stunthanger.com
Electric Stunt => Gettin all AMP'ed up! => Topic started by: John Hammonds on October 19, 2009, 02:26:30 PM
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A rhetorical question really, I'm more interested in disposal of old Lipos. What sensible precautions should I take when disposing of an old (Possibly unstable) pack. The local waste site has an area for old batteries, everything from automotive through to AAA duracells and I'm sure they would say "Just chuck it in there" (Next to all the lead acid batteries etc). I'm not comfortable doing that unless someone who knows Lipos tells me it's OK.
The reason for the title is 3rd corner of a square loop and the plane made the turn (Well most of it did), The battery plummeted into the ground and the outboard wing fluttered down behind it. :-[ My own fault, I moved the battery location into the wing to solve a vertical CG issue and was pretty dumb about it. My Streak effectively has the battery box fixed to the fuselage with the wing attached to the fuselage and battery box so although the wing is still supporting the weight of the battery (It's part of the model all up weight). The weight is not quite so "localised". Is that the right word?? The Buster being an afterthought I stupidly built the battery box into the wing itself with predicable results.
The Lipo was squashed and bent through an angle of about 15 degrees and is currently on the patio in a tin box with a few house bricks on top waiting to see what happens. How long should I leave it? On the off chance nothing happens and voltage readings etc measure up would it be worth trying to charge it, (In a wide open space inside a Lipo Bag). If so trickle or 1C rate?
Thanks in advance
TTFN
John.
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The link below will tell you all you need to know. y1
http://thunderpowerrc.com/PDF/DISPOSAL-OF-LIPO-BATTERIES.pdf
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Excellent, Thanks Rudy, No exotic materials I like it. Even I can manage salt water and a bucket of sand. :)
That link should be in a sticky, I'll bet a lot of future ECL sport flyers (And RC flyers) would not give proper disposal a 2nd thought.
Thanks again.
TTFN
John.
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Hello John,
Rudy's advice is excellent, but no fun at all.
Disposal Technique
materials needed:
1) large concrete patio with no flammable objects anywhere nearby or above,
2) long 2 X 4 with a nail in the end
3) video camera
4) safety glasses (a concession)
You can figure out what everything is for!
Dean
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Since John's batteries have been so severely traumatized (smashed and bent) is it POSSIBLE that they have already been rendered inert?
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The title of this thread does have some merit.
If you could figure out how many "G's" your model is pulling at the apex of an inside corner (or outside also), then multiply it times your battery pack weight and build your battery compartment accordingly...I betcha we'd be talking "pounds".
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If you assume 80 ft/sec speed and a turning radius of 10 ft, the g load would be 20 g for the turn plus 1 more for standard gravity (at the bottom), or 21 g in total. An 8 oz pack would put over 10 lbs to the structure.
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Hi Dennis,
In all likelihood, no. If there was any internal shorting, the vents-with-flame show would have happened shortly after the ejection.
I once saw a 5S, 5 amp-hour pack eject from a Pattern plane (the flyer no longer uses velcro of any kind!) and it fell maybe 200 feet to soft sandy soil. It was bent maybe 5 degrees in the middle. We watched it for an hour. Then ran a discharge/charge cycle out on the field. Then he flew it another 30 flights before it started to loose capacity fairly quickly. Then it was properly discharged and disposed of.
later,
Dean
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An 8 oz pack would put over 10 lbs to the structure.
While a 5 oz fuel tank would manage only about 7 lbs 8)