[NSRCA-discussion] Lipo fire

[David Harmon]

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] On
Behalf Of Robert Green via NSRCA-discussion
Sent: Monday, June 13, 2016 10:15 AM
To: 'General pattern discussion' <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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