Magnetic Connection

[Ben]

Hi everyone,

I was thinking about small battery packs for bike lights today and I was wondering whether it would be possible to use rare earth magnets as a solderless battery connector.

Most neodymium magnets have a nickel coating on them to contain the magnetic powder. Most battery tabs I see are made out of nickel also, so it seems feasible.

Do you think it is possible to solder to the nickel casing of the magnets without demagnetising them?

Would the nickel have a low enough resistance to prevent thermal demagnetising under high current draw?

 

[Link]

You'd hit the curie point on most magnets, methinks. But otherwise should work okay...

But what "magnetic powder"? NdFB magnets are solid, but very brittle. They would break in a second if they didn't have the nickel coating.

But I don't think I'm seeing the picture here (sorry, it's really late). What's the advantage to using magnets?

 

[fechter]

Interesting idea. The heat from soldering will demagnetize the magnets, so that's out. You could possibly fold a tab on the end of a battery over a magnet glued to the end. This way the power does not go through the magnet and you don't need to solder anything. The magnet polarity would prevent you from connecting cells backward :wink:

You might lose connection if you hit a bump. Pressed connections will be prone to corrosion over time. It works better if the clamping force is much higher, like you get with a bolted ring terminal.

 

[Doctorbass]

I use that since 1 yyesrs for testing each cell with my RC tester.

That save me alot of time!! at 5A, a simple 1cm x 1cm x 0.4cm magnet is perfect.. no heat loss!
I soldered directl;y the wire on them.. the magnetic field did'nt change too much...


Doc

 

[Ben]

But what "magnetic powder"? NdFB magnets are solid, but very brittle. They would break in a second if they didn't have the nickel coating.

Maybe that's what I'm thinking of (I broke one and started pulling powder off the break).

The sandwich method sounds good and with a decent magnet, it should be pretty strong.

I'm not sure about soldering now, but I'll give it a test if I can find my hard drive magnets.

For a large pack I can see it getting expensive.