Safe 18650 battery alternative?

[mda71]

What worries me was that he tested a AW IMR 1600and shorted it. Within 2-3 minutes the battery reached 220-230 degrees and was unusable after the test.



I going to buy the Protected Panasonic 3100mAh 18650 battery cell - Assembly made by Orbtronic

 

[sailorman]

Looks like the Panny IMR handled a short way better than the AW. both were unusable, but the Panny hit 185. That's about as hot as a cup of McDonalds coffe and, though it would cause a nasty burn, it's not hot enough to ignite most things and unlikely to burn you or destroy the PV in your hand. Meanwhle, the AW hit 235. That's a massive difference. Also worth noting is that neither flamed or exploded. I can live with a battery that only heats up to 185 with no explosion when it's shorted.

As long as the protected 3100 Li-Ions protection circuit works as designed, everything's unicorns and rainbows.
I'd be interested to see the intense heat and explosion that would ensue if that circuit failed.

So, the choice seems to be: Rely on the PCB to prevent a monumental disaster in the event of a short - or - rely on the battery's chemistry to prevent a monumental disaster, even though you'll get a minor disaster.

In some devices, i.e. the Lavatube, you don't have the option of using a protected battery.
Seems like the Panny is the way to go in that application.

I'd be interested in seeing a vid of an overcharging or overdischarge situation. The only real disaster I've had was due to an overcharging condition. Shorts are a lot easier to avoid than an overcharge caused by a malfunctioning charger.

 

[sailorman]

What worries me was that he tested a AW IMR 1600and shorted it. Within 2-3 minutes the battery reached 220-230 degrees and was unusable after the test....

Take home lesson: If you need an IMR, use a Panasonic. If the extra length is not a factor and you feel comfortable relying on the integrity of a PCB, use the Panasonic Li-Ion. Personally, I'll never buy another AW IMR again.

 

[Strontium]

Interesting thing.

ncr18650A 3100mah Panasonic is not IMR, and bare cell without any protection can be shorted for extended period (I think it was 1 hour), and nothing happens. It will still read 3. something volts.

I will try to find that video.

Question , how li-ion Panasonic cell without protection can be safer than IMR ???

at the same time it holds 3 times more capacity.

 

[mda71]

Take home lesson: If you need an IMR, use a Panasonic. If the extra length is not a factor and you feel comfortable relying on the integrity of a PCB, use the Panasonic Li-Ion. Personally, I'll never buy another AW IMR again.

Thanks for your help.

Check out post #20 on page 2. They shorted a Unprotected Panasonic 18650 NCR18650A for 1 hour. Highest temp reached was 133-135 degrees and was still usable.

The reason I want to buy a Protected Panasonic 18650 NCR18650A is that the PCB protects the battery from over charging and over discharging.

I'm still doing some research on this battery but thank you for providing pointing me to the right direction.

Regards,

mda71

 

[Strontium]

Thanks for your help.

Check out post #20 on page 2. They shorted a Unprotected Panasonic 18650 NCR18650A for 1 hour. Highest temp reached was 133-135 degrees and was still usable.

The reason I want to buy a Protected Panasonic 18650 NCR18650A is that the PCB protects the battery from over charging and over discharging.

I'm still doing some research on this battery but thank you for providing pointing me to the right direction.

Regards,

mda71

Sorry guys you are too fast

Yes, that is it

 

[Rocketman]

The short circuit, no burn, no explosion test is for a NEW CELL and is a common requirement placed on many manufacturers that sell cells to U.S. and UK manufacturers (except e-cig manufacturers of course).
The PTC, or current limiting device inside the positive cap will limit current when the cell gets hot.
That's temperature inside the cell, not the outside. The cell will conduct through the short at a high enough current to raise the cell temperature, then slow current to keep the cell from going up in temperature.

One of the problems with a PTC is they don't have the service life of a light switch. After a few actuations, they may or may not work.

Think of the math. How much current is flowing through the shorted wire for a hour?
If it is an average of 2 amps, for an hour, that is 2 amp hours (2000mah), 3 amps for an hour (3000mah), 6 amps for an hour (I don't think so ).

I don't think I would depend on an unprotected cell not to explode/vent with a short.
Even so, an 'almost short' of several amps could heat the cell up just as much, or more.
How would you know if the reason your mod keeps cutting out isn't the PTC, and you have finally worn it out.

 

[sailorman]

The short circuit, no burn, no explosion test is for a NEW CELL and is a common requirement placed on many manufacturers that sell cells to U.S. and UK manufacturers (except e-cig manufacturers of course).
The PTC, or current limiting device inside the positive cap will limit current when the cell gets hot.
That's temperature inside the cell, not the outside. The cell will conduct through the short at a high enough current to raise the cell temperature, then slow current to keep the cell from going up in temperature.

One of the problems with a PTC is they don't have the service life of a light switch. After a few actuations, they may or may not work.

Think of the math. How much current is flowing through the shorted wire for a hour?
If it is an average of 2 amps, for an hour, that is 2 amp hours (2000mah), 3 amps for an hour (3000mah), 6 amps for an hour (I don't think so ).

I don't think I would depend on an unprotected cell not to explode/vent with a short.
Even so, an 'almost short' of several amps could heat the cell up just as much, or more.
How would you know if the reason your mod keeps cutting out isn't the PTC, and you have finally worn it out.

Ahhh.. Yes, the PTC is shown in the exploded diagram on the data sheet. I had assumed that it was a PCB that was just illustrated in a more simplified form. So, there is no real PCB circuit in that Li-ion. That might explain also why the wires got hot enough to melt, yet the battery was lukewarm.

What is the mechanism of the PTC? Is it like a bi-metal switch or something?

 

[Strontium]

Ahhh.. Yes, the PTC is shown in the exploded diagram on the data sheet. I had assumed that it was a PCB that was just illustrated in a more simplified form. So, there is no real PCB circuit in that Li-ion. That might explain also why the wires got hot enough to melt, yet the battery was lukewarm.

What is the mechanism of the PTC? Is it like a bi-metal switch or something?

There is more to it - I found this



https://industrial.panasonic.com/eu/news/nr201005IE002/nr201005IE002/Press_Release_Li-Ion_NNP_E.pdf


"In spite of the increased power, which normally gives rise to an increased safety risk,
Panasonic batteries remain particularly safe thanks to the patented Heat Resistant
Layer (HRL) technology. This solution consists of an insulated metal oxide film
between the electrodes, which prevents overheating even in the case of an internal
short-circuit."

 

[jkmtwo]

I have 2 of these batteries for a flashlight, and they don't work in the Provari, don't know about the Lavatube, but I'm guessing it has something to do with the nipple, its a little recessed as compared to the AWs

 

[sailorman]

Interesting. The Lavatube is made for a shorter battery. It won't even accept anything longer than about 65.2mm.
There is at one Lavatube user who has confirmed that they will work.
The generic batteries that came with my Lavatube measure 65.0mm. These are 0.2mm longer, so they ought to work fine in a LT.
I have yet to confirm that a genuine AW fits in a LT. I suspect it's too long and that's why it fits a Provari while this Panny does not.

 

[Strontium]

Still doing my research on ProVari, and Lavatube.


When it comes to 18650, ProVari is designed to work with the AW IMR 18650 high drain batteries only. (You must use batteries that have a positive nipple on the top. Flat top batteries will not work.)
BIG disadvantage.


Lavatube will work with all flat top 18650 batteries 65mm in length. BIG advantage over ProVari.

ALL Sanyo, Panasonic, Samsung, LG,... 18650 cells are flat top by design. I will be able to "play", and use any of these cells. Plus new cells from these big names are coming, they will be flat top.

 

[micksf]

subscribing

 

[Blakd]

I believe that is why people started using rare earth magnets on the flat top batteries, so they can use them in devices that require a battery with a nipple. I do not know the safety of doing this but have seen it mentioned. I am going to check out these batteries next time I need some more.

 

[Strontium]

I believe that is why people started using rare earth magnets on the flat top batteries, so they can use them in devices that require a battery with a nipple. I do not know the safety of doing this but have seen it mentioned. I am going to check out these batteries next time I need some more.

Yes, that is one way to solve flat top battery compatibility problem. Neodymium magnet (rare earth) have nickel coating, and that is what makes it conductive.

 

[jkmtwo]

I don't know that a magnet would work in the Provari, these batteries fit a little more snug than the AWs

 

[Rocketman]

If a reputable mod manufacturer has designed a mod to accept limited types and models of 18650 cells, who thinks it's a good idea for a user to defeat some of the design (safety?) features?


or, to tell others how to defeat them?

 

[jkmtwo]

I have found that the AWs work in the LT, but not every battery that works in the LT works in the Provari, as someone else has pointed out, its most likely due to the nipple.

When I tried the panny in my Provari there was no wiggle whatsoever, but with the AWs there is the ever so slight wiggle, so the pannys are a more snug fit, and if you actually look you will find this....
View attachment 84596

View attachment 84597

 

[jkmtwo]

The panny is just a bit taller

 

[Strontium]

If a reputable mod manufacturer has designed a mod to accept limited types and models of 18650 cells, who thinks it's a good idea for a user to defeat some of the design (safety?) features?


or, to tell others how to defeat them?

Reputable mod manufacturer has designed something actually very dangerous.
I hope they know that by limiting cell compatibility only to UNPROTECTED bare cells, they are exposing unaware buyers to serious hazard.

Question to all users who might read this: Are you sure that you are using IMR cell, or you just believe whatever your seller tells you?

In their "hunt" for profit sellers often do not check what they are actually selling.

I am writing this after I saw some very bad results from AW (best right?) 18650 IMR cell.

According test results - that is not high drain cell after all. Now we can go to previous question. Are you sure that your cell is safe, because you have to rely on chemistry to protects you- there is not any other protection.

Will always choose brand name like Panasonic, Sanyo, Samsung over re-wrapped cells. Especially when battery seller is hiding what cell is under that PVC wrap.