Magments for short 18650?

I had made an order from Fast Tech, and got the normal great service, and received it today, 15 days after the order. I am very pleased to receive so fast.

As part of the order I ordered 2 Sanyo UR18650 unprotected batteries. Upon arrival I noticed that there was not button on the top, and they were too short to work in my lights. I remembered that I had received some batteries and after opening I found a very small round item on the floor. I assumed it was a magnet. So I placed the magnet on the end of the battery and it worked.

So since I have only one magnet, where do I get more or is there another/better fix?

Deal Extreme(DX) has lots of small magnets.

Or a permanent pix would be to solder some lead onto the tops, as I’m afraid the magnets will shift and cause a short.

This is my magnet source in the US.

I would think that if the magnets are smaller than the entire base including the wrapping the magnet could not slip because on the wrapping so as to short, but I admit I have no experience.
Would not the soldering get the battery hot?

I think FT has some magnets that will work, and I intend to visit Harbor Freight.


I’ve only experienced non-contact with my unprotected Samsung 18650’s, so I’m sure there are a variety of cell tops.

It takes only five seconds or so to solder, so I don’t think it would harm the battery too much. :slight_smile:

I have done it several times with laptop pulls that don’t have a button top. Never seen any problems.
I do use a 150watt soldering gun and a wet towel wrapped around the battery to keep it cool with a good amount of flux. Soldering it as fast as possible.

Thanks 007. Sounds reasonable to me.

A drop or two of superglue around the perimeter of the magnet works for me.
I got the magnets from FastTech.

Yup, superglue sounds great!

I have some from DX and some from banggood. DX is just too slow, BG was quite fast (~14 weeks) and cheaper. Magnets work very well and don´t move.

What lights? On my S2 the tail spring was compressed by the isolator for the tailcap that held the plunger in place so I just took it off. Added a few mm’s to the spring length and made it functional again; if you’ve got an isolator on the tail cap it may be worth trying it without to see if it makes a difference. I also soldered the plunger on it for additional length but it worked without it.

Generally undesired contact on the tailcap isn’t a huge issue since it just results in accidental activation, not a “dead short” that would cause immediate cell damage. Force should be identical on cells so while it may be more of a hassle w/lager ones, it shouldn’t be more force per say.

The lights I tried were UF 501b, and Convoy S2.

I got some magnets from Harbor Freight, but they were pretty thick, and would not work, and the 501b now will not work with any battery. I must have put too much force on the tail cap when I screwed it on. :frowning:

Although the battery with the thick magnet would not work in the S2 the light works as normal with my other batteries. Guess I messed the 501b.