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Thread: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

  1. #1

    Default Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Where do I find reasonably priced magnetic spacers to convert 18650 flat tops to button tops?

    I looked on fleabay but I don't want to pay $1 per spacer. I mean, I can afford it but the cost seems excessive and I despise rewarding greed in any shape or form.

    I don't eat $12 hamburgers or drink $15 cocktails. I quit rewarding greed after greedy mortgage brokers crippled our economy.

    (Okay, let me just climb down off this soap box).

    Thank you.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    One of the reasons you don't find an abundance of these, is that they're generally discouraged, and I don't think many serious vendors would offer them. Keep in mind that you don't need contact between the top and bottom of a battery to make a (dangerous) short, but the top and any other metal part of the battery will do. A paperclip slid in at the top could easily get the job done.
    To make matters far worse though, the shell of a flashlight is often connected to the bottom of the battery. Any contact between the top and the shell, would then cause a short.
    Then there's the risk of physical damage, such as breaking free a spring, which in turn could short out things, and so on.

    Speaking of generally discouraged, I'd like to discourage it as well, but you probably already noticed that. :-P

    There are good high-quality button tops out there (for a good price), both protected and unprotected.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by terjee View Post
    One of the reasons you don't find an abundance of these, is that they're generally discouraged, and I don't think many serious vendors would offer them. Keep in mind that you don't need contact between the top and bottom of a battery to make a (dangerous) short, but the top and any other metal part of the battery will do. A paperclip slid in at the top could easily get the job done.
    To make matters far worse though, the shell of a flashlight is often connected to the bottom of the battery. Any contact between the top and the shell, would then cause a short.
    Then there's the risk of physical damage, such as breaking free a spring, which in turn could short out things, and so on.

    Speaking of generally discouraged, I'd like to discourage it as well, but you probably already noticed that. :-P

    There are good high-quality button tops out there (for a good price), both protected and unprotected.
    I could not have said it better.

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  4. #4

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by terjee View Post
    One of the reasons you don't find an abundance of these, is that they're generally discouraged, and I don't think many serious vendors would offer them. Keep in mind that you don't need contact between the top and bottom of a battery to make a (dangerous) short, but the top and any other metal part of the battery will do. A paperclip slid in at the top could easily get the job done.
    To make matters far worse though, the shell of a flashlight is often connected to the bottom of the battery. Any contact between the top and the shell, would then cause a short.
    Then there's the risk of physical damage, such as breaking free a spring, which in turn could short out things, and so on.

    Speaking of generally discouraged, I'd like to discourage it as well, but you probably already noticed that. :-P

    There are good high-quality button tops out there (for a good price), both protected and unprotected.
    So I should just toss the flat tops? Why do they make them to begin with?

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by mickeyfinn View Post
    So I should just toss the flat tops? Why do they make them to begin with?
    In a way, flat tops are the originals. These batteries are really industry batteries, used in power tools, laptops, electrics cars and the like. Button top is more of an add-on, with some lights using it for reverse polarity protection.

    If they're of good quality, I'd hang on to them for any future use. Just like some lights require button tops, others require flat tops. Some accept both. Even if they don't fit your current light, they might fit another light in the future.

    Also, with Nitecore F1, you could use them as a power bank if you'd like. It's a really neat little thing, that'll let you use USB to charge 18650s, and also use 18650s to charge USB-devices. Cheap too, around $8 or so I think. If you want to use them in a light, there's Convoy S2+ for example, which is a decent light that can be found in a lot of different configurations, often around $10. Makes a nice backup light.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    In most cases, flat tops are unprotected cells, while button tops are protected. The advantage of protected cells is the printed circuit board (PCB). Conversely, the disadvantage of protected cells is also the printed circuit board. In other words, the PCB prevents over charging and over-discharging, making the use of protected cells essentially fool proof. On the other hand, the PCB becomes another potential source of electronic failure. Unprotected cells won't fail suddenly leaving you in the dark, but they require a thoughtful user who can monitor voltage and manually avoid over discharging. Most flashaholics stock both varieties for different applications.

    My advice is to keep your flat top cells, but not to use magnets or spacers to convert them to button tops. The danger of a short circuit is real. Good cells of both varieties are inexpensive enough that it should not be an issue.
    Last edited by Modernflame; 08-11-2017 at 06:23 PM.
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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Hi terjee,
    I have some 18500's I use in my Surefire 9P, G3 & my Seraph-9. Because they are flat tops, I use a tiny neodymium magnet, surrounded by three "gaskets" from IMR, and then where the positive end of the bottom and negative end of the top Cell are connected by the magnet I wrap a layer of electrical tape around it(thus keeping the magnet from physically shorting out against the body). What is your opinion of their safety?
    I have been using the setup for a couple of years without any problem.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by Crazyeddiethefirst View Post
    I have some 18500's I use in my Surefire 9P, G3 & my Seraph-9. Because they are flat tops, I use a tiny neodymium magnet, surrounded by three "gaskets" from IMR, and then where the positive end of the bottom and negative end of the top Cell are connected by the magnet I wrap a layer of electrical tape around it(thus keeping the magnet from physically shorting out against the body). What is your opinion of their safety?
    It's hard to comment based on the description alone, without having seen it. It sounds like it's not ideal, but far from horrible as well.

    It really depends on how reliable it is, how fast/easily it can fail, and what can go wrong when it does fail (running on the assumption that anything and everything fails eventually). I have to admit it sounds like an upgrade from just sticking a magnet on top, but personally I'd be wondering about things like the tape failing if the light is accidentally left in the sun (heating the glue of the tape) and so on.

    One of the things I can't really see, is whether the magnet is small enough that it could get in and short out the battery, or large enough that it could connect the battery to the chassis, if the arrangement starts to fail.

    It's probably not something I'd do myself, but I tend to be a bit on the cautious side with LiIons. It does sound better than some other solutions I've seen.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    I agree with @terjee, but like @Crazyeddiethefirst, I wound up with some flat tops I could not use due to a shipping error. Those of you who frequent the other forum know what went on about a year ago. I found some rare earth round magnets that were designed to do just this thing, on either Banggood or Gearbest. I also bought some of the gaskets Crazyeddie is talking about from IMRBatteries. They look a lot like the reinforcement rings we used to use for notebook paper in ring binders, but thicker, and the hole is smaller. They are at least twice as thick as the reinforcement rings. I used a single gasket on each cell, but I suppose you could stack two if you wanted. I tested the magnet after I got it set up. I whacked it as hard as I could against the heel of my hand, and nothing moved. I suppose if one wanted to be really sure a drop of two of Elmer's on top of the gasket around the magnet would help hold things in place. By putting it there, it should not wick underneath the magnet and cut down on connectivity.
    You don't NEED a parachute to skydive. You DO need a parachute to skydive twice.

  10. #10

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    I always use 100 watt soldering Iron to convert cells in to buttontops it works great

  11. #11

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Fastest method - Drop of solder using 100W soldering iron. Second - small piece of copper soldered with 100W soldering iron. Third - copper wire bent like spiral soldered with 100W soldering iron.
    Last edited by fonfan; 08-12-2017 at 02:14 PM.

  12. #12

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by fonfan View Post
    Fastest method - Drop of solder using 100W soldering iron. Second - small piece of copper soldered with 100W soldering iron. Third - copper wire bent like spiral soldered with 100W soldering iron.
    Why 100W soldering iron?

    Why not 80W, 70W or 60W soldering iron?

  13. #13

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Most of the people think that Heating up a Cell is very Dangerous So if you take soldering Iron of 80 or 100 watt You put in a lot of heat but you will do this In A Very short Time Five or six Seconds
    this Short amount of time is Enough to apply the tin
    After the soldering cool the cell on a wett sponge

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by mickeyfinn View Post
    Why 100W soldering iron?

    Why not 80W, 70W or 60W soldering iron?
    Iíll try and explain.
    Normally the area you need to heat when soldering electronics is much smaller than the top of an 18650 battery. That large area is a heat sink. It will pull the heat out of the iron much faster than a small area. A higher wattage iron will lose heat at a slower rate and also it will recover from the heat loss much faster. It will give you a much better chance of satisfactory results. Based on your question I am assuming your soldering experience is somewhat limited. I strongly suggest that you practice first on an aluminum can or similar then work your way up to a battery. Soldering is a good skill but itís not something you were born knowing how to do, it takes practice.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    It is possibly to solder the tops on, but I wouldn't recommend it for anyone that isn't a professional or experienced amateur. It's back to the whole "yeah, it's possible, but also dangerous"-side of things.
    To do it somewhat safely, you'd need to inspect the soldering to make sure it's properly bonded, you'd need to make sure it won't be too soft, won't chip, and so on.

    And you'd need a good feel for temperature movement, to heat the solder and pad high enough to bond, without heating the battery itself too much. That's why you'd need 100W.

    I'd actually rate the using of well protected magnets as mentioned, as less dangerous, for anyone not experienced.

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    Flashaholic* Crazyeddiethefirst's Avatar
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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by terjee View Post
    It's hard to comment based on the description alone, without having seen it. It sounds like it's not ideal, but far from horrible as well.

    It really depends on how reliable it is, how fast/easily it can fail, and what can go wrong when it does fail (running on the assumption that anything and everything fails eventually). I have to admit it sounds like an upgrade from just sticking a magnet on top, but personally I'd be wondering about things like the tape failing if the light is accidentally left in the sun (heating the glue of the tape) and so on.

    One of the things I can't really see, is whether the magnet is small enough that it could get in and short out the battery, or large enough that it could connect the battery to the chassis, if the arrangement starts to fail.

    It's probably not something I'd do myself, but I tend to be a bit on the cautious side with LiIons. It does sound better than some other solutions I've seen.
    Thanks for your opinion. I am using incredibly small but powerful neodymium magnets that are not large enough to touch the flat top cap and the body at the same time. The electrical tape and IMR Washers(I use two so the amount of any movement is limited) are merely additional safeguards. I should point out that any of the new 18500 cells I buy will be buttontop. After reading this thread, as well as an unfortunate experience very recently(see my thread "Dealing with Lithium-ion batteries while impaired"), I have opted to no longer use my 4 18500 flat tops in tandem. They will now be relegated to my Jetbeams with an adapter(similar to the Sunwayman V11r), that can use the flat top 18500's. Once they have reached their end of usefulness they will be recycled and only replaced with button top only. Thanks to all who contributed to this thread, both asking questions and giving answers. Raising awareness of the potential to cause a short when using Lithium-ion batteries can only be beneficial when shared. I had come to believe using magnets was an acceptable practice, and even though I took precautions, I feel it best for me personally to stop doing so. Balancing the cost of a short, possible burns, starting a fire, hazardous gas release, etc. Vs $10 for a couple new cells, it is an easy choice for me. I realize others may make a different choice, but having heard from various voices of experience on the forum, the choice is easy! Thanks CPF!

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by Crazyeddiethefirst View Post
    .... I am using incredibly small but powerful neodymium magnets that are not large enough to touch the flat top cap and the body at the same time....
    The magnet doesn't even necessarily have to reach the side if the tube to cause a short, since (for most common cells) the can itself is usually negative too (!) ...

    Quote Originally Posted by Crazyeddiethefirst View Post
    Thanks to all who contributed to this thread, both asking questions and giving answers. Raising awareness of the potential to cause a short when using Lithium-ion batteries can only be beneficial when shared. I had come to believe using magnets was an acceptable practice, and even though I took precautions, I feel it best for me personally to stop doing so....
    I, too, no longer use magnets
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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?



    easy. just buy a spot welder. get nipples from fasttech aliexpress etc


  19. #19

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Who here has used a magnet to convert an 18650 flat top and actually suffered a short or encountered some other problem?

    Is it safer to use a magnet this way in an anodized flashlight?
    Last edited by mickeyfinn; 08-16-2017 at 01:11 AM.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by mickeyfinn View Post
    Who here has used a magnet to convert an 18650 flat top and actually suffered a short or encountered some other problem?

    Is it safe to use a magnet this way in an anodized flashlight?
    Things can happen. I don't use magnets, or solder. Cells are cheap and many quality vendors sell great cells with button tops for not a lot of money, so it's prudent to just go that route unless you're down to your last pennies and just have to forego paying the electric bill, or mortgage, in order to jerry-rig your flat tops, that just don't work in a particular light.

    With lithium ion cells, which pack a lot of energy in a sealed aluminum tube, you probably just want to err on the side of caution, but many people successfully use magnets.

    Chris
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  21. #21

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    The question was:

    "Who here has used a magnet to convert an 18650 flat top and actually suffered a short or encountered some other problem?"

    Let's ask it another way.

    Who here HAS USED MAGNETS to convert 18650 flat tops and had no problems doing it?

    I think a lot of folks here have used magnets in the past to convert 18650 flat tops but don't want to go against the "cautious flow" the thread has taken.

    I have used different types of magnets for years in different configurations in different lights and experienced nary a problem.


    Last edited by mickeyfinn; 08-16-2017 at 01:51 AM.

  22. #22

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    I used and had no problem. But it's very unsafe and I don't recommend use magnets with LiIon acc.

  23. #23

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Earlier I had same problem with Nitecore P36. The P36 battery holder is too small for protected cells (some cells working, but very hard to fit), and not supported flat top cells... but I didn't want to use magnets. I ordered two pcs LG INR18650MJ1 3500mAh cell "button top" version and this solution was perfect for me.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by mickeyfinn View Post
    The question was:

    "Who here has used a magnet to convert an 18650 flat top and actually suffered a short or encountered some other problem?"
    ....
    I didn't search for long, but found this thread easily ...

    http://www.candlepowerforums.com/vb/...d-short-danger!

    ... with several posters describing a variety of shorts, close calls, and near misses
    ... is the archimedes peak

  25. #25

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by archimedes View Post
    I didn't search for long, but found this thread easily ...

    http://www.candlepowerforums.com/vb/...d-short-danger!

    ... with several posters describing a variety of shorts, close calls, and near misses
    This is pretty funny. I started the thread asking where to buy magnets and look what developed from that simple query.

    As far as the referred post, I did see it. But it was 11 years old. Have Li-ons changed in 11 years? I would guess so.

    And yup, it's full of "close calls and near misses," like car accidents that never happened.

    But I must have missed those shorts, unless you count shorts caused by foolish use of magnets.
    Last edited by mickeyfinn; 08-16-2017 at 03:49 PM.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by mickeyfinn View Post
    This is pretty funny. I started the thread asking where to buy magnets and look what developed from that simple query.
    ....
    Forum members here may just be trying to help you (and others) stay safe ....

    Quote Originally Posted by Crazyeddiethefirst View Post
    .... Balancing the cost of a short, possible burns, starting a fire, hazardous gas release, etc. Vs $10 for a couple new cells, it is an easy choice for me ....
    Sounds like you are aware of the issues, though mickey
    Last edited by archimedes; 08-16-2017 at 04:19 PM.
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    Flashaholic* ChrisGarrett's Avatar
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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by mickeyfinn View Post
    This is pretty funny. I started the thread asking where to buy magnets and look what developed from that simple query.

    As far as the referred post, I did see it. But it was 11 years old. Have Li-ons changed in 11 years? I would guess so.

    And yup, it's full of "close calls and near misses," like car accidents that never happened.

    But I must have missed those shorts, unless you count shorts caused by foolish use of magnets.

    https://www.ebay.com/sch/i.html?_fro...p2045573.m1684

    You can Google other places.

    Chris
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  28. #28

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Safety and number of people having experienced something, just doesn't work like that.

    How many people here have had an accident, while drunk-driving, while wearing nothing but red socks?
    Few or none? Must be safe then.

    It's the same thing really. People deem it not safes for don't do it, so the numbers are low, but that doesn't make it safe.

    It's really hard to pin a number or other meaningful measurement on it though. So many different people, lights, batteries, and even magnets. A lot of them are brittle, so even a magnet too large to short the battery could break off a piece, and then short anyway.

    Nothing I wrote in this thread was intended as offensive, trolling, putting the OP down for asking (it's good he did), but rather caring enough to comment. I suspect that applies to the majority here, quite possibly everyone.

    Oh, and as to changes over time affecting safety, there's definitively been changes, but it goes both ways. There are also more powerful batteries available now, which can be a higher risk.

  29. #29

    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by terjee View Post

    How many people here have had an accident, while drunk-driving, while wearing nothing but red socks?
    Few or none? Must be safe then.
    I appreciate your other comments and cautions concerning this topic.

    But your above statement concerning driving is not only illogical but completely fallacious.

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    Default Re: Where to buy reasonably priced magnetic spacers to convert 18650 flat tops?

    Quote Originally Posted by mickeyfinn View Post
    I appreciate your other comments and cautions concerning this topic.

    But your above statement concerning driving is not only illogical but completely fallacious.
    It was just intended as a pass at humorously illustrating how few failure events doesn't always imply safety, such as if people are simply not doing it, out of either precisely safety concerns, or merely random reasons.

    One can't take "it's safe" from lack of bad experiences doing something, if it's not done often enough.

    Also, it was just intended as a generic remark, not aimed at anyone, or ment to imply that anyone suggested it. Sorry if it came across the wrong way, not my intention. CPF is a lovely and civilized place, and I always try not to change that.

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