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Dec 08, 2004, 05:34 PM
1,1,2,3,5,8,13,21,34
Shortman's Avatar

My first Li Poly fire just happened!


Wow, well I got to say this was kinda scary.

I was discharging my Apogee 830ah 2S Li Poly on the Astro 109 at 1.25 amps. Well I was in the other room and decided to check up on it as it had been about 3 minutes. The discharge had 640mah out of it?! And the battery was puffed big time, I quickly unplugged it ran to the front door and threw it outside, I went upstairs to check the charger and it was fine, I came back downstairs and the battery was on fire. I am good, nothing hurt, but I am really curious why this battery (only cycled about 4 times) puffed at a discharge rate of 1.25?

WWill take some pictures right now.
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Dec 08, 2004, 05:45 PM
Registered User
rcplaneguy's Avatar
Quote:
Originally Posted by Shortman
Wow, well I got to say this was kinda scary.

I was discharging my Apogee 830ah 2S Li Poly on the Astro 109 at 1.25 amps. Well I was in the other room and decided to check up on it as it had been about 3 minutes. The discharge had 640mah out of it?! And the battery was puffed big time, I quickly unplugged it ran to the front door and threw it outside, I went upstairs to check the charger and it was fine, I came back downstairs and the battery was on fire. I am good, nothing hurt, but I am really curious why this battery (only cycled about 4 times) puffed at a discharge rate of 1.25?

WWill take some pictures right now.
I'm no electronic whiz kid, but it seems like 640 mah out of the battery in only 3 minutes is a faster discharge than 1.25 amps.
Dec 08, 2004, 05:47 PM
1,1,2,3,5,8,13,21,34
Shortman's Avatar
Okay I had to go run outside and make sure the lawn didn't catch fire or anything. Phew, luckily it has been raining for the past 2 days. Well here are some pictures. There is a hole in one of the cells, looks like where the battery first caught on fire.
Dec 08, 2004, 05:54 PM
Southern Pride
everydayflyer's Avatar
640 mA in three minutes would be 12.8 A discharge rate.
1.25 A DSCH rate for 3 minutes would be 0.0625 ma but none of that matters.
The good thing you caught it in time and now to try to figure what caused it to happen.

Charles
Dec 08, 2004, 05:56 PM
1,1,2,3,5,8,13,21,34
Shortman's Avatar
Another picture
Dec 08, 2004, 05:58 PM
1,1,2,3,5,8,13,21,34
Shortman's Avatar
Yeah and that's what doesn't make any sense. The Astro 109 can only discharge at its maximum 1.25 amps. So something doesn't seem right. I have a feeling that I could have accidentily plugged it in, after I was done discharging the other pack and it switched to charge, other then that it doesn't make sense. I got it out though lol, whew, my hand was burning for a second as I threw that battery about 30 ft from the house.
Dec 08, 2004, 06:06 PM
I Need help. Dont sell!
Any more info on this? I am not familiar with this charger but were all the settings correct for charging since the discharge mode could not go above 1.25a? The answers out there some where...
Dec 08, 2004, 06:07 PM
Southern Pride
everydayflyer's Avatar
Quote:
Originally Posted by Shortman
Yeah and that's what doesn't make any sense. The Astro 109 can only discharge at its maximum 1.25 amps. So something doesn't seem right. I have a feeling that I could have accidentily plugged it in, after I was done discharging the other pack and it switched to charge, other then that it doesn't make sense. I got it out though lol, whew, my hand was burning for a second as I threw that battery about 30 ft from the house.
Well I have not had a LiPo fire yet and I don't care if I never do,however I did have a Triton charger to catch fire in the area right under the fan. I have heard of this happening with a few others. Like you I caught it in time as I was in the room with it.

There is good reason for the advise(warning) to monitor batteris while charging and I guess discharging should be added also.

Charles
Dec 08, 2004, 06:17 PM
1,1,2,3,5,8,13,21,34
Shortman's Avatar
I wish when I pulled the battery from the charger that it would have left the settings, but it didn't. Here is what I am almost positive happened, I was discharging my other battery pack, It finished so stupid me put the Apoge 830 on, well this is now in a CHARGE mode (because in order to discharge on the Astro 109 you have to completely turn off the charger and plug the battery in before its on to initiate the discharge) well I didn't and I turned it up to 8AMPS charge rate! EEEEEEEK, this would explain the 640mah put INTO the pack. Needless to say, luckily I don't use that pack for anything (I was just going to cycle it again as it had been sitting for several months). Learned my lesson.
Dec 08, 2004, 06:27 PM
Registered User
AmpAce's Avatar
Sorry to hear about your battery loss. Thank goodness that was the only casualty!

I'm not familiar with the Astro 109, but is there any possibility that it could have been discharging at 12.5 amps, rather than 1.25? The 640 mah you mentioned would be about right for this rate over 3 minutes time.

AmpAce
Dec 08, 2004, 06:29 PM
Southern Pride
everydayflyer's Avatar
(because in order to discharge on the Astro 109 you have to completely turn off the charger and plug the battery in before its on to initiate the discharge)
---------------------
Actually I turn on (connect )charger set charge to minimun,connect battery then disconnect charger then reconnect charger to get 109 into discharge mode.
We all make misstakes . The only ones who do not make misstakes are the ones who do nothing.

Charles
Dec 08, 2004, 06:30 PM
Registered User
unbalanced prop's Avatar
Shortman.............Man, good thing you were in the house and checking your charger. Just goes to show that anyone can goof, and that it is really, really important to monitor charging AND discharging. Thanks for being honest with us as to the cause of the fire. You were starting to make me paranoid. I couldn't figure out what caused the problem from something like a small discharge.

Doug
Dec 08, 2004, 06:40 PM
It wasn't me...
DanSavage's Avatar
Quote:
Originally Posted by Shortman
(I was just going to cycle it again as it had been sitting for several months)
Sorry to read about this and glad there was no permanent damage done. This stands out enough that I want to comment on what you've written.

It's my understanding that LIPOs do not need to be cycled for any reason, even for something like sitting around for several months.

The LIPO manufacturers here on Ezone say that a LIPO only loses ~1% of their charge/month and at no time do they develop a 'memory' like nicads, so cycling does nothing here. TP recommends that if you're going to store a LIPO, then it should be done with the pack half charged.

Astrobob has written that the only reason he included a discharge circuit on the 109 was to determine total battery capacity and it should be used on a fully-charged pack.

IOW, discharging a LIPO pack with a charger, for any reason, is unnecessary. Besides, it's always more fun to discharge it with an airplane.

I hope this helps.

Dan
Dec 08, 2004, 06:44 PM
1,1,2,3,5,8,13,21,34
Shortman's Avatar
Yeah, I just heard though that you if you let a battery sit over several months that you will have to reform (breakin) the batteries again.

Its all good though, I am charging up my Thunderpowers right now.
Dec 08, 2004, 07:08 PM
Registered User
unbalanced prop's Avatar
Dan......Apogee recomends a "break-in" procedure of 15 cycles at no more the 7C discharge down to 3 volts per cell and 1C charge. It says to do this with a charger or flying. As far as I know, they are the only people recommending a break-in.

http://www.pfmdistribution.com/guidelines.htm

Doug


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