Magnets

Batteries and Chargers Chargers
1

Anybody got a source for magnets for charging that would take a wire soldered to it?

2

In my experience, neodymium magnets don't do well w/ heat (I've totally ruined a bunch of them). You could probably solder to a larger one but the tiny ones probably won't have much magnetism left afterwards. I'd use a little bit of conductive adhesive, and cover that w/ a drop of epoxy.

I've spent over $100 on magnets at DX, but I stopped buying them when they raised prices and reviews started to note the totally wrong size getting shipped.

If you just need a couple, radioshack has them, otherwise https://www.google.com/search?q=neodymium+magnets

3

Samarium cobalt (Sm-Co) has a much higher Curie temperature, ~700 C than neodymium, 310-400 C.

It should also conduct electricity well.

http://en.wikipedia.org/wiki/Samarium%E2%80%93cobalt_magnet

4

http://www.dealextreme.com/p/super-strong-rare-earth-re-magnets-8mm-20-pack-4248

5

btw, they probably won't send you the wrong size if you order small ones, only if you order big ones ;)

and you could also just solder a small steel washer to your wire to stick the magnet to

6

i saw a ad in blf from someone who was selling charger adapters with wires soldered to magnets but i can't find it now. have u seen it?

7

Maybe this: http://www.mindsetsonline.co.uk/product_info.php?cPath=18_635_519&products_id=119

8

Are you after wired adapters for use in a cradle charger, so that you can use a cradle charger to charge a cell larger than the cradle will accept? Or are you after magnets attached to a cable with banana plugs, for use with hobby charger?

Either way, this guy can help you out: -

http://www.cpfmarketplace.com/mp/showthread.php?244152-charging-adapters-to-fit-ANY-SIZE-li-ion-into-an-18650-charger-(Pila-IBC-or-other)

http://www.cpfmarketplace.com/mp/showthread.php?244152-charging-adapters-to-fit-ANY-SIZE-li-ion-into-an-18650-charger-(Pila-IBC-or-other)&p=2736994&viewfull=1#post2736994

9

If you have a harborfreight near they sell neodymium in 10 packs about 8mm I believe for $1.50

10

I just ordered some from here.

http://www.magnet4less.com/index.php?cPath=11

11

Why solder?

Lennart

12

hadn't thought bout that

13

Nicely done Lennart.

14

My setup is similar to Lennart's, except I plasti-dipped everything metal but the head of the nut where the magnet sticks.

Is anyone aware of an electrically-conductive glue or epoxy? I would like to permanently affix some small magnets to the King Kong 26650s without adding too much resistance. I have done so with 18650s and shrink tubing in the past, but I don't have the right size for the larger cells.

15

there is elec conductive epoxy

i would guess that any electronics store would have it

16

I placed an order with magnet4less a few days ago to try out a few different ideas . The only thing with Lennart's solution (which is perfectly fine) is that it can increase the resistance. For charging leads its fine, but if you want to use them for test leads for your DMM, the less number of connections the better.

I'm going to try those Samarium ones, but my original idea is to use this magnet with a countersunk hole and a matching (well, probably bigger) brass bolt which the wire would be soldered to.

17

yes, I've searched for that quite a bit. radioshack has 'circuit writer', and it is perfect for doing that. It comes in a pen shaped applicator, there is a spring loaded plunger in the tip. Although handy, the tip will eventually clog, but can be disassembled and cleaned, or you can just open it and apply it w/ a toothpick after that happens. I apply a very thin layer between magnet and anode, then a couple thin layers (dry in between) around the edge.

18

Thanks for the heads-up. I have a CW pen, and I'll try that.

FWIW, if you store the pen tip-down after the first use, it takes longer before you need to refurb the tip.

19

i learned that the hard way. I haven't found a suitable solvent for the one that was around so long it all dried up - I can dissolve it but it doesn't stick again...