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Salt water baths DO NOT WORK for lipo disposal

Old 11-07-2006, 02:16 AM
  #26  
Larry3215
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Originally Posted by ragbag View Post
Why are you thanking Fred?

He just told you to finish the job with SALT WATER!

"Let it sit for 24 hours (not until the water evaporates!) and you can dispose of the cells/pack in the trash. "

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I was thanking Fred for backing me up on the "not for discharging" part of the statement.

Actually, Fred and I disagree on the final step to slit the packs and put them in salt water.

I think its not only unnecessary, but somewhat risky to cut open a discharged lipo. Puncturing lipos is always dangerous. There have been several reports of puffed lipos catching fire when punctured. There is also a toxic hazard from the internal chemicals. I dont like the idea of opening the pouch and letting them out.

Once the pack is fully discharged they CANNOT cause any damage so there is no real benifit to opening them up - its all risk.

I prefer to recycle them instaed of haveing them go into the landfills. I have to drink that water just like you do.

Larry
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Old 11-07-2006, 02:22 AM
  #27  
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Originally Posted by Cyclops View Post
Well ,I may as well stir the pot up.

(A) A Lipo is a mixture of chemicals that can and do go into THERMAL RUNAWAY when short circuited or crushed to the point that the chemicals physically begin touching each other when charged.

That most would agree upon.

(B) Are there any chemical engineers that know for a absolute fact that a completly discharged cell will NOT go in to thermal runaway ?

That is a fact I have never see anyone back up with proof.

If (B) is true, all that is needed is a complete discharge.

Am I making this too simple ?
Yes, that has been demonstrated several times.

Fred Marks himself mentioned testing that in his post above. Once the cells are discharged there is no chemical energy available to cause a thermal runaway and they are not flamable.

Larry
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Old 11-07-2006, 04:24 AM
  #28  
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Originally Posted by ragbag View Post
Sorry to disagree, but the purist of water is an insulator or my instructors way back in 1955 were wrong. It is the impurities in the water, salt, that are the conductors. That is the reason to add the salt.

If you add water to a wet cell and it is not distilled it will short the plates in a lead acid battery.



>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>
All true, but I don't believe anybody here was thinking of aqua dest when we were talking about throwing lipos into water...:p
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Old 11-07-2006, 05:45 AM
  #29  
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I should make it clear to Matt and the rest of you that I did not start this thread to accuse anyone of anything bad.

I myself used to recomend using a salt bath to discharge lipos for disposal. I have done it myself several times. Thats how I was told to do it and many many people recomended that as THE way to discharge a bad pack. Its easy and its simple and it SEEMED to work. As far as I know JJ Hong of Kokam lipo fame was the original person to recomend this methode.

I just happed to discover that it didnt work on one of my packs. When I cut it open to see what the insides loked like it almost caught fire it got so hot. When I looked closer I discovered that all the positive tabs were gone.

Next time I had to get rid of a pack I tried the salt again and paid more attention. The SAME thing happened. Tabs gone and after 3 weeks in the salt the pack still had tons of energy.

At that point I remembered some of my highschool chemistry classes and galvanic corrosion on my boats - the light bulb went off!

Thats when I started the first thread linked above and did all the tests.

Now NO lipo manufactorors still recomend using salt water to discharge lipos.

I suppose its possible that in some cases it may possibly work (I doubt that very much), but why take the risk? There is no way to test if it worked except to puncture the pack and see if you get a fire.

If it DOESNT work, you are left with a pack you cant discharge to a safe level.

Im just trying to pass on a safety message about something I discovered that may just possibly save someone from having a fire.

Good luck!

Larry
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Old 11-07-2006, 11:59 AM
  #30  
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Originally Posted by Larry3215 View Post
I should make it clear to Matt and the rest of you that I did not start this thread to accuse anyone of anything bad.
Larry
I don't think anybody took it that way. Last time I checked, we lived in a free country...

In any case, you made some interesting points and next time I have to dispose a pck I will pay more attention as well.

Fact is that if you discharge your pack to zero (light bulb or resistor) you have a safe pack.

The question of proper disposal remains, however.

Some manufacturers, dealers and users say, you may throw them into regular trash - I have some doubts here.

Once a week a special garbage truck comes through our area to collect trash, which can be recycled. Batteries of any kind are not permitted!

There seems to be a lot of grey area....

BoKo
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Old 11-07-2006, 08:42 PM
  #31  
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Originally Posted by Larry3215 View Post
I should make it clear to Matt and the rest of you that I did not start this thread to accuse anyone of anything bad.

Good luck!

Larry
But you keep beating that same horse.

I wish I had at my disposal the pictures of thermal runaway that has happened in the communications industry.

And they weren't lipos, they were a common battery that is used in many lawn tractors and other small gasoline powered machines. Twenty four in a cabinet.

Blew the doors off the cabinets and did severe damge to the area. Not a falsh off, but a real expolsion. There is a difference.




>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>
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Old 11-07-2006, 09:07 PM
  #32  
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i post on rcgroups about this, a salt water bath took me about 3weeks to de-ionize a 3cell pack, it's a bad idea.

the water gets all blue cloudy stuff into?? and there is alot of gas given off.
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Old 11-07-2006, 09:19 PM
  #33  
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Originally Posted by ragbag View Post
But you keep beating that same horse.

<snip>

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>
If this horse would stop comming back I would leave it alone!

On average, once a day on RC Groups and on here or RCU I see a post where someone asks how to get rid of a damaged pack and someone tells them to toss it in a bucket of salt water.

Forgive me for trying to keep those folks from starting fires or getting someone hurt when they thought they were doing the right thing

Larry
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Old 11-08-2006, 12:36 AM
  #34  
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Just wanted to thank you folks for a civil discussion on a hot button topic.

Thanks!
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Old 11-08-2006, 01:11 AM
  #35  
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I am one of those suspicious guys, who lets others be firstest with the latest.

I hope I gussed right on starting to change over to SAPHION, LI-ION cells.

Please lie to me and say they are,

SAFE!!
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Old 11-08-2006, 01:21 AM
  #36  
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Default wanna see something really scary???!!!

I was doing some research on different battery sites to see their recommendations for disposing of lipos. The following instructions are for disposing of a 11.1v 1800mah LIPO pack!


"Discharge all cells individually to 3.0 volts per cell. The cells or packs may be warm or hot during this discharge process. After cooling, insulate the output terminals and dispose of your battery immediately. "


WHAT!!!!
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Old 11-08-2006, 01:39 AM
  #37  
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Cancell ALL vacations and leaves in ALL Fire Departments !!!!!!!!!!!!!!!!!!!!!


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Old 11-08-2006, 03:34 AM
  #38  
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Discharge all cells individually to 3.0 volts per cell. The cells or packs may be warm or hot during this discharge process. After cooling, insulate the output terminals and dispose of your battery immediately.
Thats almost an exact quote from the original PolyQuest instructions. Actually its not all that bad. 3.0 volts per cell resting voltage is very very close to zero energy in the cell and is probably safe enough. I prefer going lower just because Im paranoid about lipo safety

The statement about them getting warm is true. Lipos tend to get warm as they over discharge unless the discharge rate is a very low rate.

However, its possible to cause the pack to puff if the rate is too hi while deeply discharging. Then you have an additional safety issue with the puffed pack.

I have had packs I was disposing of puff even when the discharge rate was very low, so you need to be carefull. Sometimes packs just seem to puff for no good reason and they are extreemly dangerous once puffed. Dont poke them!

Larry

Last edited by Larry3215; 11-08-2006 at 04:00 AM.
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Old 11-08-2006, 04:20 AM
  #39  
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Originally Posted by Larry3215 View Post
However, its possible to cause the pack to puff if the rate is too hi while deeply discharging. Then you have an additional safety issue with the puffed pack.

I have had packs I was disposing of puff even when the discharge rate was very low, so you need to be carefull. Sometimes packs just seem to puff for no good reason and they are extreemly dangerous once puffed. Dont poke them!
Larry
Very true. A fellow I fly with almost every weekend hat a brand new TP 1320. After the first flight the battery was about twice as thick as normal. His Slowstick is not capable of over discharging those batteries.
We checked the voltage...8.5V
He got so mad and before I knew it he had drilled a nail through the pack into the next tree! Nothing happened!

I have seen Lipos going up into flames very violently, but I have no idea why my friend got away with it.

Seems to me things are not so clear cut after all.

BoKo
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Old 11-08-2006, 04:34 AM
  #40  
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Thats one thing for sure about lipos - there are very few things that ARE FOR SURE!

I have ripped open packs in crashes with nothing more than a few sparks. Others carefully poke a small hole and get a ball of flames.

Then there is your foolish and lucky friend

Larry
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Old 11-08-2006, 10:19 AM
  #41  
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Originally Posted by Larry3215 View Post
Actually its not all that bad. 3.0 volts per cell resting voltage is very very close to zero energy in the cell and is probably safe enough.
I sure as heck hope no one puts any of those in dumpsters in the response area of my Fire Department!

That is still a charged 9v battery sitting in a garbage can, dumpster, landfill or some rural garbage dump along the side of an old country road somewhere... baking in the hot sun, leaching out chemicals into our water supply...

somehow I do not think that is a good idea! I've been a Fireifghter for 25 years and I have seen fires start from a lot less than that...
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Old 11-08-2006, 03:53 PM
  #42  
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This is not very encouraging information.

What is your average Joe Parkflyer supposed to do with old/damaged LiPoly packs now? He's usually got a LiPoly CHARGER, no cycler or discharger, isn't electronically inclined, and couldn't solder his way out of a paper bag. He's not going to shell out a dime for a "battery disposal unit," if there were even such a product on the market, and now we know the salt water trick doesn't work.

You can't just "stick a light bulb" on the pack because you have to have a different bulb for every pack voltage and capacity. A generic 12V tail light bulb may draw too many Amps on small packs, causing an already fragile pack to possibly go into thermal runaway, or could take days to drain large packs.
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Old 11-08-2006, 03:58 PM
  #43  
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I agree on the chemicals in the environment aspect. I prefer to recycle them.

However, at 3.0 volts per cell resting voltage, there is essentially zero energy left in the cell in a lipo. Im certain you wouldnt even get any heat from a direct short of a large pack.

As soon as you put a load on them the voltage will drop to a volt or so and you will only get a few ma of current flow at most. Not enough to heat anything up.

Its important to note were talking 'resting voltage" and not voltage under load. At hi loads a cell taken down to 3.0 volts will bounce back up to 3.7 volts or so in just a few minutes. It will have some significal energy left in the cell. A cell taken down to 2 volts per cell under load will bounce back to over 3.

You need to be sure that the cell is at or well under 3.0 volts after sitting with no lkoad for several minutes. At that point its safe enough.

Still, I prefer under 2.

Larry
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Old 11-08-2006, 04:04 PM
  #44  
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Originally Posted by Matt Kirsch View Post
This is not very encouraging information.

What is your average Joe Parkflyer supposed to do with old/damaged LiPoly packs now? He's usually got a LiPoly CHARGER, no cycler or discharger, isn't electronically inclined, and couldn't solder his way out of a paper bag. He's not going to shell out a dime for a "battery disposal unit," if there were even such a product on the market, and now we know the salt water trick doesn't work.

You can't just "stick a light bulb" on the pack because you have to have a different bulb for every pack voltage and capacity. A generic 12V tail light bulb may draw too many Amps on small packs, causing an already fragile pack to possibly go into thermal runaway, or could take days to drain large packs.
I agree 100%. Its a real problem. Its also why the salt water bath thing keeps comming back and wont die. Its an easy thing to do and ayone can do it. Its really too bad it doesnt work.

Even after I have told the guys in my local Hobby Shop about this, they still tell people to use salt baths.


Lipos are not ready for prime time use by the electrically chalenged.

On the other hand, there ARE recycle centers that accpet lipos from laptop computers and cell phones. I know many of those are tossed out with sihnificant charge in them. Maybe those folks are used to handling dangerous batteries.

Larry
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Old 11-08-2006, 04:58 PM
  #45  
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That's the key Matt, Lipos are not for the electrically challenged...

but they buy them anyway...:o


I have only had 1 lipo I've had to get rid of, so far anyway, and I did the recycle thing. There is a battery shop near my home and I dropped it off there. Hopefully they did the right thing with it... whatever that is....
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Old 11-08-2006, 05:07 PM
  #46  
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Well,

could the packs be drop in another, 'better' solution, then salt?




or not, i just deep discharge then seal them in a bag and trash....



could just sort it and let it burn, in a safe place haha :P
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Old 11-08-2006, 05:10 PM
  #47  
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Originally Posted by firemanbill View Post
That's the key Matt, Lipos are not for the electrically challenged...

but they buy them anyway...:o


I have only had 1 lipo I've had to get rid of, so far anyway, and I did the recycle thing. There is a battery shop near my home and I dropped it off there. Hopefully they did the right thing with it... whatever that is....
Hey Bill, Maybe you could start selling ammo boxes filled with the foam you guys spray on jet fuel to put it out??
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Old 11-08-2006, 05:39 PM
  #48  
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Now theres a thought! Side project to feed the hobby fund!
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Old 11-08-2006, 06:11 PM
  #49  
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Originally Posted by firemanbill View Post
I sure as heck hope no one puts any of those in dumpsters in the response area of my Fire Department!

That is still a charged 9v battery sitting in a garbage can, dumpster, landfill or some rural garbage dump along the side of an old country road somewhere... baking in the hot sun, leaching out chemicals into our water supply...

somehow I do not think that is a good idea! I've been a Fireifghter for 25 years and I have seen fires start from a lot less than that...
Putting a 9v battery in the same pocket as your change isn't a very good idea either. Found that out YEARS ago when I first started doing maintenance but without thinking last week I pulled one out of a smoke detector and dropped it on my pocket and a minute later I had this strange burning sensation coming from my thigh region. :o
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Old 11-08-2006, 06:18 PM
  #50  
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DOH! Yup, I could relate a thousand stories of how someone said

"gee I didn't think that would start a fire"
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