Drying water damage in rice.

Yet another post on yet another well pushed wives tale!

My quadcopter landed in water , what should I do???

To which people say put it in rice to dry it out!

WRONG!!!!!!

Ask any qualified electronics engineer and they will say do not do this, you will end up with rice residue getting into electronics and causing even more damage!!!!!

If electronics whether drone or anything else gets dropped in water, remove battery asap and then at least use a hair dryer (not too hot or you will melt plastic) and leave somewhere warm to fully dry out.

Or better still open up say quadcopter and dry boards out with hair dryer and then leave in a warm place to totally dry off.

Or is something is dropped in sea water, then remove battery asap and rinse in a bowl of distilled water and then dry it out.

So please stop with the bury it in rice , in fact it may seem to work and then once that rice residue eats it way through the board it will end in tears one day.

I seen this too many times when I am repairing stuff that has been dumped into rice and it causes a right old mess and a lot of times make a repair uneconomical.

 

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Bedding in lipo’s

Something I keep meaning to write is a post about is the old wives tales so many keep making on forums and youtube videos, and that is you need to make 10/20 flights before you get the best flight time from a new battery.

Drives me nuts this one!

Lipo batteries DO NOT need any bedding in for 10/20 flights!!!!

Even the manufacturer’s of these batteries state you do not need to do this and there battery will not perform any better , and yet people still advise people to run there new batteries in!

If the manufacturer’s state its not needed, then why do users think they know better????

There are even some youtube videos that have tested this and they also come to same conclusion , bedding in lipo packs does nothing to increase flight time or battery life.

Looking after your packs and not running them to low or charging at a excessive charge rate and keeping at storage voltage when not used for a while is best common sense approach.

There is a small chance that as the bearings wear in , it could and I state only could increase flight time a very very tiny bit, but for sure the battery chemistry does not work like this and those that manufacture the packs certainly never state they need bedding in.

I dare say people out there will still push this old wives tale, but that is all it is … A tale…

Happy flying 🙂

 

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DJI Mavic Pro Platinum repair

Update on the salt water damaged DJI Mavic pro platinum.

Sadly although the esc was making the startup dji tones, it turns out it was damaged and its not supplying the supply voltages to the main board.

On closer inspection the print tracks going to connectors are all badly corroded and if available , would at least need all new connectors.

So for now this project has hit a brick wall as thus far parts it would need to get it working again will at least be:-

Esc board , main board , 2 x motors.

Issue is getting hold of a platinum esc board is very difficult in the uk.

Can order from China , but many suppliers claim there esc is for platinum version , but show the older board. The platinum version has the newer esc chips on and so hence would rather get the correct board.

Anyway with how much the prices of second user Mavic pro’s have dropped, that means the cost of a esc board and main board etc really makes this uneconomical at present.

Its a shame, but when a craft has landed in the sea and left to dry out with battery left in = a uneconomical mess.

There is a chance the main board still works, but for sure at all the quadcopters I have looked at that have landed in the sea and not rinsed with clean or distilled water asap and battery removed, the esc part always dies.

Links to other posts on this project:-

1 DJI Mavic Pro Salt water damage

2 DJI Mavic pro ESC test

3 DJI Mavic pro Camera teardown

 

 

 

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Mavic pro camera disassembly

Just a quick teardown of the Mavic Pro camera to see if any salt water corrosion made it into the camera and connector and surprisingly there was none.

So maybe camera part still fine, but no doubt the gimbal motors which were almost seized when I got it and even though I cleaned them up and they move freely now will prob show gimbal over load error as they are very sensitive to any friction and bearings prob shot.

But we shall see and the gimbal part with just motors is available as a spare part which is not expensive as long as camera lens and camera and gimbal pcb works still.

Links to other posts on this project:-

1 DJI Mavic Pro Salt water damage

2 DJI Mavic pro ESC test

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Mavic Pro ESC test

Carrying on my testing after getting hold of a insurance write off Mavic Pro Platinum that landed/crashed into the sea.

Now time to test the esc board and after much cleaning with fresh water and removing the salt deposits and then cleaning with switch cleaner any remaining residue .

I connected it up to start with a 18650 cell , as wanted to see if anything got hot or it drew a lot of amps.

All seemed fine and even the motor led came on.!

Then tested with a 2s 18650 pack and this time the dji start up esc tones came through.

Then a final test with the original mavic battery pack minus the battery pcb as thats history.

Apart from the startup tones, all 4 motors twitched as they should normally do.

One thing for sure, one of the motors has totally useless bearings as spining it in a small hobby drill attached to the shaft , its as noisey as hell the other 3 sound okay although will replace the bearings anyhow.

 

So hopefully this is a sign the esc board is possibly okay? Will be pretty amazing if it is after landing in the sea and then had its battery left in it and sat in a insurance office for god knows how long festing away.

Do wonder if this hit the sea after the motors had already stopped? as the mosfets on the esc seem to be okay. I would expect them to blow normally with motors running hitting water.

Also amazing the lipo which was reading 0.4 volts total when I got it and it charges all the way back up and seems to have decent life in it apart from 1 cell which after 2 days drops to 0 volts again, but other 2 cells stay put. Intresting as a test and nothing more, will never be used in flight again.

The gps board that I had plugged in was sending a charge to its onboard backup battery, but to see whether it actually survived will need the main board connected.

The fan motor, I already know works okay.

Next thing will no doubt be the main board and that was in the worst condition , as it has salt deposits all over it and has had lots of cleaning, especially to connectors which were badly oxidised. I dont expect this to work , but will test it anyways as long as I dont find any shorts on the boards first.

Links below to other posts on this project.

1 DJI Mavic Pro Salt water damage

 

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