SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
This thread is privately moderated by roballoba, who may elect to delete unwanted replies.
Old Aug 04, 2008, 01:05 AM
Go ahead... Build it to crash!
Fuegodeth's Avatar
Conroe, TX
Joined Apr 2007
2,640 Posts
Quote:
Originally Posted by Mark Wood
The original LipoSack. Made in the USA and available from Hobby Lobby, Tower Hobbies and many other fine hobby shops around the world.

mw
Aww heck, Mark... Just be happy it took them this long to copy it. Imitation is the most sincere form of flattery. Now that's common sense.
Fuegodeth is offline Find More Posts by Fuegodeth
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 09, 2008, 07:08 PM
Registered User
gpdno's Avatar
Tucson, AZ
Joined Jun 2008
230 Posts
This morning I was out flying my foamie. My 3C 500mah Lipo was attached by velcro to the underside of the fuselage. I have flow this plane and battery combination a couple dozen times and never gave it any thought. When I went to land the 3S charging plug was hanginh down and caught between the belly and the ground. The plug pulled off and the four wires shorted together! White smoke started hissing from the pack and it expanded to about double its size. Needless to say the battery is toast, but the plane is ok. Next time I need to make sure the charger plug is safely secured!
gpdno is offline Find More Posts by gpdno
Reply With Quote
Old Aug 10, 2008, 01:22 AM
Registered User
fly2bob's Avatar
United States, CA, San Diego
Joined Nov 2005
1,933 Posts
About HUCK 328's report;

on error 3 and 5;

1) I thought most esc's have a lipo cut off to keep you from getting the voltage of the pack below 3v / cell. (I guess if the cells were out of balance this could account for this.)

2) I thought most chargers have a 'end charge cycle' when the pack reaches 3.7v / cell. (Again see above) But wasn't the 5s already fully charged at 18.5v's?

Bob
fly2bob is offline Find More Posts by fly2bob
Reply With Quote
Old Aug 10, 2008, 11:55 AM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,028 Posts
2) The charge cycle ends when 2 things occur - A. The pack voltage is at 4.2V/cell and the current is less than ~100ma. The voltage will be at 4.2V/cell for quite awhile before the current drops to 100ma. The pack will charge at a constant current with a rising voltage till the pack voltage reaches 4.2V/cell and then the voltage will remain constant while the current slowly decreases till it reaches ~100ma at which time the charge cycle ends.

3.7V/cell is the nominal cell voltage.
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Aug 10, 2008, 10:08 PM
Registered User
huck328's Avatar
Chicago
Joined Jul 2004
170 Posts
My ESC is programmed to cut out when the pack hits 15 volts. Unfortunately, that's not always the same thing as cutting out when each cell hits 3v. With a battery where the cells are not matching perfectly, one or more cells might get down lower than 3v while others are above 3v for a total that is still above 15v total. For example, with a 5s battery, 2.7 + 3.1 + 3.1 + 3.1 + 3.1 = 15.1

My guess is that - because the pack that blew up had less than 10 cycles on it and wasn't broken in yet, it may have increased the chances that the cells acted differently and got way out of balance when I ran it extra close to 15 volts.
huck328 is offline Find More Posts by huck328
Reply With Quote
Old Aug 11, 2008, 01:29 AM
Registered User
fly2bob's Avatar
United States, CA, San Diego
Joined Nov 2005
1,933 Posts
Quote:
Originally Posted by hoppy
2) The charge cycle ends when 2 things occur - A. The pack voltage is at 4.2V/cell and the current is less than ~100ma. The voltage will be at 4.2V/cell for quite awhile before the current drops to 100ma. The pack will charge at a constant current with a rising voltage till the pack voltage reaches 4.2V/cell and then the voltage will remain constant while the current slowly decreases till it reaches ~100ma at which time the charge cycle ends.

3.7V/cell is the nominal cell voltage.
Ah

Bob
fly2bob is offline Find More Posts by fly2bob
Reply With Quote
Old Aug 29, 2008, 08:48 AM
Registered User
Joined Feb 2008
21 Posts
Oh yah , i have heard a lot of stuffs of those accidents , but that case was rare you see.
I mean liek why will the LIPO get on fire on teh own , it is surely the making error , not your freinds , cause all my lipo getting fired cases i heard was cause of extending charges on the battery.

--------------------------------
San Diego Home Insurance
sayad is offline Find More Posts by sayad
Reply With Quote
Old Sep 28, 2008, 03:44 AM
Registered User
California
Joined Sep 2008
4 Posts
why is first time so hot?
i fly helicopter honeybee
adn cant hold.
AmiricanRC is offline Find More Posts by AmiricanRC
Reply With Quote
Old Sep 28, 2008, 04:08 AM
like a rock!
gravityKills's Avatar
Finland
Joined Oct 2007
2,473 Posts
hehe HBK with stock motor is the hottest heli I know. I haven't seen one that didn't have brushed-motor-meltdown after five flights
wrong thread, though
gravityKills is offline Find More Posts by gravityKills
Reply With Quote
Old Sep 28, 2008, 04:47 AM
Registered User
California
Joined Sep 2008
4 Posts
Batery is hot to. so much no touch
AmiricanRC is offline Find More Posts by AmiricanRC
Reply With Quote
Old Sep 28, 2008, 06:04 AM
like a rock!
gravityKills's Avatar
Finland
Joined Oct 2007
2,473 Posts
get a brushless motor+ESC.
gravityKills is offline Find More Posts by gravityKills
Reply With Quote
Old Oct 20, 2008, 11:39 AM
RAPTOR REP
RAPTOR 3D's Avatar
GRANGER,INDIANA 46530
Joined May 2007
43 Posts
It will help to let it cool down!
RAPTOR 3D is offline Find More Posts by RAPTOR 3D
Last edited by RAPTOR 3D; Oct 20, 2008 at 03:15 PM.
Reply With Quote
Old Oct 22, 2008, 12:03 PM
Registered User
mtnmnstr's Avatar
United States, MS, Amory
Joined Oct 2004
1,412 Posts
I'm new to the electric world and have been apprehensive about getting into it because of the lack of knowledge about lipos. Well I edjmakating myself about them.
My company put out Battery recycling bins. While poking thru them looking for Nimh I found a puffy laptop battery. I took it to our safety guy and he had no idea about Lipos until I pointed him to this thread.
Memo time.

Good thread.
mtnmnstr is offline Find More Posts by mtnmnstr
Reply With Quote
Old Oct 22, 2008, 01:09 PM
like a rock!
gravityKills's Avatar
Finland
Joined Oct 2007
2,473 Posts
this might be of interest: We all know the videos, where LiPos burn like fireworks when overcharged. Now I disposed of an old LiPo, 2200 mAh 4s ZippyMax, and for the fun of it just short-circuited it. As might happen in an accident where the leads get damaged or a charger burns up (happened once).
It took a while to puff, then it started to belch smoke. Hello! You won't believe how much smoke fits into such a little LiPo.
And it smells... hard to describe. Lower layers of hell. Kids don't try this at home. And if you try it in the park, get away quickly, because someone will call the fire brigade.

Charging this size of LiPo in the bedroom while sleeping is maybe a bad idea, even if using a flower pot etc. Not sure about the sleeping person's chances to get out in time (most fire victims die from smoke poisoning anyway).
gravityKills is offline Find More Posts by gravityKills
Last edited by gravityKills; Oct 22, 2008 at 01:16 PM.
Reply With Quote
Old Oct 22, 2008, 03:14 PM
characters welcome!
Mark Wood's Avatar
United States, CA, Bear Valley Springs
Joined Feb 2000
26,422 Posts
If you still think it can't happen to you, check out the Survivor's Gallery on our website. These are just the few that allowed us to post the circumstances and pictures. The latest was only a few days ago.
There was also recently an ignition in a well-known hobby shop that we were informed of where a LipoSack prevented damage to the shop.

www.LipoSack.com

mw
Mark Wood is offline Find More Posts by Mark Wood
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Can Triton temp. sensor prevent Lipo fires?? duganderson Batteries and Chargers 27 Aug 27, 2014 06:26 AM
How Prevalent Are Lipo Fires? DLC Batteries and Chargers 32 Sep 27, 2009 09:46 PM
Lipo Test are in tallflyer Parkflyers 0 Aug 26, 2003 12:09 PM
Question How Lipo's are rated electron_head Batteries and Chargers 6 Jun 30, 2003 08:58 PM
UK E Zoners are real people.... tim hooper Electric Plane Talk 13 May 01, 2001 10:00 PM