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Feb 10, 2012, 01:41 AM
Suspended Account
Quote:
Originally Posted by gravityKills
yea I toast mine under a halogen lamp before flying
http://www.ebay.com/itm/THERMIC-BOOT...item3f12cb2960

this is safer
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Feb 10, 2012, 07:11 AM
like a rock!
gravityKills's Avatar
won't work, not enough power.
The table lamp I use gives 50 watts, and even that takes quite a long time for large packs.
Feb 14, 2012, 08:26 AM
High Plains Drifter...
BattleDude's Avatar
Quote:
Originally Posted by tonytester
4.21 when just off the charger. also 3.79 when I quit flying.
one morning it was 19F batteries lasted only a short time I had them sitting on the porch I should put the on my pocket .
thanks
TT
I put mine under my armpit to warm them up to around 80F. Makes a huge difference. Just think about your car battery, does it perform well at cold temps? No it does not. All batteries hate to be cold while in use.
Feb 24, 2012, 12:10 PM
Registered User
Manchild's Avatar
Quote:
Originally Posted by BattleDude
I put mine under my armpit to warm them up to around 80F. Makes a huge difference. Just think about your car battery, does it perform well at cold temps? No it does not. All batteries hate to be cold while in use.
Not true for iron phosphate batteries. They don't give a hoot about cold.

Btw- interesting thread as there are billions of lipos deployed worldwide in cell phones and such. Fires are usually caused by carelessness and/or defective equipment.
Feb 24, 2012, 05:49 PM
The Sweet Aroma of Fuel
electricrc68's Avatar
Quote:
Originally Posted by Manchild
Not true for iron phosphate batteries. They don't give a hoot about cold.

Btw- interesting thread as there are billions of lipos deployed worldwide in cell phones and such. Fires are usually caused by carelessness and/or defective equipment.
cell phone lipos have protective circuitry in them whereas rc lipos do not.
Feb 24, 2012, 09:48 PM
Registered User
Manchild's Avatar
Quote:
Originally Posted by electricrc68
cell phone lipos have protective circuitry in them whereas rc lipos do not.
The protective charging circuitry in RC lipos are in charger. Cell phone lipos have charge protection circuity in the battery. Again, fires are caused by carelessness or defective products. RC lipos are not inherently more dangerous than cell phone batteries.
Feb 25, 2012, 08:38 AM
Space Coast USA
hoppy's Avatar
Quote:
Originally Posted by Manchild
The protective charging circuitry in RC lipos are in charger. Cell phone lipos have charge protection circuity in the battery. Again, fires are caused by carelessness or defective products. RC lipos are not inherently more dangerous than cell phone batteries.
If you stuck a R/C lipo in a cell phone with it's protection from mechanical/electrical problems I would agree with you.
However, R/C packs are not:
1 - Protected from physical damage like a cell phone battery.
2 - Protected from over discharging like a cell phone battery.
3 - Protected from over current discharging like a cell phone battery
4 - Operated at a 0.1C(+/-) discharge rate like a cell phone battery.
5 - Protected from shorting like a cell phone battery.
6 - Temperature fused like a cell phone battery.
7 - etc
Feb 25, 2012, 10:52 AM
Registered User
Manchild's Avatar
Quote:
Originally Posted by hoppy
If you stuck a R/C lipo in a cell phone with it's protection from mechanical/electrical problems I would agree with you.
However, R/C packs are not:
1 - Protected from physical damage like a cell phone battery.
2 - Protected from over discharging like a cell phone battery.
3 - Protected from over current discharging like a cell phone battery
4 - Operated at a 0.1C(+/-) discharge rate like a cell phone battery.
5 - Protected from shorting like a cell phone battery.
6 - Temperature fused like a cell phone battery.
7 - etc
All of what you list is mostly carelessness or a defective product. Btw I've seen some cell phones discharge up to 1000ma depending on distance from cell site.
Feb 25, 2012, 11:35 AM
like a rock!
gravityKills's Avatar
>> RC lipos are not inherently more dangerous than cell phone batteries.

that's total nonsense..
A cell phone LiPo will not deliver 100++ C peak currents when you short or puncture it. Few cell phone manufacturers would optimize their product so that it coughs out one horse power when you accidentally short it with your key ring in your pocket. Wonder why.

You'll find plenty of people around here who've tried to use cell phone LiPos for RC. It doesn't work, at least not if you demand performance.
Feb 25, 2012, 12:42 PM
Registered User
Manchild's Avatar
Quote:
Originally Posted by gravityKills
>> RC lipos are not inherently more dangerous than cell phone batteries.

that's total nonsense..
A cell phone LiPo will not deliver 100++ C peak currents when you short or puncture it. Few cell phone manufacturers would optimize their product so that it coughs out one horse power when you accidentally short it with your key ring in your pocket. Wonder why.

You'll find plenty of people around here who've tried to use cell phone LiPos for RC. It doesn't work, at least not if you demand performance.
I guess the thread should be called RC battery fires are real. People single out Lipo batteries as dangerous but shorting any RC battery is dangerous (except iron phosphate). Again, carelessness..
Feb 25, 2012, 03:37 PM
Registered User
mumblety-peg's Avatar
Manchild... what exactly is your point? What I mean is, why make this statement in a thread labeled lipo fires are real? It seems as if you are dismissing the dangers.

Iimplying that 100% of all lipo fires can be avoided by *human beings* seems a bit reckless.The existence of pencil erasers seems like fairly concrete proof that people do make mistakes.
Feb 25, 2012, 03:40 PM
Space Coast USA
hoppy's Avatar
Quote:
Originally Posted by Manchild
Not true for iron phosphate batteries. They don't give a hoot about cold.

.
LiFePO4 lose almost 25% of their capacity at 0C as compared to 25C as well as a noticeable voltage reduction at 0C compared to 25C.
LiCo chemistry cells show a loss of ~9% capacity under similar conditions.
Last edited by hoppy; Feb 25, 2012 at 04:06 PM.
Feb 25, 2012, 03:45 PM
like a rock!
gravityKills's Avatar
in a nutshell, the main problem with LiPos is that they don't fail gracefully when abused / overcharged. Usually it means some kid learns the hard way that they may ignite and set the curtains on fire.

If given the choice between catastrophic failure of either LiPo or Pb in my living room while I'm around, I'd choose LiPo any time. But that's a matter of personal taste
Feb 25, 2012, 05:39 PM
Registered User
Manchild's Avatar
Quote:
Originally Posted by mumblety-peg
Manchild... what exactly is your point? What I mean is, why make this statement in a thread labeled lipo fires are real? It seems as if you are dismissing the dangers.

Iimplying that 100% of all lipo fires can be avoided by *human beings* seems a bit reckless.The existence of pencil erasers seems like fairly concrete proof that people do make mistakes.
Not what I implied but ok. 100% is such an absolute statistic. I said fires are caused by carelessness as well as defective products. You can equate carelessness with mistakes, stupidity..whatever you want to call it. My point is the batteries are only as dangerous as the people who handle it. Bottom line? Handle with care and you'll be fine.
Feb 25, 2012, 05:45 PM
Registered User
Manchild's Avatar
Quote:
Originally Posted by hoppy
LiFePO4 lose almost 25% of their capacity at 0C as compared to 25C as well as a noticeable voltage reduction at 0C compared to 25C.
LiCo chemistry cells show a loss of ~9% capacity under similar conditions.
False. This is one of the reasons why iron phosphate batteries are used in EVs. 25% loss at 0 Celsius wouldn't meet EV capacity standards. I predict iron phosphate batteries to replace all current form of rechargables in the future due to it's safe/stable chemistry as well as the operating temperature range as well as it's competitive weight.


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