The sea is surprisingly warm but also was pretty murky yesterday. This happened 500 feet from home so marking the spot was impossible. 30 minutes in up to my chest failed to find anything.
Took the dog out in the pouring rain this morning. It was low tide. Walked the shoreline looking for pieces of plastic. When the aircraft decided to lose battery power and go in the tide was going out, where it sank is toward the harbour mouth whee flows can reach seven knots. It was nothing like that yesterday, probably a knot and a half.
Against logic I walked toward the crash site, against the flow of the water yesterday. Propped against the beacon pole (top left of the picture) was the aircraft!
The dog got a short walk. The Inspire is currently in a water bath. What do I do next?
The battery has swelled but managed to get it out. It’s currently sitting under fresh water. I’m wondering how to dispose of it safely, I’m concerned that if it dries out it may decide to warm itself a touch violent;ly.
As for the aircraft I’m changing the water regularly and slowly stripping down what I can. Certain parts are already showing corrosion. Some of the socket head screws don’t seem to be standard sizes
The only physical damage apart from the battery appears to be a slightly bent prop. I’ve also got the X% camera under water though whether anything can be saved is debatable.
As it’s already been for a dip, then create a salt water solution and allow it to discharge in a fire safe location. Probably take a couple of weeks.
Use 30 to 40g of salt for every litre of water. I recall reading that this approach is preferred for damaged batteries.
Thanks for that. Or I could tie a bit of string on it and lob it in the sea for a few days It’s finding the fire safe location that is the problem. Under water seems logical but I believe that can cause the problem, anywhere in the house is a no-no and I live in what is essentially a terrace with a small and overgrown garden. Don’t want that to catch fire!
For now I’ll wack it into a salt water solution in a bucket.
So you have a bad LiPo battery? No one really wants to keep them around (fire hazards that they are). So what is the process to get rid of a bad LiPo battery safely? Let’s go through it.
Discharge the LiPo battery as far down as you safely can . You can do this a number of ways. Most computerized LiPo chargers have a discharge feature in them. If you don’t have a charger with a discharge feature, you can run down the battery in your vehicle - keep in mind that you risk a fire and potentially damaging your vehicle doing this, so take care to have the necessary safety equipment around. Alternatively, you can build your own discharge rig with a taillight bulb and some wire. Simply solder a male connector of your choosing to the tabs on a taillight bulb, and plug the battery in. Make sure to have the battery in a fireproof container while doing this.
Place the LiPo in a salt water bath . Mix table salt into some warm (not hot) water. Keep adding salt until it will no longer dissolve in the water. Ensure that the wires are all entirely submerged. The salt water is very conductive, and it will essentially short out the battery, further discharging it. Leave the battery in the salt water bath for at least 24 hours.
Check the voltage of the LiPo . If the voltage of the battery is 0.0V, great! Move onto the next step. Otherwise, put it back in the salt water bath for another 24 hours. Continue doing this until the battery reaches 0.0V.
Dispose of the battery in the trash . That’s right - unlike NiMH and NiCd batteries, LiPos are not hazardous to the environment. They can be thrown in the garbage with no problem.
Not sure about No 4 but the process worked just fine for me on a duff Hubsan battery.
The battery shows no sign of life although it went down with some charge left in it - readings went from 60 to 30 in a couple of seconds immediately before swimming, Airdata shows battery at 54% at end of flight. The circuitry is presumably fried so I’ll need to carefully remove that befor getting a voltmeter onto the cells themselves.
Yeah, I knew it wasn’t you that had the first repair done as I know you haven’t had it very long.
Obviously the left arm gave that away for those that are unaware.
Oh no…gutted for you. You have an uphill battle ahead. If you were lucky it would have killed power when it went in. Can all the circuit boards be separated? If so then then a good clean deionised water to wash away any salt. Ultrasonic cleaner can help but will destroy any sonar sensors (remove if possible). All the shielding cans need removing as water and salt will be in there. When clean, dry and corrosion free try to power with a power supply with current limit set very low. As I said you may have been lucky but putting battery with an unknown short will make things a lot worse. Upload plenty of pics.
Odd sensation really. Panic as it suddenly announced it was dropping its landing gear, failed to prevent auto landing, looking more at the drone than the screen and disbelief as it disappeared soundlessly under the water with no spray or disturbance. Resignation was followed by the resolve to wade in and try and find it, a thankless task that achieved nothing.
I spent the night running “what if” scenarios through my mind and waking up at various intervals. Then joy as I found it this morning and a macabre sort of interest in dismantling a washing the aircraft.
I now have the corpse dismembered and wrapped up in rice filled plastic bags like some mad axe murderer.
One thing not clear in any of the instructions I’ve read is whether the bags should be fully sealed to let the rice absorb moisture or open to let the moisture evaporate as the rice absorbs it.
Thanks Mike. I would certainly have preferred not to undertake this exercise! From the looks and smell the battery circuitry fried itself, presumably early on in the underwater phase.
Nothing else looks remotely as damaged, on the electronics I can see there are no visible signs of shorts. The Inspire is a relatively simple design with a power distribution board in the battery compartment feeding juice to each motor via wires down the carbon arms. Each motor has its ESC mounted underneath with a short cable linking them. The flight controller / lightbridge stuff seems almost to be a sealed unit. The bulk of the fuselage is taken up with the undercarriage mechanism.
I’ve removed the motors and flushed the carcass several times. I’ve left some stuff separated but still coneected by cable as the joints are soldered. If you ever have to replace a landing led you will be frustrated at the tiny co-ax wire that has to be soldered to the lightbridge antenna when a simple plug would make changeover so much easier. That’s how they get people to use authorised repairers presumably.
Now I need to wait for several days before putting it all back together. I’m working on the premise that it was lost, never to be seen again. Turned up like a bad penny, with no sign of life. Anything working after being soaked in seawater swirled around in a bathtub and being worked on by a ham-fisted bush mechanic will be a major bonus,
Wish I could have been of help, but my days of grubbing around on the sea bed kitted out in an Avon dry bag and diving set are long gone. The mind may be willing but my joints called time on that activity years ago…
Just few words, in case of contact with normal water I would clean it with water from my dishwasher… As I have always plenty… That will remove ale micro elements and this type of water doesn’t transport electricity… And that can be dry in slow… I have rescue my phone like that… lost it in snow on car park, good ppl found it and after two weeks starts working till today.
It’s finding the fire safe location that is the problem. Under water seems logical but I believe that can cause the problem, anywhere in the house is a no-no and I live in what is essentially a terrace with a small and overgrown garden. Don’t want that to catch fire!
you can breathe life back into the beast and get it back in the air without too much grief or expense.