A New Way To Deal With Flat Top Li-ion Batteries !

[lasersbee]

Still waiting on that response from panasonic li-ion battery tech.......

Don't hold your breath...
I don't have time to waste on your childish requests.

Did you even read the quick search link I found in 5
seconds ?? Of course not.... because you are always
right....

Jerry

 

[Accutronitis]

Don't sweat it, I sent them an email for you......

Thank you for your inquiry.

Your inquiry has been successfully accepted.
Acceptance date/time: February 19, 2017 - 22:12 (Japan Standard Time)
Our staff in charge will contact you shortly.

Your inquiry No. is 118720.
You can confirm the contents of your inquiry by entering your e-mail address
and customer confirmation key from the following URL.

 

[lasersbee]

Don't sweat it, I sent them an email for you......

For me.... :thinking:
I highly doubt that.....

I see you tend to ignore facts that are laid at your
feet just to prove that YOU are right... So sad..:cryyy:

Here's another link at your feet...
https://en.wikipedia.org/wiki/Neodymium_magnet


Jerry

 

[BowtieGuy]

Hey Jerry, great reference to the K&J Magnetics site "https://www.kjmagnetics.com/specs.asp", they have one of the widest selections of neodymium magnets around, if you're looking for a particular size magnet, they've probably got it! :yh:

 

[lasersbee]

Hey Jerry, great reference to the K&J Magnetics site "https://www.kjmagnetics.com/specs.asp", they have one of the widest selections of neodymium magnets around, if you're looking for a particular size magnet, they've probably got it! :yh:

Yeah...and they show the Electrical Resistance of their
Neodymium Magnets just like the other Link to Wiki.

I'd believe those two references way before a guy that
uses Clay and Soapy Water to clean Laser Optical Lenses.:beer:

Jerry

 

[Cyparagon]

I myself will not be using magnets......

I won't either. My problem remains that you've claimed magnets will not last passing a modest current. THAT IS DEMONSTRABLY FALSE.

I'll tell you what smart guy you send panasonic li-ion battery tech a email stating your going to use a neo mag as a conductor between two of their 18650 Li-ion batteries and if they say Hey that's a great idea i'll shut the #%@$ up !

You're shifting the burden of proof, backpedaling, and moving the goalposts.

My problem remains that you've claimed magnets will not last passing a modest current. THAT IS DEMONSTRABLY FALSE regardless of what some guy at Panasonic says.

your making an assumption....

You've missed English class too many times. When you give a declarative statement ("Marty has six apples", "this is the best method", or "this will not last under current"), it is EXPECTED to be received as fact BY DEFAULT.

Do not blame your failure to qualify your statements with "in my opinion" or "in my experience" on everyone else. It is YOUR failure to communicate using an agreed upon language. Take some goddamn responsibility. This is laughable.

 

[Photonjunky]

If I might take a moment to grab the wheel and steer this conversation in a more productive direction...
Never seemed to me to be a good idea to apply soldering temperatures, however briefly, to something as temperamental as a Li-Ion battery. Yes, I have tried the rare-earth magnets, and they do seem to work well, for the lower-current (say, 1 to 2.5A) green and red diodes (it's worth pointing out that the current is actually carried by the nickel plating, NOT the magnetic core, so the resistance of the NdBFe core is irrelevant). But, that said, for the high current "Big Blues" (3 to 6 A), the small cross-sectional area of the plating becomes problematic, and a lower-resistance solution is preferred; I believe I have found one.
Ebay item number 301981433789...9.5mm diameter X .5mm thick flat copper discs (seller has numerous other diameters and thicknesses). Bonded to the battery end with conductive silver epoxy, my Fluke 77 ohmmeter sees less than .1 ohm increase in the cap resistance. So, there you have a low-resistance extension, with no heat applied, excellent thermal conductivity, and no centering spacers needed. Would seem to solve all problems, AND, create no new ones...
(or, am I missing something?).

 

[Alaskan]

I like it, the magnets have been a concern of mine. An O ring could keep them from shorting to the side of the host, if dropped and moving etc., and appears to work well enough, but this epoxy method seems like the safest way to go for lower currents, but high current, can the material degrade? Also, .1 ohms at 10 amps is a 1 volt drop, and at ten amps that is 10 watts of heat being produced by it. I used a very extreme example, I don't know of a laser pointer which draws 10 amps, but I bet there are some custom jobs with combined or knife edged diodes which do. Although fve amps of draw isn't so unusual today, that is 2.5 watts of heat and wasted power from a .1 ohm junction. That said, what is the voltage drop from a thin nickel plating?

Something to consider. However, if the .1 ohm you measured was from something else, like the lead resistance of your ohm meter, then none of what I wrote applies. Would be better if you could place the leads across the copper piece and the battery top and measure the voltage drop at a known current being drawn, then you would know what is going on.

 

[Alien Laser]

Cyparagon

the gif is hilarious lol :crackup:

 

[RedCowboy]

I like the solder top method better than magnets that can get knocked against the housing if dropped or banged around, I have put O-Rings around my round neo magnets before but I still don't like loose stuff in my circuit, not when I run 3 cells and if 2 short to case I would have a live 6 watt laser.

I have to say this is much better than magnets in my humble opinion, but if you use magnets insulate the edges, tape, hot glue, something.

p.s. We really should all be running dual switches on our lasers for safety, I have on a few but usually don't, but it's a good idea for added safety.
Loose magnets between cells has always felt wrong. Just my opinion. :beer:

@ Alaskan, yes it's the skin of the neo magnet that carries the load, not ideal at all as the thickness varies, a 4.5a SXD draws 3 amps at 8 volts. 24w in 22w out and the 44 diode makes 15w of heat and 7w of light.

 

[Accutronitis]

If I might take a moment to grab the wheel and steer this conversation in a more productive direction...
Never seemed to me to be a good idea to apply soldering temperatures, however briefly, to something as temperamental as a Li-Ion battery. Yes, I have tried the rare-earth magnets, and they do seem to work well, for the lower-current (say, 1 to 2.5A) green and red diodes (it's worth pointing out that the current is actually carried by the nickel plating, NOT the magnetic core, so the resistance of the NdBFe core is irrelevant). But, that said, for the high current "Big Blues" (3 to 6 A), the small cross-sectional area of the plating becomes problematic, and a lower-resistance solution is preferred

That's what I said, The plating carries the current, not the magnet because the magnet won't.......

 

[diachi]

That's what I said, The plating carries the current, not the magnet because the magnet won't.......

Why'd you talk about the really high resistance of the magnetic core then...?

 

[Accutronitis]

Why'd you talk about the really high resistance of the magnetic core then...?

To point out the magnetic core does not carry any of the current and only the plating does with some magnets having thicker plating than others but it's the plating that has to do all the work for good or bad......

 

[lasersbee]

That's what I said, The plating carries the current, not the magnet because the magnet won't.......

Hmmmm..............

There is one more thing that no one here seem to be aware of which is a little known fact and word of warning for anyone that uses a neodymium magnet as a conductor of electrical current between two Li-ion batteries, Neodymium magnets should never be used as a conductor of electrical current because the electrical resistivity of the magnetic materials used is relatively high, The conductivity is about 1/50th that of copper which makes it a very poor conductor of electricity !

"Neodymium Iron Boron" (NIB) rare earth "super magnets" may be very strong, and very cheap and they're all over eBay BUT they, themselves, conduct electricity very poorly. Much like the even cheaper black ferrite magnets, the black ceramic that NIB magnets are made from has resistance up in the hundreds of kiloohms ! Not something you should ever have between your high current, high discharge Li-ion cells and in turn used in a high drain device such as a 1 watt and higher laser, I would also advise against using them in even lower powered lasers as well, The potential for a cascading thermal runaway that can be caused by the resistant properties of neodymium magnets when used as a conductor of electrical current between two Li-ion batteries is high and even if that has never happened to you (due to the relatively short run times of hand held lasers) there is still the possibility of damage to other electrical components used in a handheld laser due to the very poor electrical connection and resistant properties of a neodymium magnet used between two Li-ion batteries which could lead to wild voltage spikes and swings in the laser driver circuit.

Hmmmm... either it's a lapse of memory or just Selective memory...:undecided:

Jerry

 

[Accutronitis]

Hmmmm..............



Hmmmm... either it's a lapse of memory or just Selective memory...:undecided:

Jerry

I'll say, Or worse just disregarding posts and quoting others is called cherry picking and is poor form.....

Just one other thing, If you are connecting to the out side of a neodymium magnet to test for resistant you are more than likely going to get a false reading due to the extremely thin metal flashing that is used to "seal" the magnetic material inside, That's why you won't see resistance up in the hundreds of kiloohms BUT if you are relying on that extremely thin metal flashing that is giving you halfway good resistance reading to carry real higher current it won't for long, If you completely stripped off that very thin metal flashing and tested it again you would see the resistance up in the hundreds of kiloohms, But if you want to use that mag later don't strip the flashing off because the mag will begin to deteriorate slowly.......

I'm willing to bet if you took a neo mag that you have been using for a while and looked at it's contact surface under a microscope you would prob see many little arks through that thin metal flashing.........

in other words plating.....

I went on to say.....

How much amperage do you think that very thin flashing of metal on the surface of a magnet can it support ?

Remember we are talking about anywhere from 1 amp up to 5 amps +......

but for what ever reason you just disregarded those posts, but anyways :horse:

This is my way, You do it once and never think about it again and you don't have to mess with O-rings or magnets or epoxied copper washers, batteries are unaffected IF DONE CORRECTLY, great electrical connection, use it, don't use it, it up to each person to decide.........




But if you insist on using magnets don't use cheap ones because the cheaper the magnet the thinner the plating, high quality magnets sometimes use a copper plating followed by a nickel plating......

lasersbee you can neg rep me till the cows come home because unlike 99.9% of the members here I could care less about your opinion, You keep saying I always have to be right but I've said at least a handful of times I was wrong, So much for your theory, The truth of the matter is it not me trying to be right BUT you trying to find fault in everything I say, I've never before seen a company representative that acts as hostile as you do, Do you own "laserbee" or just work there ?