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Do magnets interfere with drivers?

Atomicrox

Atomicrox

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I bought a flat top 18650 batt and it only makes contact inside one of my lasers if I add a small Nd magnet to the + pole.

This laser is case negative, which takes the magnet very close to the driver. Close enough that it gets slightly attracted towards the pill. I'm wondering if this could interfere with the driver because of the inductor.
 





As far as I know, it shouldn't. Magnetic fields are additive, so if there is an additional, ambient magnetic field, it's just like adding a constant to a function and taking the derivative of it. It won't make a difference. Inductors only care about changing magnetic fields and/or changing currents. Since your magnetic is stationary, it shouldn't cause any problems.
 
Bend the spring out to make it longer instead, or at least use a piece of metal. Magnets are not ideal conductors.
 
Have you tried using a blob of solder instead of a magnet?
 
+1 on the soldier blob, I have had some bad experiences with magnets including a magnet shifting and touching the (-) case, shorting out the battery. Scary stuff!
 
^^ thanks man.

I went as far as using a nice sized solder blob, and filing it to a flat button top for a good connection. Works great, no worries about magnet problems. Didnt think about a shifting issue. Another reason for solder. :beer:
 
ryansoh3 said:
+1 on the soldier blob, I have had some bad experiences with magnets including a magnet shifting and touching the (-) case, shorting out the battery. Scary stuff!
Click to expand...

We use a soldered button on our cells.

Button.jpg


It is shorter in overall length . . .

and has lower resistance for better power.

LarryDFW
 
Last edited:
I'll try the solder. Any tips on getting it to stick? Do I heat up the + pole first?
 
Dab some solder on the iron, apply some flux on the + side (optional), touch the + side with the iron for 1.0 second, and feed some solder onto the + side when the iron supplies the heat.
It should all happen very briefly in less than 5 seconds to keep the cell from getting roasted. Good luck! :)
 
If you have any sticking problems just rough up the pole a bit.
 
Wolfman29 said:
As far as I know, it shouldn't. Magnetic fields are additive, so if there is an additional, ambient magnetic field, it's just like adding a constant to a function and taking the derivative of it. It won't make a difference. Inductors only care about changing magnetic fields and/or changing currents. Since your magnetic is stationary, it shouldn't cause any problems.
Click to expand...

I dont understand your calculus analogy! Wait perhaps i do, please correct me if i misunderstand?

So the inductor in the driver is producing some magnetic field, which actually varies. so there is some flux, or the rate of change of the magnetic field density with respect to time.

Adding some constant magnetic field will not effect the overall CHANGE in the magnetic field, as the function of the entire varying field has simply been phase shifted up the y-axis.

So the derivative of this function will not change, since each point in the graph will be shifted up the same amount, therefore, of course, the slope tangents would remain unaffected.

Yes? Thanks! I'm glad im not the only one who likes math.
 
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