HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Nov 25, 2012, 11:55 AM
Registered User
Joined Jun 2012
810 Posts
Discussion
lipo battery failure warning

Hi everyone.

I am currently using some slightly puffed old flight batteries to run some electronic systems on an FPV ground station. I am wandering how safe this is.

In terms of discharge, they are only experiencing a few tenths of a C, and if they do go up, they are not near anything flammable, so I'm not terribly worried about that.

But what I am worried about is during charge. I don't really understand what exactly happens in when a battery tries to go off during charging, hence this thread.

I know that at some point, if the battery is gonna go, it becomes a run-away reaction and all hope is lost, but the question is, when is this point in relation to the symptoms? Basically, if I am checking these things every minute, and suddenly, on one of these tests, the temperature is warm (like body temperature, say), so I unplug the battery, is this too late? Is it going to keep heating up and then go off? Or does the reaction only become run-away at too-hot-to-touch temperatures, and I can just let it cool off and charge it slower in future?

I am trying to figure out if checking temperature every minute or so so that I can catch it when it starts to warm up, will be good insurance against accidents, or if unplugging it as it starts to warm up won't necessarily stop it from going off anyway.

I hope my question was clear. But it's late and I'm tired so who knows

Thanks.
Nereth is offline Find More Posts by Nereth
RCG Plus Member
Sign up now
to remove ads between posts
Old Nov 25, 2012, 12:49 PM
Frankenstein recycled packs
rampman's Avatar
USA, AZ, Gilbert
Joined Jan 2006
8,579 Posts
If c didn't go up the charge rate will not change. IMO they will charge the same as long as they do not get hard.
Just always balance charge.
Rick
rampman is offline Find More Posts by rampman
Reply With Quote
Old Nov 25, 2012, 12:57 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
20,310 Posts
Self heating starts around 70 to 90C (158 to 194F) range and thermal run-away is underway. So if the pack has reached that temp internally, unplugging won't help. But, the pack will be ballooned at that time and the fact that something is wrong will be very obvious. From all the videos I've seen of overcharging packs, ballooning starts well ahead of ignition. If it starts to puff, stop the charge and take the pack outside for later discharging and disposal. BTW, most charging incidents are caused by overvoltage charging.

More info than you probably want but very informative.
http://www.nfpa.org/assets/files/pdf...rieshazard.pdf
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Nov 25, 2012, 01:13 PM
Registered User
Joined Jun 2012
810 Posts
Quote:
Originally Posted by hoppy View Post
Self heating starts around 70 to 90C (158 to 194F) range and thermal run-away is underway. So if the pack has reached that temp internally, unplugging won't help. But, the pack will be ballooned at that time and the fact that something is wrong will be very obvious. From all the videos I've seen of overcharging packs, ballooning starts well ahead of ignition. If it starts to puff, stop the charge and take the pack outside for later discharging and disposal. BTW, most charging incidents are caused by overvoltage charging.

More info than you probably want but very informative.
http://www.nfpa.org/assets/files/pdf...rieshazard.pdf
The problem is I'm not quite sure what the difference is between "it's starting to baloon" and the natural puffiness of these batteries. So would you say that I would be able to feel the temperature rise on the outside well before it got to 70-90 inside?
Nereth is offline Find More Posts by Nereth
RCG Plus Member
Old Nov 25, 2012, 01:21 PM
Registered User
United States, NJ, Frenchtown
Joined Mar 2003
9,016 Posts
Maybe you are very good at Russian Roulette.
cyclops2 is offline Find More Posts by cyclops2
Reply With Quote
Old Nov 25, 2012, 01:51 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
20,310 Posts
Quote:
Originally Posted by Nereth View Post
The problem is I'm not quite sure what the difference is between "it's starting to baloon" and the natural puffiness of these batteries. So would you say that I would be able to feel the temperature rise on the outside well before it got to 70-90 inside?
Go to youtube and search for 'lipo fire'. You'll see many videos of lipos puffing and burning. Here's one -
LiPo Battery Fire (4 min 7 sec)


Batteries can be bought for under $10. Is your safety worth that much? I wouldn't try to save a few bucks by using damaged lipos.
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Nov 25, 2012, 02:51 PM
WATTSUP.SE
Jocke's Avatar
Sweden
Joined Dec 2001
2,307 Posts
Its never natural or normal for any LiPo cell to puff or baloon, anyone saying otherwise is lying. If it expands even slightly, the damage is done and should NOT be used, there is NO miracle cure or fix, a LiPo cell that has expanded/ balooned is damage, the internal layers has been delaminated and the cell in now unstable with permanent damage to its internal structure. Its in this state never worth the risk of keep using the cell/ battery.

Normaly with a LiPo cell that is behaving as it should, with a built up internal pressure and an expanding cell, the aluminum pouch seal should rupture before the pressure is to high, when the seal rupture and the pressure is released, the cell gets soft and one might notice a sweet smell.
Jocke is offline Find More Posts by Jocke
Reply With Quote
Old Nov 25, 2012, 03:39 PM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,369 Posts
http://www.hobbyking.com/hobbyking/s...mpatible_.html

Snip


Quote:
-Thickness swelling during heavy load doesnt exceed 5%, compared to 15% of a normal Lipoly during heavy load.
So fact is HK is clearly stating that anormal ( non HK nanotechs) swell / puff / expand up to 15% while their nanos only expand 5%.


Charles
everydayflyer is offline Find More Posts by everydayflyer
Last edited by everydayflyer; Nov 25, 2012 at 07:23 PM.
Reply With Quote
Old Nov 25, 2012, 04:07 PM
Registered User
United States, NJ, Frenchtown
Joined Mar 2003
9,016 Posts
Sounds like........ partial rape. mostly dead ??

Stupid lies.
cyclops2 is offline Find More Posts by cyclops2
Reply With Quote
Old Nov 25, 2012, 06:21 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
20,310 Posts
All lipos expand and contract on charging and discharging. What's the normal amount? Got me. http://batteryuniversity.com/learn/a...stance_or_hype

These guys measured 4% after first charge and up tp 6% on subsequent charge-discharge cycles. http://144.206.159.178/ft/641/92454/1607530.pdf
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Nov 25, 2012, 09:13 PM
Registered User
Joined Jun 2012
810 Posts
I was hoping we could look at "time to failure" as a function of heat, rather than as a function of puffyness, just because the batteries are a bit puffy already so it is a bit harder for me to notice any gains compared to heat, as right now, they are not heating up at all during charging.

The real issue is, once I notice them heating up can I stop the charge and save the battery, or at least stop it from venting and then deal with it in a more controlled environment, or is it going to vent anyway? I think the most useful answer so far was the guy that mentioned that it doesn't become run-away till 70-90 degrees.
Nereth is offline Find More Posts by Nereth
RCG Plus Member
Old Nov 26, 2012, 05:34 AM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,369 Posts
Quote:
right now, they are not heating up at all during charging.
I have been a member here for years and when I first started posting about LiPolys heating during chargeing everyone said they do not heat during charging. This was back in the 6-10C discharge rated and 1C max. charging days.

I suggest everyone with LiPolys purchase a very sensitive and accurate temperature indicator and use it while charging their LiPolys and I am not speaking of the battery temp. probes which many chargers have. These are fine for Nicad and NiMH batteries but useless for LiPolys IMO..

Charles
everydayflyer is offline Find More Posts by everydayflyer
Reply With Quote
Old Nov 26, 2012, 07:05 AM
Registered User
Joined Jun 2012
810 Posts
Quote:
Originally Posted by everydayflyer View Post
I have been a member here for years and when I first started posting about LiPolys heating during chargeing everyone said they do not heat during charging. This was back in the 6-10C discharge rated and 1C max. charging days.

I suggest everyone with LiPolys purchase a very sensitive and accurate temperature indicator and use it while charging their LiPolys and I am not speaking of the battery temp. probes which many chargers have. These are fine for Nicad and NiMH batteries but useless for LiPolys IMO..

Charles
Ok I should rephrase, they are not heating up *noticeably* when charging.

The issue is, if they do heat up noticeably, can I just stop the charge, let them cool, charge them slower next time?

I think at this point the answer is yes, based on Hoppy's response.
Nereth is offline Find More Posts by Nereth
RCG Plus Member
Old Nov 26, 2012, 07:24 AM
Registered User
Barbados
Joined Jan 2011
1,783 Posts
I discard a lipo if it's not right,they are just too cheap and easily replaced.
The Tug is offline Find More Posts by The Tug
Reply With Quote
Old Nov 26, 2012, 08:03 AM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
20,310 Posts
Quote:
Originally Posted by Nereth View Post
Ok I should rephrase, they are not heating up *noticeably* when charging.

The issue is, if they do heat up noticeably, can I just stop the charge, let them cool, charge them slower next time?

I think at this point the answer is yes, based on Hoppy's response.
My response in no matter or fashion suggests that what you are proposing is safe or recommended. What you are proposing is dangerous and definitely not recommended.
hoppy is offline Find More Posts by hoppy
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Lipo Pack Failure - What Kind Of Warning Signs Are There? itsme2 Batteries and Chargers 5 Aug 15, 2011 11:12 AM
Data Complete Guide to Lithium Polymer Batteries and LiPo Failure Reports Jim McPherson Batteries and Chargers 925 Aug 21, 2010 10:48 AM
New Product Detecting main motor failures, saving your lipos and other feats- Battery Monitor SSG Scott Micro Helis 9 Jun 07, 2006 09:10 AM
A serious LIPO battery failure/design issue. NZNEIL Batteries and Chargers 18 Apr 28, 2005 01:55 AM
Alert LIPO-402 Wire Failure-WARNING MikeBanyai Batteries and Chargers 0 Jun 07, 2003 10:19 AM