed the battery. I dried both as well as I could and let them sit for a day. Today I put the battery back in and pressed the power on button. The mini responded normally. This is good I thought. I fired up the controller and got a 'battery cell error' message. I was getting video from the camera and the gimbal appeared to work. The mini light was flashing as well.

So is the whole thing toast or do I just need a new battery?  The battery compartment in the mini has somewhat of an electrical short smell, but not too bad. I hate putting good money after bad, but I'd rather spend $50 than buy a new drone.

I would let it sit for at least a week before throwing the battery away, but you can always use an extra battery. Have you tried charging it?

Place it in a dry worm place , by a window or somewhere where the sun can penetrate the warmth inside to completely dry for a period of time. Above a heater so it gets all worm. Overnight seams to be a little short unless it was near heat.
Then I’d try charging.  
It has to get worm . Don’t melt it.

Thanks. The mini looks to react normally when I insert the battery. The controller is throwing up the error. Looking at the battery closely there appears to be some corrosion around the contacts, not much. I’ll let it sit another day and then connect the charger. The DJI flight software shows 2 good cells with plenty of power, so I’m a little confused about that.  If the mini continues to behave like it wants to fly I’ll spring for a battery if the error message doesn’t go away.

Thanks again.

Thanks donut. I noticed that the video was initially hazy like there was a fog. The longer I had it out the less haze it had. I now have it basking in 73 degree sunlight and will give it a try tomorrow.

Trust me on this one.  You will want more than one battery (I have four for my Mini).  Spring for another battery or two.

Peel the sticker off the battery cells to let the envelope breathe.
Soak the contacts area with isopropyl alcohol or even better contact spray. Let it dry.

Thanks guys. I didn’t think about taking the sticker off.  I’ll be using isopropyl alcohol on the contacts in a bit as well.

Good luck...It would be incredibly lucky if you don’t have water damage to the main board

Yep, thinking that. Stay tuned.

BTW, I bought one of those ARC lights from firehouse. It was flashing the whole time in the pool. I checked it out just now, no problems.

Hopefully, you'll be super lucky and have no issues.  Good luck on your first test flight.

Thanks Downtown. I’m a little more hopeful now. I was looking at batteries on Amazon and there was a review from someone that put their mini in a creek.  He did what I did for drying it and after replacing the battery it was good again. Since mine went into a pool and not a creek I hope that’s even less problematic.
Edit: I just cleaned the battery terminals, dried it thoroughly, waited a bit, then plugged in the charger. All 4 leds are blinking indicating the battery is damaged. My new one is coming tomorrow so I'll post an update then.

Yes, the battery it's the 1st one to go.... it takes just a splash. MM usually survives dips.

don't be so impatient i have been know to wait a week to let electronics "completely" dry out.  if it's not and you power it up....

I got my new battery yesterday afternoon, charged it up using my mini (I didn't have a separate charger).  After it was fully charged I powered up the drone and got the 'power system hardware error'.  I read some more, and I am supposed to initialize the battery somehow?  I saw something about the DJI Assistant 2 app but could only find DJI Assistant.  It looks a little outdated, but I downloaded it.  I fired the app up and it can't find any devices although bluetooth is enabled everywhere.  I'm thinking that's a red herring.

The Barometer initialization failure message is new, I didn't see it yesterday.


I can use the gimbal thumbwheel on my remote controller with the old and new battery, so somethings have power.  I get the video signal on my iPad as well.

After doing some searching I got the impression I might need to replace the ESC board.  I watched the youtube on that, but it looks to be a little beyond my skill set.  I've replaced board components within several laptops, replaced iPhone screens and batteries, and built workstations from the ground up, but I don't want to do that.  I''m guessing that a service order with DJI will be in the $100+ (any thoughts?).  That being the case, I'm ready to buy a Mini 2.  The flight distance on the mini 1 is really annoying anyway.

One last thing, I've looked at the Mavic Air 2 as well.  For me, the camera upgrade is no biggy.  Considering that's not an issue for me, any thoughts on whether that model is worth $350 more than the mini 2?

I had a repair service with DJI following a crash about 6 months ago.  I was very happy with the service, speed, and cost.  My total cost was about $95.00.  Like you, I contemplated upgrading rather than the repair - however the Mini 2 was not out, so I was looking at going to a Mavic Air 2.  You can read all about my crash and repair in this thread:  https://forum.dji.com/forum.php?mod=viewthread&tid=224044

As for the Mavic Air 2, it is a very capable drone.  I'm kinda holding out to see if DJI comes out with a Mavic 3 Pro that combines the best of the MA2 and M2P.  We'll see...

K6CCC Posted at 3-8 09:57
I had a repair service with DJI following a crash about 6 months ago.  I was very happy with the service, speed, and cost.  My total cost was about $95.00.  Like you, I contemplated upgrading rather than the repair - however the Mini 2 was not out, so I was looking at going to a Mavic Air 2.  You can read all about my crash and repair in this thread:  https://forum.dji.com/forum.php?mod=viewthread&tid=224044

As for the Mavic Air 2, it is a very capable drone.  I'm kinda holding out to see if DJI comes out with a Mavic 3 Pro that combines the best of the MA2 and M2P.  We'll see...

Thanks.  I read your first post on the thread you sent.  I too didn't use the RTH on the controller, or even the gimbal tilt (sheepishly I'll admit I didn't even know it was there), instead I used it on the iPad connected to the controller.  One thing I found out, if the device connected to the controller is too old (i.e., slow processor) or not enough memory, it will freeze.  I specifically bought the latest iPad mini to use with the Mavic mini.  However I'll be using the controller controls for those in the future.

Yeah, at $95 as a guess point for a repair, I'll be buying a mini 2 if there are no other solutions that present themselves.

Update: Upon further investigation I found that DJI Assistant 2 is a windows/mac program, not a smartphone thing.  I installed it on my laptop, but it only seems to be able to load the firmware for the drone.  In desperation I reloaded the latest firmware through that, hoping that would jiggle some bits, but I still get the error with the power system (or whatever).  The barometer error has gone away though.

I'd try to save the Mini... ESC boards are decently cheaper than a new drone.

m80116 Posted at 3-8 18:28
I'd try to save the Mini... ESC boards are decently cheaper than a new drone.

I saw that they weren’t that expensive, but as I said I’m fairly good at fixing electronics and this is beyond my skills. Plus if I did it and it failed mid-flight, I don’t want to have all that responsibility. It’s also possible that more circuitry is bad so the total repair cost is uncertain IMHO.  After things open up more I’ll see if there’s a local repair shop that can give me an estimate.

Sine the MM1 battery can be used in the MM2, I’ll just keep those and use them. My new MM2 arrives Thursday.