Battery + Magnets

[Rawk]

Greetings, can't find informative search results.
Can magnets harm batteries ?

I bought some strong magnet discs, the small one holds 2,4kg (~74ounces)
says the website. It holds my Nitecore very well, but i'm not sure about risks.
Can a magnet cause flashlight malfunction, or damage my batteries ?

 

[ducat]

Wouldn't have thought so. The Lummis come with magnets that you have to attach to the battery so it fits the charger.

 

[Rawk]

Hm interesting ! One magnet on the tail, one in the middle would hold the flashlight perfect. Thanks for the quick answer !

 

[DM51]

Magnets have no effect at all on batteries. You can use them for purposes of electrical connection as you suggest.

You should however be careful to ensure there is no possibility of a short occurrring. If you use a magnet to help make a connection inside a flashlight, it is possible if the light receives a jolt or knock that the magnet could become dislodged and make a contact between the battery terminal and the body tube, causing a dead short and sudden rapid discharge of the cell, possibly leading to dangerous over-heating.

 

[recDNA]

Magnets have no effect at all on batteries. You can use them for purposes of electrical connection as you suggest.

You should however be careful to ensure there is no possibility of a short occurrring. If you use a magnet to help make a connection inside a flashlight, it is possible if the light receives a jolt or knock that the magnet could become dislodged and make a contact between the battery terminal and the body tube, causing a dead short and sudden rapid discharge of the cell, possibly leading to dangerous over-heating.

Could I simply put the battery between the cells then surround the connection with electrical tape to prevent the battery from touching the side walls?

 

[DM51]

Could I simply put the battery between the cells then surround the connection with electrical tape to prevent the battery from touching the side walls?

That could work OK, but you'd need to use enough tape to make sure there would be no possibility of a short. And too much tape wound round the end of the cells might make them too thick to fit in the tube.

The best solution would be a solid delrin washer that fits outside the magnet spacer, with the magnet glued inside it. Leef used to make these, but I've just looked on Lighthound and they aren't there any more. Maybe someone else can help here.

 

[Apollo Cree]

Some of the rare earth magnets are fiendishly strong. Under some circumstances, they might be able to mechanically move some of the mechanical components inside the battery. Think of it as being like dropping the battery and mechanically bending things inside the battery. Could they cause something to short out? Cause migration of crystals, etc.? Iron and Nickel are ferromagnetic. Could batteries with nickel or iron in the chemistry have migration problems? Do some of the other battery types have any internal iron components?

In theory, the Hall effect might affect the flow of ions within the electrolyte, concentrating the distribution of current within the cell, but it doesn't seem it would be strong enough to be a big problem.

My gut feel is that there wouldn't be any problem unless you have fiendishly strong rare earth magnets. Maybe not even then.

 

[45/70]

Apollo Cree, I've researched this before, and came to the conclusion, that magnets have no effect whatsoever, on the internal chemistry of battery cells.

You should however be careful to ensure there is no possibility of a short occurrring. If you use a magnet to help make a connection inside a flashlight, it is possible if the light receives a jolt or knock that the magnet could become dislodged and make a contact between the battery terminal and the body tube, causing a dead short and sudden rapid discharge of the cell, possibly leading to dangerous over-heating.

I came up with a solution for this potential problem (from the "old days"). This will only work if there is room enough, but if you take a sheet of paper, or plastic sheet, cut it to the proper cylindrical size, and stuff it in the battery tube, this makes a pretty good insulator to prevent magnets from shorting between the battery cells and the battery tube. This assumes (yeah, I know, uh oh) that the tops of the cells do not have an exposed shell ("-" surface) otherwise, you could run into problems. An added plus, if your cells rattled before, providing your paper or plastic is of the proper thickness, they won't anymore!

Dave

 

[TooManyGizmos]

Agreed 45/70 ..... +1

Magnet spacers between the cells would be OK ... if insulated from housing.