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Old Nov 15, 2007, 09:37 AM
Registered User
Orlando Fl
Joined Apr 2003
100 Posts
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A123's dont catch fire? NO???????





I set my trusty 300C with a 15s 2p A123 pack on charge with a Schulze charger set at 15s A123 4.5 amp charge and went for a cup of tea.

About 30 minutes later a shout from one of my buddies had us all racing back to the trailer where smoke was billowing out.

I hurled the remains of the heli out and so the damage to the trailer was minimal but the heli is written off from the tailboom forward.

I have no idea what could have caused this fire, but now all my charging will be done outside or under very close supervision, including temp battery temp sensor.

Dont get complacent guys, things can still go wrong.
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Old Nov 15, 2007, 10:54 AM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,112 Posts
The zinger here is a fire with a supposedly thought of, fire proof system. It may not have been the A123's fault, but something happened which could have resulted in extensive damage depending on where and when it happened, fortunately, you were nearby and alerted in time to minimize the damage.

Your final comment says it all - "Don't get complacent guys, things can still go wrong." I think we need to be reminded of that every now and then.
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Old Nov 15, 2007, 11:12 AM
Engineer in training
johnrobholmes's Avatar
Columbia, Missouri
Joined Jun 2004
399 Posts
That is why I never charge my packs in my plane car or heli. Sorry to see your loss though.
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Old Nov 15, 2007, 11:26 AM
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Joined May 2006
849 Posts
Sometimes "freak" things happen with batteries that have no explanation.

On the other hand, if a charging voltage is applied to a cell when it's fully charged (4.2 v), it is pretty much 100% guarenteed to flame up, right? Out of all the flame incidents with lithiums, aren't 99% of them occuring during charging?

Old batteries are plane scary. The packs loose "capacity" with time and by damage. If you end up with a pack that has effectively uneaven cell capacities, the smaller capacity cells would be subject to overcharging before the charger detects the peak. That ='s fire.
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Old Nov 15, 2007, 11:52 AM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
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I charged a 4S A123 2300 mAh pack as a 5S packs by accident which resulted in cells being charged to 4.56 volts each. There was no damage done to the pack and it now has an additional 41 flights on it.

Thing is even if the cells them self do not flame the associated wiring and surrounding combustibles sure can.

The only fire I have every experienced while charging batteries for use in RC during the past 44 years was caused by a Nicad.

The old advise of not charging batteries unatended is still very good abvise and atleast with A123s this can be a very short length of time.

Charles
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Old Nov 15, 2007, 12:08 PM
Registered User
United States, NJ, Frenchtown
Joined Mar 2003
9,215 Posts
Could be any part of anything ?

Battery--charger freaked out-- leadwires shorted. Without a accurate finding, it is tough to lay blame.

USA DOD has had the cells abused in everyway possible, including being shot by bullets to cause a fire and came up with no problems. That is why they, LIFE PO4's, are going into so many new hybred electric cars and military vehicles.

Still, yours could be the 1 exception. I found many " Brand new rejects. " before I retired.
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Old Nov 15, 2007, 03:14 PM
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5 miles from the geographical center of Pennsylvania
Joined Aug 2005
2,144 Posts
Sorry about your loss.

But it confirms my idea that I'm going to treat A123's like lipos and never assume that they aren't going to vent explosively. Someone around here got an A123 cell to blow up.
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Old Nov 15, 2007, 04:20 PM
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Orlando Fl
Joined Apr 2003
100 Posts
This lot obviously got hot part way through the charge and something set fire to the cabin which is molded ABS, fiberglass and acrylic. The charger was still charging even though the heli was on fire so one side of the 2p pack was still good.

I am glad its a heli I was getting tired of and was about to sell, and all my other helis were outside. All the transmitters were in steel drawers so they survived, the fluorescent lights in the trailer came off worst. Clean up was easy, just wipe the soot off. Small mercies I suppose, it could have been a lot worse, the fire was just above 5 gallons of kerosene jet fuel and 3 cans of propane/butane gas.

The first guy in the trailer was a fireman, and as usual with those guys, caused more damage than he cured. He hit the heli with his CO2 extinguisher and blew a load of molten burning plastic into the plastic face of the aluminum walls. Thats not coming off, but as he helped clean the rest of it up, I let him off <G>
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Old Nov 15, 2007, 04:28 PM
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amherst,nova scotia,canada
Joined Nov 2003
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Quote:
Originally Posted by Unterhausen
Sorry about your loss.

But it confirms my idea that I'm going to treat A123's like lipos and never assume that they aren't going to vent explosively. Someone around here got an A123 cell to blow up.
I believe it was a dry blast though with no fire at all. At least in the one I read about. In this case I hope the causitive agent was not the 123 cells themselves. That unfortunatly is probably not going to be established one way or another. .Reality though suggests it was a good possibility.
A little more time will probably determine the true risk factor if any with these 123s.
On the otherhand caution is just being smart. I really hoped these could be charged in the plane safely.
I wonder if the loss might be recoverable from your home insurance? It was a loss of personal property by fire after all. No harm in trying perhaps. Find out how much increase in yearly premiums result from collecting a claim. No normal person likes to see an event like this happen.
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Old Nov 15, 2007, 04:48 PM
Permanently Banned
San Jose Ca / RSA flyer
Joined May 2003
8,030 Posts
If the ESC was'nt vented properly the output FETs will short out thru the motor and battery , thats what almost happened to my ECO 8 HELI after landing, saw SMOKE and quickly released the 3S 6000 mah tp LIPO

modified canopy with cooling louvers on the side

U must always provide adequate COOLING for the ESC in a HELI or plane

some people here at the " RANCH" remove the shrink wrap and heatsink plate from the ESC and COOL the FETs naked in the open, makes it pass more CURRENT also

when I did an autopsy on the JETI 40 amp , found a whole bank of FETs to the BL motor connector completely charred
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Old Nov 15, 2007, 06:28 PM
Registered User
Slovakia
Joined Apr 2005
3,386 Posts
I am sorry about the looses.
This i a warning to everyone, never leave any energy without supervision.. There is a lot of energy in 15s2p pack.
If I would guess, then internal fuse of one or more cells did activate and as they are causing short circuit to the subject cell, big voltage difference show up. Well, paralleled part was perhaps fully charged and ready to use its power, so, my quess is that huge currents may flown from one part of a pack into another.
Tell me please, A123 cells used in this heli, they were in paper or in white foil? If a foil, or something that can not sustain high temperature, was the only separator between conductive cells, multiple short circuits between cell bodies may occur consequently.
Second question please, each cell was paired to create 2p parallel packs, then build 15s series of that 2p units, or that was just two 15s packs connected into 2p parallel as whole packs?
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Old Nov 15, 2007, 07:13 PM
Registered User
Dallas, TX
Joined Jan 2005
2,169 Posts
I wouldn't blame it on the A123 cells right off. Since no one witnessed it. The A123 cells have alot of power in them and in a 15s2p configuration that can be enough energy to cause what happened if the output of the pack is shorted. That kind of power can burn wires up and cause a fire without the cells going up in flames until the fire burns the cells.
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Old Nov 15, 2007, 08:06 PM
24 yrs. of Aircraft flying
epoweredrc's Avatar
United States, GA, Rockmart
Joined Oct 2004
5,822 Posts
Quote:
Originally Posted by jh2rc97
I wouldn't blame it on the A123 cells right off. Since no one witnessed it. The A123 cells have alot of power in them and in a 15s2p configuration that can be enough energy to cause what happened if the output of the pack is shorted. That kind of power can burn wires up and cause a fire without the cells going up in flames until the fire burns the cells.
That is what I am thinking, Something shorted, where is the pics of the charger itself? i bet the wires on the charger shorted and caused a fire, I really do not belive the A123's would do that themselves.
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Old Nov 15, 2007, 08:20 PM
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Slovakia
Joined Apr 2005
3,386 Posts
I have took a brief look at the history posts of Peter.
http://www.rcgroups.com/forums/showp...3&postcount=44

Excuse me please, but I am sure that You would better search for much better charger, for all Lithium, even for nanophosphate A123, batteries.
Well, I know that it is a serious problem, even if money do not matter.. Even worse, I have never seen a charger that would fulfill the safety needs, for such big packs and huge charge power.
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Old Nov 15, 2007, 08:25 PM
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Joined Sep 2007
408 Posts
Man, what a shame, that was a nice looking heli. Just curious, how do the three rotor heads handle compared to the two? You`ll probably never know exactly what caused it. But if it was a shorted pack or wires, even packs much smaller than this are capable of melting some pretty healthy wires, and do it pretty quick too. Its amazing how much current these little batteries can produce. Be careful about throwing em around on the workbench with a bunch of screws and tools too, i melted a nicad pack i was building like that once.lol
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