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Old Dec 07, 2003, 04:54 PM
My cat up close
bipeflyer's Avatar
England
Joined Feb 2001
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Fried 2S ET700 Lipo pack warning

OK,I know others have found this before,but it just happened to me!
I use a spare room in the house to charge my batts. somewhere close by to keep an eye on them.

I had the pack on a steel surface to charge,but on this occasion,the charge leads melted,pulling the pack off,onto the floor.

Unfiortunately,other combustables were present,and started burning that too!
Luckily,I check preiodically during charging,and during this check visit,there it was,on the floor,4 inch flames reaching skywards.

I just doused it with the damp cloth I always keep by.Nothing left of the pack though.This pack has been in use on a number of occasions without problem.Not been crashed or anything.
The piece of dowel you can see is what I used to sift through the wreckage.

Anyway,be warned!! They CAN spontaneously combust,I know Li Po's are very popular on users of 3D models,so please take extra care,I know I will not leave the room next time I charge...

I'd love to know what actually causes this to happen.I had the correct charge rate on my SC2,selected the 2 cell jumper,and being paranoid,ensured I checked about 5 times before plugging it all in.Most puzzling indeed..

Matt
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Old Dec 07, 2003, 05:17 PM
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St. Louis Metro
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Have you tried charging another pack since then, with the same charger, to make sure the charger didn't cause the issue?

WJ
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Old Dec 07, 2003, 05:24 PM
My cat up close
bipeflyer's Avatar
England
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Read my mind! Yeah,I'm trying it now,fingers X'd it will be alright...

Matt
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Old Dec 07, 2003, 05:26 PM
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St. Louis Metro
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Hope it was a fluke.... But nothing happens "spontaneously". I tall occurs for a reason.

Either way, sorry for your loss.

WJ
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Old Dec 07, 2003, 05:41 PM
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Midland, Tx / W. Lafayette, Ind.
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Its weired how they can burst into flames, but when i try to make them blow up or flame i cant! I had a small Kokam cell that had one of the tabs ripped off, and i shorted it out, got a little spark but not much, then with a pair of welding gloves on i started stabbing it with an x-acto blade. Small sparks but nothing dangerous. I did all of this outside on the driveway, and was wearing a mask too.
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Old Dec 07, 2003, 05:59 PM
BOSS
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New Jersey (excl EWR), United States
Joined Apr 2002
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====then with a pair of welding gloves on i started stabbing it with an x-acto blade.====


WHY?!?!?!?!!
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Old Dec 07, 2003, 06:20 PM
My cat up close
bipeflyer's Avatar
England
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Well,good progress with the next pack so far,the LED's are dropping on the scale,indicating charging is taking place,I have the charger and battery right next to me,the battery is in a saucepan! (dry of course! )

I keep feeling the battery every couple of minutes,stone cold,no funny sounds etc.looks well.

All I can surmise,is that the other pack had in some way shorted out,it had a PCB board on it too,this pack has not.
Let's see how it goes.

No worries about the loss,at least the house is still standing,other guys have suffered bigger losses than me,so for that I'm grateful. Thanks anyway,I have 2 more ET 700's left,so still might get a test flight on my Ultimate yet tomorrow.
To say I'm paranoid now can only be an understatement, you just cannot be too careful with these things.
I have yet to suffer the wrath of my wife yet....Oh well!

One other thing,my beautiful new Ultimate now has tiny holes in places on the uper wing,caused by that large lump of blue foam burning up,and launching hot embers into the air...imagine what would have hapened if this pack was still in the plane when I charged it!
I'll fill you in on what happens with the charge later.

Matt.
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Old Dec 07, 2003, 06:35 PM
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Well, it was no good anymore, and i wanted to see for myself if they were prone to explode when punctured. They dont seem to explode unless they have been punctured and are put on the charger or discharged. It was a small cell to, i think a 560. It was all really quite safe.
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Old Dec 07, 2003, 09:02 PM
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Ive read all those threads when they were in process. As i said, i had already shorted it out for a while, so it didnt really have any charge left in it. And, as it was winter when i did it, i was wearing long sleeves, a coat, pants, and a full face coverage mask. And ive read that you are supposed to dispose of damaged cells by puncturing them and putting them in salt water.
Ive never been burned by anything before, and im the type of kid who plays with alot of flammable stuff, like spud cannons, lots of fireworks, etc. because im pretty carefull. I honestly dont think a little .5 ounce worn out battery has the C4-like capabilities people think they do. I do realize that they are a major fire hazard, which is why i keep all my lithiums in a steel toolbox when they arent in an airplane flying.
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Old Dec 08, 2003, 07:26 AM
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Essex, uK
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Ouch Matt!!!!! Glad to hear the house is still standing. Did your marriage survive the experience?

Can this happen when a pack goes out of balance?
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Old Dec 08, 2003, 03:15 PM
Eat, sleep and FLY
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Conway, Arkansas
Joined Dec 2002
436 Posts
Oops!

The attached phot is a Li pack that literally blew the end off of the battery while charging. My fault, I had the charger set for 3cells. Point is, stuff happens, be ready.

I love the Li pack. Great power, light weight, holds a charge, and is UNFORGIVING if not handled carefully.

These little gems should always be charged in a fire proof container with a lid. The pack in my photo propelled itself (like a small jet engine) off of the charging surface and onto my carpeted hobby room floor. Luckily, my fire alarm warned me that something was definitely wrong. My loss was isolated to some planes, carpet and and wall paint. Too close for comfort.

Now, when charging, they are in a pyrex cooking dish with a pyrex lid.

Be careful, they can bite the hand that feeds them......
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Old Dec 08, 2003, 03:22 PM
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Wow!!! Just another example of the need to keep them contained. Im working on adding leads to my ammo can charging box, so i can leave my charger in its box and just connect the ammo can to the charger, that way the battery will be completely contained if it goes off and will have no way to damage anything.
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Old Dec 08, 2003, 04:28 PM
ProBro #261
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Coogee, Australia
Joined Aug 2003
609 Posts
I make my own lithium chargers ($3), specific for each type of pack, one for 2s ET700 one for 2s ET1200 etc so there is never a chance that I can have the wrong setting. The only thing I have to worry about is any inflight damage or hangar rash that will cause a lithium fire.

Matt
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Old Dec 13, 2003, 10:59 AM
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Bipeflyer,

I am curious which charger were you using??



Ronster
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Last edited by rgood1; Dec 13, 2003 at 11:03 AM.
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Old Dec 13, 2003, 01:44 PM
Leave me alone!
Martin Hunter's Avatar
Kamloops, BC, Canada
Joined Feb 2002
15,106 Posts
I'm moving this to the batteries and chargers forum.

Martin
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