Author Topic: Don't use magnets with li-ion cells! Dead-short danger!  (Read 33755 times)

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Offline 45/70

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #15 on: April 06, 2006, 05:05:28 AM »
Good or bad I still like the magnets.  As AW just pointed out, you have to realize what could happen and use them accordingly.

Dave
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Offline andrewwynn

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #16 on: April 06, 2006, 08:49:58 AM »
they are an ok 'stop gap' (pun intended) solution, but i would look for a more solid long-term solution.

-awr
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Offline Lips

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #17 on: April 06, 2006, 09:06:51 AM »
Are the magnets dangerous in a 2C Rop LE    (small hose being used as a spacer)
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Offline CY

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #18 on: April 06, 2006, 01:28:48 PM »
CY,

I am not selling the magnets like others. The magnets are provided free ( a courtesy gesture ) in case anyone would need them and know how to use them. The protected cells are protected from shorts like you what you show in your picture. I think you may like to edit the title to unprotected LiIon cells and NiMH cells to reflect the real potential danger. These industrial LiIon and NiMH cells all have flat tops for making packs and I am already working to make the button tops available ( 17670/17500 have button tops already ). I hope other LiIon dealers will do the same. AW
giving away or selling makes little difference. by giving away/selling magnets with li-ion cells, this implies that it's OK and safe to use magnets with li-ion cells. especially for flat top cells.

there's basically two safe solutions to this issue:

1. aply a dab of solder to circuit board to raise contact
2. find another brand cell that has a nipple tall enough to make contact with circuit board

Please note this is a recent problem. all li-ion cells with lone exception 14500 made contact with circuit board with no issues until recently. at one time I tried to purchase every new li-ion cell that was available. this is no longer possible due to all the news cells coming out.

China's factorys may have huge mfg capacity, but sometimes they don't have a clue about end use requirements. So when mistakes are made, inventory in the pipeline still needs to be sold.

use of loose li-ion cells for consumers is still in infancy. standards are still being sorted out. We the flashlight community are the  guinea pigs.


Offline arewethereyetdad

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #19 on: April 07, 2006, 04:57:03 AM »
CY,

I am not selling the magnets like others. The magnets are provided free ( a courtesy gesture ) in case anyone would need them and know how to use them. The protected cells are protected from shorts like you what you show in your picture. I think you may like to edit the title to unprotected LiIon cells and NiMH cells to reflect the real potential danger. These industrial LiIon and NiMH cells all have flat tops for making packs and I am already working to make the button tops available ( 17670/17500 have button tops already ). I hope other LiIon dealers will do the same.

AW

Pretty fair rebuttal.  I have always felt AW's services to be top notch, BTW.  I prefer his protected R123's over all other R123's.

Offline Kryosphinx

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #20 on: April 11, 2006, 09:42:44 PM »
Are the magnets dangerous in a 2C Rop LE    (small hose being used as a spacer)

If the battery is inbetween the two batteries, which are in the spacer, then no. The spacer acts as an electrical insulator to the metal wall. The anodization is also an electrical insulator, so you should have no problems  :)

Offline CY

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #21 on: April 12, 2006, 03:07:27 AM »
Are the magnets dangerous in a 2C Rop LE    (small hose being used as a spacer)

If the battery is inbetween the two batteries, which are in the spacer, then no. The spacer acts as an electrical insulator to the metal wall. The anodization is also an electrical insulator, so you should have no problems  :)
never count on anodization as an insulator

Offline andrewwynn

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #22 on: April 12, 2006, 03:20:49 AM »
especially when using bored out bodies!
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Offline Bullzeyebill

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #23 on: April 13, 2006, 02:55:03 AM »
I was having contact problems using a 18650 cell in a LionCub 168A body with my Chameleon, so I took a rare earth magnet disk, 1/16 X 3/16", centered it on the + end of the LiIon, and applied a small amount of loktite to the sides of the magnet.  It seems to be a good solution.  The magnet does not move.  I am reluctant to add solder to the circuit, so with the magnet holding its place, I think I am safe.

Bill

Offline CY

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #24 on: April 13, 2006, 03:38:02 AM »
bill, adding a dab of solder will not hurt circuit board

ernsanada

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #25 on: May 10, 2006, 09:42:14 PM »
bill, adding a dab of solder will not hurt circuit board

It is very easy to solder. Only takes a second once the soldering iron or gun is warmed up.

Offline AlexGT

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #26 on: June 22, 2006, 05:33:31 AM »
Thanks! After reading this thread I decided to add solder points to all my li-ions cells

AlexGT

Offline andrewwynn

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #27 on: June 23, 2006, 05:15:14 PM »
to a TEST case! i tried to put a solder bump on my AAA LiON and it killed it.. must have opened up the PTC.. 'cause immediately after soldering.. it reads zero volts :-(

awr
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Offline arewethereyetdad

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #28 on: July 19, 2006, 01:55:43 AM »
Don't add solder bumps to your li-ons either.  ;)

Offline 45/70

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Re: Don't use magnets with li-ion cells! Dead-short danger!
« Reply #29 on: July 23, 2006, 03:57:10 PM »
to a TEST case! i tried to put a solder bump on my AAA LiON and it killed it.. must have opened up the PTC.. 'cause immediately after soldering.. it reads zero volts :-(

Ha!  I always wondered why they say to "never" solder directly to Li-Ion batteries!  Never even thought about the PTC.  Duh!  :D  Protected or non-protected you've still got the PTC.

Thanks for sacrificing a Li-Ion AWR!  :thumbup:  I've allways thought I might try it anyway.  Won't now!  :)

Dave
Eveready Economy Bright Light w/PR4 and "Heavy Duty" batteries