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Salt water LiPo disposal - bad idea, or really bad idea?

stay-fun

Helicopter addict
#22
You can always stick the connector in the salt water rather than the entire pack...
If you do that, you'll make a hydrogen-oxygen mixture (electrolysis of water, also known as water splitting), which is explosive. Please don't do that :rolleyes:
And indeed it'll stop working below a certain voltage, so it won't discharge completely.

As for the damaged pack: I concur with the ammo can (or any other strong metal case - only in the US these things are common, right? :p ) with a vent in it. At least you'll discharge it and know when it's dangerous, rather than just leave it for weeks not knowing what it'll do.
 

rcspaceflight

creator of virtual planes
#23
As for the damaged pack: I concur with the ammo can (or any other strong metal case - only in the US these things are common, right? :p ) with a vent in it. At least you'll discharge it and know when it's dangerous, rather than just leave it for weeks not knowing what it'll do.
I didn't know about the vent...

I know the metal military ammo boxes are common, but still. To me it's an "antique" that I happened to have. I don't want to ruin it by adding a vent. (I know that seems weird, but I'd rather accidentally ruin an "antique" with a LiPo battery fire than burn down the house.) Maybe I'll just buy a new ammo box (or similar) and add a vent to it. Metal tool boxes aren't that much either.

By "vent" do we mean to just drill a hole in it? Where is the best place to put the vent? On top to let the gasses out? Or will the flames shoot out of it too? Are side vents best?
 
#24
By "vent" do we mean to just drill a hole in it? Where is the best place to put the vent? On top to let the gasses out? Or will the flames shoot out of it too? Are side vents best?
Yes, it means drilling a hole (or holes) in it. You probably want at least a one inch hole and yes - flames may shoot out of the hole, so it's probably best to put the hole in the top. The best idea may be to put wire mesh over the hole so that it catches any sparks or bits of burning battery that may set fire to the surroundings.

Another option is to use a thick terracotta flowerpot, or the aforementioned cinder block.
 
#26
I personally like the idea of a cinder block and a bag of sand. Put the Cinder Block on a level part of your Driveway (out of the Sun would be good, if Possible) place the offending battery, connected to the Automotive Tail Light Bulb Discharger, in one of the holes of the Cinder Block and then, while keeping the bulb visible, covering the hole with a bag of sand. I really like the idea of an automatic fire extinguisher when dealing with Lipo's, whether discharging for disposal or charging for use.
 

Tritium

Amateur Extra Class K5TWM
#28
Not a method for city dwellers but my preferred method of rendering a lipo inert is a .22LR. Stand upwind of the battery and shoot it. IF it doesn't burn to practically nothing then drop it in a bucket of water (any water will do since we are not discharging the battery but rather reacting the exposed lithium with the water).

Thurmond
 

razor02097

Rogue Drone Pilot
#29
If I need to dispose of a battery I will follow what the manufacturer suggests. I am not a chemical engineer and I can not control the current draw of a light bulb. I would use a resistor instead. At least then the wattage will go down as the battery discharges.
 
#30
An incandescent light bulb is a resistor, and the current draw depends entirely on the voltage of the pack and the rated wattage of the bulb. If you have a 25W tail light bulb connected to a fully charged 3S pack you'll get about 2.5A discharge current - definitely a safe discharge rate for any LiPo. If you want to discharge a 4S-6S pack you'll need two light bulbs in series.
 

pressalltheknobs

Posted a thousand or more times
#31
If I need to dispose of a battery I will follow what the manufacturer suggests. I am not a chemical engineer and I can not control the current draw of a light bulb. I would use a resistor instead. At least then the wattage will go down as the battery discharges.

Problem is they don't...

HK battery notice..

"Dispose of batteries in the manner required by your city, state or country. In the event of fire a class D dry chemical fire extinguisher must be used"

As TJinTech points out in the link I posted...

"The most important part of lipo disposal is to make the lipo safe, safe to be crushed in a garbage truck or safe when tossed in the recycle bin. We do not want to pass off a potentially dangerous lipo to people that do not understand what it is or how to handle it. As such I believe we have a responsibility to make them safe before they leave our care. "
 
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razor02097

Rogue Drone Pilot
#32
Hobbyking is a distributor. Their battery notice is included in all of my orders even if I didn't order a battery. That is probably something their lawyers said to include because most of the cheap batteries they sell come with nothing.

Every instruction I've seen that is saying to use salt water says to discharge the battery first. Every post about salt water method failing I've seen did not discharge the battery first.
 
#33
Every instruction I've seen that is saying to use salt water says to discharge the battery first. Every post about salt water method failing I've seen did not discharge the battery first.
If you discharge the battery first, there is absolutely no need for the salt water bath. A fully discharged battery is safe.
 
#34
DUH!!

Many moons ago, before the white men killed all the buffalo I learned this lesson the hard way. a friend who only knew slightly more than I did told me about salt water and slashing. I've still got the scorch marks on my work bench.
 

mrwzrd59

Old Guy Geek
#35
Salty dogs...

Interesting but I've only done the brine kill three times and the lipo's came out deader than any doornail known to man.

I never even considered that the process was doing anything other than killing the chemical reaction that goes on inside the folds of the cells. I do remember back in chemistry class when we would place tiny slivers of lithium in a pan of straight water and watch the fireworks! Do the trick again in salt water and no drama whatsoever, just some fizz and done.

Perhaps we should be focusing on the ratio of salt to water??? I pour a whole container of Motron's table salt (I think it's equal to 20 oz.) into 3 gallons of water in a 5 gallon PLASTIC bucket and toss in the pack, leads & all.

Absolutely NO action happens, just tiny bubbles come up from a little trapped air, then nothing....Crickets....

As the water evaporates, it will leave a brine coating on the sides of the bucket and of course the pack comes out looking chalky if you just let it air dry.... I then cut off the leads, de-solder and reuse them. No issues ever.

Anyway, I had no problems AND none of the leads or tabs ever dissolved before the pack was dead after 48 hours. I did check one at 24 hours of soak and it was stone dead but if and when I do the burial at sea with another lipo, I'll let it soak for 48 hours or more. Of course my bucket sets outside on concrete, at least 5 feet from the garage and not under any overhang.

One has to wonder who was ever silly enough to recommend slicing open the pack??? Sounds perfectly nuts!

I totally agree with practicing great caution when dealing with these modern marvels of energy density because there's obviously some children and curious George's who just will not follow the rules because they MUST do things their own way!

I guess that'd include me! Safety First!
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#36
One has to wonder who was ever silly enough to recommend slicing open the pack??? Sounds perfectly nuts!
Read the original post. He explains the history of the idea. :)

I like the discharge with light bulb out back in the bunker then twist the leads together (recovering the XT60) and deliver dead to Batteries Plus approach.
 

RichSam

Junior Member
#37
Salt Water method

My question is what if you already cut the batter leads off?

I discharged the battery with my charger, the promptly cut the terminals off at uneven lengths to keep them from possibly touching.

Can I still take these to a disposal facility?
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#38
My question is what if you already cut the batter leads off?

I discharged the battery with my charger, the promptly cut the terminals off at uneven lengths to keep them from possibly touching.

Can I still take these to a disposal facility?
I take mine to Batteries Plus Bulbs. They will take them with the terminals removed charged or not.
 

tmack

New member
#40
I discharge with a DC lightbulb. I had one 3S that was old and severely puffed. So I drove a nail in it after I discharged it with the light bulb and it was dead, no fire works. None of the packs I have discharged have puffed up during discharge like that. Salt water is a waste of time. Better to run it out with a light bulb.