Happy Atheist Forum

Getting To Know You => Ask HAF => Topic started by: Big Mac on June 20, 2010, 10:03:23 PM

Title: Magnet flashlight and Batteries.
Post by: Big Mac on June 20, 2010, 10:03:23 PM
I'm a bit curious. I have one of those shake lights that I plan on putting in my living room mail stand. I also store lighters and batteries in there. Do you think the magnetic device in the flashlight will hurt the bag of batteries?
Title: Re: Magnet flashlight and Batteries.
Post by: Tank on June 20, 2010, 11:56:53 PM
Quote from: "Big Mac"I'm a bit curious. I have one of those shake lights that I plan on putting in my living room mail stand. I also store lighters and batteries in there. Do you think the magnetic device in the flashlight will hurt the bag of batteries?

Almost definitely not. Says an ex-electronics engineer, but what's a 'shake light'?
Title: Re: Magnet flashlight and Batteries.
Post by: Big Mac on June 21, 2010, 05:46:33 AM
Quote from: "Tank"
Quote from: "Big Mac"I'm a bit curious. I have one of those shake lights that I plan on putting in my living room mail stand. I also store lighters and batteries in there. Do you think the magnetic device in the flashlight will hurt the bag of batteries?

Almost definitely not. Says an ex-electronics engineer, but what's a 'shake light'?

Essentially a flashlight that has a big slug of magnetic material in a tube with coiled copper wiring. You shake the damn thing and it charges up a small power cell that powers a single LED lit flashlight. The problem is you have to keep it away from electronics but I'm curious if it would affect battery cells.
Title: Re: Magnet flashlight and Batteries.
Post by: Tank on June 21, 2010, 08:08:05 AM
Quote from: "Big Mac"
Quote from: "Tank"
Quote from: "Big Mac"I'm a bit curious. I have one of those shake lights that I plan on putting in my living room mail stand. I also store lighters and batteries in there. Do you think the magnetic device in the flashlight will hurt the bag of batteries?

Almost definitely not. Says an ex-electronics engineer, but what's a 'shake light'?

Essentially a flashlight that has a big slug of magnetic material in a tube with coiled copper wiring. You shake the damn thing and it charges up a small power cell that powers a single LED lit flashlight. The problem is you have to keep it away from electronics but I'm curious if it would affect battery cells.
Ah! I know what your talking about now, I have one. The issue is the effect of electric fields on the torch. The torch itself is passive and will not harm things around it. The torch has a long coil of wire in it. If this coil is subjected to alternating magnetic or electro-magnetic fields it will produce a voltage (it's the principle the torch works by). The problem is caused when the coil is excited by an unplanned event, such as putting the torch next to a bunch of current carrying mains voltage cables. The fields around the cables will induce current flow in the coil in the torch. BUT! The level of the induced current will normally be bugger all. However there may be circumstances where these currents are significant and cause the coil to melt. This is probably an example of the manufacturer being over cautious in a litigation sense. Your batteries will not be effected be the presence of the torch nor the torch by the batteries as batteries do not create a fluctuating electro-magnetic field which is what would interact with the coil in the torch.
Title: Re: Magnet flashlight and Batteries.
Post by: Big Mac on June 21, 2010, 09:29:52 PM
Ah okay, I like to have flashlights and candles around the house in case the power goes out, that way I can easily get some lumens going if you get my drift.