[NSRCA-discussion] Lipo fire

Mon Jun 13 10:23:47 AKDT 2016

-1

David Harmon

Sperry, OK

From: NSRCA-discussion [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Atwood, Mark via NSRCA-discussion
Sent: Monday, June 13, 2016 1:09 PM
To: Shulman Jason <justanotherflyr at gmail.com>; General pattern discussion <nsrca-discussion at lists.nsrca.org>
Subject: Re: [NSRCA-discussion] Lipo fire

So playing a little devil’s advocate here.

I hear a lot of talk about “not storing them inside” or “discharging any charged packs that don’t get used” and a lot of other prudent sounding advice, HOWEVER… None of it seems practical or even remotely in line with ANYBODY’s habits that I’m aware of. 

I fly a few times a week.  My batteries are charged, virtually ALL the time.  Right now I have 9 10s5000 flight packs fully charged sitting on the garage floor in hopes that I’ll get out of work in time to put up a few flights tonight.  If I do… I’ll come home and charge them so they’re ready on the chance I get to fly tomorrow.    

50% of the time,.. the charged packs are sitting in my van all day…so that I can go straight to the field from the office.   During contests, the packs also sit in the van over night, charged and ready to go the next day.  

Yes, I discharge in the fall when the weather starts to turn.  Yes, I never charge unattended (or at least modestly attended).  But I have a litany of small batteries, Rx packs and foamy packs that are in disarray in various flight boxes and various states of charge.  Bad habit?  Probably.

My point is that keeping these out of the house, or in a state of discharge isn’t logistically realistic for the active flyer.  Maybe that’s a stupid statement.   But I’d really like to discuss practical approaches to staying safer.    And old packs??  Probably the most dangerous?  I have MANY.  I destroy  the truly old, but there’s a grey area where they’re not too old to discard, but they’re in the “I’ll only use them if I have to” stage of life.  

I sort of like the idea of a Cinder block “cage” I could erect on the concrete floor of my basement.  It wouldn’t help the smoke, but might contain the actual fire should a pack decide to ignite just sitting around.     I’ve seen these packs “scoot” across a paved surface when they go off, so isolation is only good if they’re physically contained.  

Treating them like gasoline or black powder isn’t really analogous since neither is particularly volatile if left alone.   A Jim stated… it would be good to understand better what caused Roberts pack to decide to become a road flare.    

My somewhat nervous $0.02

-Mark 

MARK ATWOOD

o.  (440) 229-2502

c.  (216) 316-2489

e.   <mailto:atwoodm at paragon-inc.com> atwoodm at paragon-inc.com

Paragon Consulting, Inc.

5900 Landerbrook Drive, Suite 205, Cleveland Ohio, 44124

 <http://www.paragon-inc.com/> www.paragon-inc.com

Powering The Digital Experience

On Jun 13, 2016, at 1:47 PM, Jas via NSRCA-discussion <nsrca-discussion at lists.nsrca.org <mailto:nsrca-discussion at lists.nsrca.org> > wrote:

Having seen the intense flames these batteries can produce, I'm not sure how the ammo boxes I've seen guys around here can withstand it if all the batteries went up one after another.

One thing I've always thought about is flower pots. They're fire treated so I can only assume that the flame wouldn't bother the pot any. Maybe?

Jas iP

On Jun 13, 2016, at 1:29 PM, David Harmon via NSRCA-discussion < <mailto:nsrca-discussion at lists.nsrca.org> nsrca-discussion at lists.nsrca.org> wrote:

Man….that’s a close call Robert.

Glad to hear that your wife handled this situation so well.

I use a 50 cal metal ammo box too….I used a 5/8” Greenlee chassis punch to make a hole on the back panel for a pressure relief. 

Hopefully the hole is large enough to relieve the pressure but still contain most of the flame.

Also….if I have any fully charged batteries after flying I discharge them to 50% (storage charge)…especially if I know they will not be used for awhile.

I use a 17 ohm 100W Dale power resistor, a short lead with the correct connector on it to discharge a 10S battery (connected to the main discharge battery lead)

This gives a 2.5A constant discharge rate which makes 100W of heat.

The resistor can handle that much heat but I put a small fan on it anyway.

I discharge them down to about 40% then put on the charger to bring back up to the storage charge.

This also balances the cells and makes the situation a bit more safe…..at least if one of them blows the energy is about half.

David Harmon

Sperry, OK

From: NSRCA-discussion [ <mailto:nsrca-discussion-bounces at lists.nsrca.org> mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Robert Green via NSRCA-discussion
Sent: Monday, June 13, 2016 10:15 AM
To: 'General pattern discussion' < <mailto:nsrca-discussion at lists.nsrca.org> nsrca-discussion at lists.nsrca.org>
Subject: [NSRCA-discussion] Lipo fire

Hey guys wanted to let you know about an incident I had over the weekend that caused some high concern.  I flew four flights yesterday, then returned home.  I thought I would go back out later and fly three more, so I charged three more batteries.  The three batteries on was planning on using, were flown the previous day, and were not overly discharged.  I took my kids to the movies as my wife did not want to go, and that turned out to be the best thing for the family.  One of my 2014 packs decided that it no longer wanted to live and decided to catch fire all by itself.  I have always thought that the best time for these to catch fire, would be during the charge cycle.  This incident happened almost an hour after charging the pack.  Keep in mind that after I charged the pack, there were immediately put into my flight box for storage until I got back from the movies.  After I took them off the charger, the batteries did not see warm in any way, cool to the touch.  I have had these batteries for two and as far as I can remember - they where not damaged in any way.  Due to my wifes' heroic action, the house did not catch on fire like my toolbox did.  She brought them out to the drive way water on them to kill the flames.  I have been pretty cavalier with packs, leaving them out once they are charged and not putting them in something safe for storage....those days are done.  If this can happen to a battery sitting with a stored charge, I will not longer leave my house or family unprotected.  

I bought a safe yesterday, but apparently that may not be the best thing for them either as the battery give off a gas and they need to breathe.  In other words if you left them in a safe you may be creating a bomb scenario.  What I did was - several years ago, I bought a metal ammo case.  I removed 3/4 of the rubber around the case allowing for the exchange of air to occur.

If any one has any other creative ideas on how they store there lipos, please contribute to this thread as I think it is important as a community that we spread the message that this technology which has been proven to be safe for the most part also can be dangerous.

thanks,

Robert

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