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Old Sep 28, 2003, 08:05 AM
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Walled Lake, MI, USA
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Matt, I don't think we should get hung up on any single part of the issue. But I do think that every part of the issue should be fully understood by as many people as possible. I suspect that there are probably many people here who've never owned a fire extinguisher, let alone used one. If it takes a lot of spraying to put out a fire, this is just another piece of data that everyone needs to fully comprehend.
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Old Sep 28, 2003, 08:12 AM
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A good rule of thumb for a Dry Chemical extinguisher is this: Once you spray it at all, it has to be recharged, so you might as well use it all.

Matt
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Old Sep 28, 2003, 08:57 AM
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Sorry to read this sad story. I too Am glad no one was hurt.
It would be a benifit to us all if the actual cause could be found.
Is the 626 rated for 320 watts output ?
Sorry for your loss Gary.
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Old Sep 28, 2003, 09:06 AM
luc
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France
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according to Schulze site, the max output is 275W...which comforts me in my previous email: stay far from the limit and you will be safe(r).
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Old Sep 28, 2003, 09:56 AM
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I'm supprised the maximum output wattage is not software linited on the Schulze charger. It is on my old Orbit Pro. You can select 8 amps into a 32 cell pack but it won't give it to you and it won't fry trying.
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Old Sep 28, 2003, 11:07 AM
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Quote:
Originally posted by MattLarson29
On a related note, the extinguisher pictured is suitable only for class A fires. A turbine model has a whole lot of flammable liquids in it, and using water is an invitation to spread the fire. Since almost all flammable liquids float on water, they will just run off downhill, happily burning atop their cushion of water.
Matt,
The Indian Fire Pump is kept on hand to put out the reciprocal fire that the crashed turbine may cause; grass and brush, not the kerosene fuel or lubricating oil.

Daren
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Old Sep 28, 2003, 02:11 PM
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Dayton, Ohio
Joined Apr 2002
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Class D Fire Extinguisher

See this site about metal fires...

http://www.ilpi.com/safety/extinguishers.html

You may need a Class D extinguisher???

Mike
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Old Sep 28, 2003, 02:27 PM
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Hastings, Hawkes Bay, New Zealand (Aotearoa)
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If the charger failed due to overloading of it DC-DC step up convertor I would expect the output voltage to drop, not go even higher.

Heather
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Old Sep 28, 2003, 02:36 PM
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Alberta, Canada
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How long ago was the balance of the pack checked? It seems to me that a 10S pack has a LOT of imbalance possibilities. Even with the charger set right it would still cause a fire if the cells were out of balance very much and 10S means it could be a big overvoltage on one of the cells.

The fact that the first started towards the end of the charging cycle really indicates to me that one or more of the cells was overcharged at the end probably due to cell imbalance in the pack but that will likely be impossible to determine.
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Old Sep 28, 2003, 02:52 PM
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I know those with lipo cells enjoy the benifits..of them and are trying to make it safe to use them.. the cells are pushed harder in chargeing and in usage then what they should be.. Now if these cells crap out on you while your child is near by gets flamed and burned or dies or the dog gets it.... and the loss of your home .. and then the wife leaves ya .. was it worth useing them.. ? who thinks lipo's are worth it? who puts faith in the hands of your chargeing and useage and the quality of the charger and lith cells? The bigger these cells are the bigger the bang .. the farther the flames shoot out .... you get the picture.. shame but these cells have caused more trouble in the last few years then nicads or nmh cells did when they first come out..
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Old Sep 28, 2003, 02:57 PM
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I may re-think the Astro Flight dedicated LiPO charger and just spring for a lab grade CV/CC power supply. LiPo's are here to stay.
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Old Sep 28, 2003, 05:40 PM
BEC
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Auburn, Washington USA
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Quote:
Bernard, supply is 115AH deep cycle marine battery.
Thanks, Gary. If that is your usual supply for the charger, that pretty much removes the line of thought I was wondering about.

Quote:
"... It will take rather more info to sort this one all the way out..."

BEC, we may never know.
Agreed. After all, we don't have the resources of the NTSB or anyone like that.

Quote:
If the charger failed due to overloading of it DC-DC step up convertor I would expect the output voltage to drop, not go even higher.
I'm not an EE - but that sounds logical. I suppose it would depend on what the un-regulated output of the step-up converter is - what you get if there's no software control of it.

Quote:
How long ago was the balance of the pack checked? It seems to me that a 10S pack has a LOT of imbalance possibilities. Even with the charger set right it would still cause a fire if the cells were out of balance very much and 10S means it could be a big overvoltage on one of the cells.

The fact that the first started towards the end of the charging cycle really indicates to me that one or more of the cells was overcharged at the end probably due to cell imbalance in the pack but that will likely be impossible to determine.
This sounds plausible as well..... though I've never had a pack this large and when I've checked my packs they've all been in balance within 0.01V on each cell.

In fact I just checked my two most-used packs (two 3s ETec 1200s) and they are, as I expected, within 0.01V cell to cell.

Quote:
shame but these cells have caused more trouble in the last few years then nicads or nmh cells did when they first come out.
This may or may not be true. One thing for sure - we all know about these incidents much more quickly than we could have in the early days of NiCds and Eflight, and there are many more of us flying electric than then (20-25 years ago). And there's no denying that once a lithium battery goes up the result is more dangerous. I have seen NiCd caused destroyed models and grass fires from either overcharging and short circuits. But NiCds don't just keep burning.....

edit: added results of checking two ETec packs Sunday evening.
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Old Sep 28, 2003, 06:07 PM
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I'd like to make one more post in this thread to hopefully gain a postive from this experience for the e-flight community. I'll never really know what happened,..if it was charger, battery pack,..etc. since everything is literally "toasted". Something we do know is that there is the POTENTIAL for real danger. What I'll freely admit I did wrong, and it was my own stupidity due to complacency,.. is that I left a lipo pack charging, basically unattended, and went out to the flight line to fly something else during the charge cycle, so there was a 10 minute or more lapse in monitoring the charge. Contributing factor was leaving the pack in the plane while charging. When I charge at home, it's in the garage and only while I'm out there to monitor. I'm guilty of becoming too "comfortable" with the technology and I didn't give it the same attention while at the field. That was very stupid of me. I hate that it cost me an aircraft, charger, pack, power system,..etc. worth a few thousand dollars,.. but the lesson I've learned is to NEVER leave lipo's charging unnattended. If I'd been watching them every couple minutes I'd have surely seen a puffed cell before the fire. I can only count my blessings that the damage was a model airplane, and not a person. If there can be any positive from this, let it be the shared knowledge regarding unnatended charging. Please, don't become as complacent (stupid)as I was.
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Old Sep 28, 2003, 06:22 PM
Master of the Wind
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well said GWRIGHT!
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Old Sep 28, 2003, 06:24 PM
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Herb's Avatar
Irvine, Calif USA
Joined Feb 1999
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Quote:
Originally posted by GWRIGHT
... Something we do know is that there is the POTENTIAL for real danger. ...
Thanks for stressing this point.
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