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Dec 17, 2004, 11:31 PM
Tee Sqaured
Thomas Manson's Avatar

My First scary lipo experience.


Hey guys.

I recently landed a job (finally!) at my local hobby store. On my first day there I got myself a new lipo battery, a 3S Kokam 700 for my new Himax powered Edge 540 3D.

I got the battery about 4 days ago, I took it to my High school a few times for something to do on my lunch hour. Around the back of the school, behind the gym, there is a small lake, or rather, I gigantic mud puddle :roll eyes:

Anyhow, since it had been raining for a few days the puddle was large as ever, in the middle it was over a foot deep. My new foamy Edge 540 (my own design) built up my confidence level in the week I had owned it. I couldn’t torque roll very well 8 days a go, now im getting pretty darn good at it I can hold a normal hover all day long, and I found it great fun to tail dip in this massive puddle, I knew I was asking for trouble though.

I managed a few good dips, then I brought it around and did it a few more times, I threw in a torque roll into one of the dips, to cool! I tried the torque roll again, Belly towards myself, the nose snapped to the right, and I added left rudder (wasn’t thinking) and it dove nose first into the puddle, completely submerging 4 servo's my RX, ESC, battery and Motor.

I grabbed the plane (soaking my shoes in ice cold, muddy water) and unplugged it, everything looked fine, I took it back to the Electronics lab. I was lucky enough to be accepted into a College course in common core electronics, and im only 15!

I quickly removed all the radio gear and grabbed the heat gun, I put it on a warmish temperature and spent about half an hour drying all the gear out. I plugged the ESC into the RX, and then plugged the battery in, I was greeted with a sharp hiss and a puff of steam, the water had shorted the connector and boiled. I quickly blew out all the water and tried again.

With two happy sounding beeps, my ESC came to life! I ran the motor up a few times, and it worked fine *whew!*

Then the hiss again, the connector steamed, then started smoking, I unplugged it quickly, but the connector continued to hiss, then I saw the heat shrink on the Kokam battery starting to burn and shrivel, I grabbed some wire cutters and quickly cut the connector off, I moved the battery onto the floor, which is fire proof, I left it in an open area of the classroom. Thank goodness I was the only one in the lab at the time.

I retreated to my workbench and continued drying out the Servo's. I glanced at the battery, and to my horror, saw it was rapidly swelling to the size of a grapefruit. I had a sinking feeling my brand new, $50 battery was doomed. I watched the swelling stop, a little puff of smoke, and then nothing. I sighed with relief, it may have been a loss of $50, but at least the battery didn't start a fire.

I continued drying off my radio gear, and after about 3 minutes, I hear another sharp hiss, I looked up, the battery blew out a stream of white smoke under great pressure, then;

KABOOM!

The pack exploded like a smoke grenade! The classroom was instantly clouded with a thick white smog that reeked of lithium metal, I panicked, I grabbed the fire extinguisher and quickly put out the burning battery, I opened all the windows and closed the classroom doors, the battery smoked heavily for another minuet and a half before tapering off, the heat of the fire can be judged by the fact that it singed the Ceramic tiling.

I replaced the fire extinguisher and kept a close eye on the battery for another 10 minutes, then I moved the still hot remains onto a sheet of metal and ran for gym class.

I returned and found the remains cold, I threw them away and left for home. I was lucky the pack didn't cause a worse fire,

This was my first experience with an exploding lipo pack, and I will say that it was quite enough to see once! I warn anyone who uses these batteries to use extreme Caution, I was lucky that the pack was on a fire proof surface; otherwise I could have burned the entire school down.

Watch those lipo's carefully!!!

Thomas
Last edited by Thomas Manson; Dec 18, 2004 at 11:57 PM.
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Dec 18, 2004, 12:47 AM
CSI
CSI
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CSI's Avatar
Thomas,
Very nice, well written account of what happened to you. I am glad to hear that you lost nothing more than your money...although that is bad enough. I am sure that your average schoolmate there would have absolutely no idea about lipo batteries, nor the danger they can be. They might be tempted to play with one that they found laying around...maybe while you are out of the room? Best keep those things away from the un-lipo educated while at school, not that you leave them around, but you never know what some classmate might do if they found one.
Anyway, I liked your story. A very good reminder to be careful...especially at Christmas time when some of us might receive new batteries as presents. I'm never that lucky, I have to buy my own!!!
Ken
Dec 18, 2004, 04:41 AM
Registered User
ronnath's Avatar
i agree with CSI, a well-written story. and an excellent warning for all of us with lipos.
Dec 18, 2004, 08:07 AM
Registered User
I have been hearing about exploding cell phones lately. I am assuming that it is this type of battery that is the culprit?
Dec 18, 2004, 08:16 AM
Got H2? Fuel Cell R/C Car
Keith43221's Avatar
Quote:
Originally Posted by Synthetic
I have been hearing about exploding cell phones lately. I am assuming that it is this type of battery that is the culprit?
Yes it is. Nice story thomas. No fire alarm?
Dec 18, 2004, 09:42 AM
Cal
Cal
Registered User
Cal's Avatar
Quote:
Originally Posted by Keith43221
Yes it is. Nice story thomas. No fire alarm?
....or sprinkler system ???
Dec 18, 2004, 09:57 AM
INDORUS EXPARAMINTO
SPEED-E-FLYER's Avatar
Once a pack starts to swell and get very hot it is too late.
Get it outdoor because you are about ready to have an eVENT WITH FIRE
I have had a qute a few flamage events. My work shops smells like JUYCY FRUIT
gum from all the ventings of cells.

I know another tempting thing to do is dry out your elect. components faster and try them out. But next time you might dry them out then wait at least a day or 2 to let all of the water evaporate. It's hard to wait but you would be better off letting them dry out for a couple days before you plug them in.



Good story Thomas.

Larry.
Dec 18, 2004, 09:58 AM
fly it like you stole it
akflyer's Avatar
Quote:
Originally Posted by Synthetic
I have been hearing about exploding cell phones lately. I am assuming that it is this type of battery that is the culprit?
The Cellphones use Lithium Ion batteries. They are metal cased and much more apt to explode than lipoly's.
Dec 18, 2004, 10:04 AM
Registered User
Do you suppose with all of the different types of cell phones now days that people are just "grabbing" a cell phone charger whether it is for their phone or their brother or sisters and that inturn is causing a problem between the charger and the battery?
Dec 18, 2004, 10:39 AM
Repair Specialist
Ken-Ohki's Avatar
sorry to hear of your loss, but glad nothing/nobody was really hurt.

Mistake 1 You broguht it inside,, Never bring a questionable lipo pack inside.

Mistake 2 You rushed to see if your gear survived, You should have let it sit for at least a day in a warm, prefurably arid ( dry air ) location. ( the rest of the flight pack, not the lipo ) A heat gun isnt great for drying wet electronics. it might surface dry them, but most components can trap water... Put a few drops of water on a table and see how long it takes a heat gun to evaporate it. then put a drop on the table and place a penny over it and see how long it takes to evaporate that.. You will see it really isnt a effective thing..

Mistake 3.. You tested questionable electronics with a lipo battery.. Not a good thing to do. as you found out. but what can you do besides Learn from it at this point.


Other then that.. I think you handled the emergency part of this situation very well, My question is,, Did the school find out? and what did they have to say about it?

Ken-Ohki
"I make things do what I want them too, The Hell with what they are designed to do."
Dec 18, 2004, 10:59 AM
INDORUS EXPARAMINTO
SPEED-E-FLYER's Avatar
Most of the cell phone and laptop batteries have charging and safety circuits built into them.

The outlet plug-in transformer just provides DC voltage @ X amount of amps.

Larry
Dec 18, 2004, 12:59 PM
Tee Sqaured
Thomas Manson's Avatar
Thanks for the support guys.

The school has hand activated fire alarms, it dose not have a spinkler system that i know of.

Since students offen fry stuff in the eelctronics lab, smoke from that classroom is pretty normal . Since only about half the students were in the school, no one realy payed any attention, i will report to the school that it did happin though.

As for Electronic drying, you guys are right, letting it sit would be a wiser idea, but i was in such a flap to see if my radio gear would work i totaly overlooked that fact. I will try anhd resist the urge next time.

The electronics lab is far from any doors to the outside, i would not have had time to get the battery outside fast enough.

Thomas
Dec 18, 2004, 04:01 PM
Registered User
Quote:
Originally Posted by Thomas Manson
The classroom was instantly clouded with a thick white smog that reeked of lithium metal
Good warning story to keep everyone alert about how dangerous Li cells can be if not handled properly. The line above sounds a bit imaginative, inasmuch as LiPo cells contain only trace amounts of lithium metal. But otherwise a classic tale of things that can go wrong.
Dec 18, 2004, 04:28 PM
1,1,2,3,5,8,13,21,34
Shortman's Avatar
Just out of curiosity, why in the world would you try to continue to run a battery after it has been submerged in water? Yes I know a receiver, servos, and the OTHER radio equipment can be salvaged but even messing with a battery that is now ruined from water is asking for it. I only say this because you could have had been much worse off. Your receiver, servos, esc, motor's life will now be reduced dramatically because the electronics inside the receiver and equipment will now get corroded and eventually stop working.

I am glad your alright, but please don't try and use a battery thats been submerged in water! EEEE..


Glad your alright!
Dec 18, 2004, 04:44 PM
Space Coast USA
hoppy's Avatar
I'm surprised the fire sprinkler system didn't activate.
oops, see you already answered that comment -
Last edited by hoppy; Dec 18, 2004 at 05:10 PM.


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