[NSRCA-discussion] Li-Po Battery disposal - Best way

Mon Apr 18 07:09:25 AKDT 2016

The salt water bath approach has been floating around for quite some time, however, there is a possible issue with this approach.  Here is a section of an article from a club newsletter describing the possible issue.  

YMMV
Don

SaltWater Bath.... NO!!!

Therehas been a discharge approach for lipos floating around the internetfor quite some time.  Somehow, it just won't die and go away so we will cover it here and maybe help someone reading this that thinksthis will reliably discharge a lipo.  Notice I said 'reliably'.  Thesalt water bath approach 'might' work but there is no easy way tocheck whether it worked or not and you might be disposing a lipoyou think is fully discharged but isn't.

Thetheory.....  Pure water will not conduct energy, in fact has almostinfinite resistance.  BUT, add some chemical like salt and it willconduct current very well.  So, if we take water and add salt to it,drop a lipo pack in the salty water it should gradually/safelydischarge the lipo to zero voltage over time by allowing current toflow between the positive and negative leads of the pack.  Soundsgood, right?  Theoretically it should work... BUT it ignores thefact that the salty water will also cause a oxidation/corrosionprocess to occur as the energy flows across the connectors of thepack, including the aluminum connectors inside the pack.  Over time,this oxidation/corrosion process eats away at the aluminum of theinternal connectors of the lipo gradually dissolving it.  Now, assoon as this process erodes the connector(s) to the point there is noconnection between one or more of the cells of the lipo it will openthe circuit and you will get a zero volt reading when you check thepack using the main leads.  You can't see the internal connectors soyou have no idea the reason you are getting a zero voltage readingexternally is there is an 'open' in the internal circuit of the lipopack.  Of course, this might not occur and the salt water bath wouldbe successful but you have no way of determining if it was actuallysuccessful without opening the pack up to verify each cell is zerovoltage.  So, that is the reason you shouldn't rely on the salt waterbath to discharge lipo packs.

-----Original Message-----
From: Jay Gerber <jaysgerber at earthlink.net>
To: 'Terrence Walker' <tewalker10 at yahoo.com>; 'General pattern discussion' <nsrca-discussion at lists.nsrca.org>; atwooddon <atwooddon at aol.com>
Sent: Mon, Apr 18, 2016 6:39 am
Subject: RE: [NSRCA-discussion] Li-Po Battery disposal - Best way

For whatever it’s worth….If you can’t get to a battery disposal facility like Lowe’s, etc…..

I have discharged batteries using a glass bowl (not metal) filled with a concentrated salt water solution.  2- 5S 5400 ma Lipos took about 2 days for them to get to 0.01 volts.  Yesterday I discharged 2 4S 2200 Lipos in a day to 0.00 volts with the same process.  No danger, just let them sit and maybe refresh the solution for the bigger batteries.  Leave a little longer and they will go to 0.00 volts

Strip the leads staggered and watch that the positive lead doesn’t get caked up in a day or so.  It’s neat watching the bubbling taking place as the “electrons” flow out of the packs.
Jay

From: NSRCA-discussion [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Terrence Walker via NSRCA-discussion
Sent: Monday, April 18, 2016 12:44 AM
To: atwooddon at aol.com; General pattern discussion
Subject: Re: [NSRCA-discussion] Li-Po Battery disposal - Best way

Hello Don,

Long time no see. So I have an old 5000 10s flight pack that I want to fully discharge. How can a single 12v taillight bulb discharge this flight pack?

Enquiring minds want to know ...

Terry 

From: atwooddon--- via NSRCA-discussion <nsrca-discussion at lists.nsrca.org>
To: ldiamond at diamondrc.com; nsrca-discussion at lists.nsrca.org 
Sent: Saturday, April 16, 2016 6:44 AM
Subject: Re: [NSRCA-discussion] Li-Po Battery disposal - Best way

The process I use is to fully discharge the pack using a automotive tail light bulb, strip the mail leads back a couple inches and twist them together then dispose of if in the trash.  Fully discharged, lipos pose no environmental dangers.

Don

-----Original Message-----
From: Larry Diamond via NSRCA-discussion <nsrca-discussion at lists.nsrca.org>
To: 'General pattern discussion' <nsrca-discussion at lists.nsrca.org>
Sent: Sat, Apr 16, 2016 6:24 am
Subject: [NSRCA-discussion] Li-Po Battery disposal - Best way

I have a LiPo 5s 5000mAh pack that has a dead cell (1.6v).

What is the best way to dispose of this battery?

Larry Diamond

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