Two Cell Lipo looks like a pillow now

On Sat, 19 Nov 2005 03:17:17 -0500, "Ed Cregger"


I don't think it's a panic - just a healthy respect for the proper care and feeding of the little buggers. I heard very similar thing about NiCds when I got my 1st Kraft radio back in the mid 70's. (Which still works, but is on an illegal frequency)
I don't own any LiPos (yet - my b-day is Tuesday and lots of RC goodies were on my list) but I've been reading up on 'em because I *AM* going to convert this PT-20 my son and I are building to brushless/LiPo power.
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Who is in a panic? I certainly haven't seen any panic.
--
Paul McIntosh
RC-Bearings.com
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Say good night, Gracie. <G>
Ed Cregger
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Ed,
Perhaps 'panic' is the wrong terminology.
I think there is a cause for concern when charging a Li-Po pack because there is a possibility for catatrosphic failure of the cells -if they are not charged properly-. Similar things can happen during discharge(pulling too many amps) but I think the risk of a failure in the model while it is in the air is far less threatening than the risk of having a fire in the house while charging the pack.
The bottom line is, anyone with even a modest amount of common sense will understand the limitations of li-po technology and the fact that they must be treated with respect to avoid a fire. Unfortunately, with our current crop of blood-thirsty product liability lawyers the people who make li-po's need to cover their own ass and ensure that the proper warning labels are in place so they don't sued when an idiot starts a fire.
Chris
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On Sat, 19 Nov 2005 03:17:17 -0500, Ed Cregger wrote:

Fear of the unknown.
A 40 spinning an 11x4 at 10KRPM is a damned sight more dangerous. But familiar to the point of contempt.
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On Fri, 18 Nov 2005 18:39:00 -0500, Ed Cregger wrote:

Ive never heard of a LIPO self ignioting with no cause whatosever either.
Would you leave a gallon of Nitro in the front seat of a car in 100F ourside temps and bright fierce sunlight?
Would you casually leave a can open lying on its side wilst you connected a spark plug,?
Would you dispose of a can of old fuel on a fire?
All these sorts of things have been done with LIPOS. And not surprsiningly, some have caught fire. The slightly greater danger is not only do they have the chemistry to enable them to bun, they also have the ignition mechanism built in. However it takes some sort of damage - physical or electrical - before they do. The safety record of cells in mobile phones shows you that it is not inherenet in the technolofgy for it to spontaneously combust. Something has to be done to them, no matter what teh dumb hicks say when it happens to them.
I have to say that the only battery FIRE I have had was with a shorted Nicad pack, and the only battery EXPLOSION I have has was an over charged lead acid on a fork lift truck that blew up the moment the starter was cranked...and the localised hydrgen blew it apart.
I have destroyed LIPO pack by leaving it up a tree switched on for 6 weeks. It puffed a little and died in peace.
The risks of LIPOS are by now well known, and the frequeincy of incidents is now well down..you hear more horror stories about fingers being ripped of in IC engine accidents than LIPO fires.
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wrote:

I guess christmas trees should be outlawed then. I'll bet there are more christmas tree fires than fires caused by LiPo batteries in a given year.
I've had a case of heli fuel stashed in my gargae for about 10 years now.. It has yet to self ignite...
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They aren't as bad as that, but they aren't as tame as other suggest. They are DIFFERENT than what you are used to (NiCds, etc). Once you learn the differences and the handling requirements, you should be fine.
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Paul McIntosh
RC-Bearings.com
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just remember to remove them from the model when charging and place them on something that wont catch fire

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