Are AW's IMRs really LiMn?

[Jay T]

From everything I have read AW's new IMRs are supposed to be Lithium Manganese, the same as the Emoli cells. Looking at LuxLuthor's LiIon guide some things just don't add up.

http://www.candlepowerforums.com/vb/showthread.php?t=203788

According to the guide only Emoli uses this formula.

There is another formula called Lithium Nickel Cobalt Manganese, sounds almost the same. The easiest difference to see is that these max out at 4.1V vs 4.2V.

Could this be why several of us have noticed that these cells will drop back down to 4.1V while sitting on the table?

Could charging to 4.2 be slightly overcharging?

Anybody with some true Emoli Lithium Manganese cells ever notice their cells relaxing the way these cells do?

 

[Benson]

From everything I have read AW's new IMRs are supposed to be Lithium Manganese, the same as the Emoli cells. Looking at LuxLuthor's LiIon guide some things just don't add up.

http://www.candlepowerforums.com/vb/showthread.php?t=203788

According to the guide only Emoli uses this formula.

That guide was posted in February 2008. AW's first IMR sales thread was started in October 2008. It seems quite probable that Emoli was the only source at the time that was written, but I don't see how that casts doubt on AW's cells.

There is another formula called Lithium Nickel Cobalt Manganese, sounds almost the same. The easiest difference to see is that these max out at 4.1V vs 4.2V.

So you suggest that AW is not only lying about the chemistry (for no evident gain, but I guess no real harm to him), but also giving us bad charging data that will halve the cycle life, and make him look bad when his cells don't last? :thinking: I guess I just don't see the motivation for that... :thinking:

Anybody with some true Emoli Lithium Manganese cells ever notice their cells relaxing the way these cells do?

I can't say I have, but I just grabbed an IMR26700 that had been sitting for a couple weeks, and it measures 4.05V -- but I'm not certain it was charged to 4.2V (one of my chargers I use on these stops at 4.15V), and I think it had a few seconds of use on it, just checking to see if two of them would a Mag61 right off the charger (they didn't, but I don't have enough AW C-cell extenders to use them in my 2C Mag).

 

[LuxLuthor]

Benson, if you read my first post thread that Jay linked, and you'll see I did mention, own, and test both types of Lithium Manganese. Also did a shootout here with answers and comments from AW comparing them with the Konion Sony "V" type.

Jay, when we say "Lithium Manganese" we are mainly distinguishing it from categories of "Lithium Iron Phosphate" and earlier (unsafe chemistry) "Lithium Cobalt."

There are distinctions and subtypes within each of the 3 categories that affect their performance on the above linked shootout.

For example, under the Lithium Cobalt chemistry category, their are Lithium Ion cylindrical, Lithium Polymer, Lithium Prismatic that all have unique properties and different additional components.

Lithium Iron Phosphate has the specific A123 Systems Inc "Nano-Lithium Iron Phosphate" and other variations in cathode/anode materials.

 

[Jay T]

T

So you suggest that AW is not only lying about the chemistry (for no evident gain, but I guess no real harm to him), but also giving us bad charging data that will halve the cycle life, and make him look bad when his cells don't last? :thinking: I guess I just don't see the motivation for that... :thinking:

His motives would be simple, world domination and the corruption of all youth resulting in a new socity rulled by hamsters. Why else would he produce oversized C cells unless directed to do so by the Hamster overloards.


Or

The same reason why he has C cells that don't fit in C lights without modification. The factory gave him something a little different than his specs called for.

 

[Jay T]

Jay, when we say "Lithium Manganese" we are mainly distinguishing it from categories of "Lithium Iron Phosphate" and earlier (unsafe chemistry) "Lithium Cobalt."

Right, "Lithium Manganese" is used as a catch all for smilier chemistries. I was just questioning which one IMR are based on this entry in your guide.

[*]c) "Safe" Lithium Nickel Cobalt Manganese cathode. This is close to the previous category, but this combination gives a bit more capacity but a bit less output rate. This is the Sony V (or VT in 26700 size), Sanyo, or Konion is another licensed brand made in Germany. Found in specific Makita, Ryobi, Bosch tool packs.
[/LIST]

• Has higher discharge rate of 5-7C (for 18650 cells that's ~10 Amps output). It should be charged at 1-2C (1.6 to 3.0 Amps).

• Moderate high stored capacity. 18650 size has ~1400mAh

• Higher 3.7V nominal, charging up to 4.1V (charging higher reduces cycle life from 800 to 300 cycles)
  

• Begins losing function (voltage drops) several years after manufacture due to Lithium crystalizing onto Lithium Nickel Cobalt Manganese Oxide cathode.

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• 
  
  
  Would it be best to use a hobby charger set to terminate at 4.1 or is charging to 4.2 best for them?

 

[mdocod]

Hello Jay T,

Just for the record, my Emoli cells settle to 4.10V after awhile just like everyone else's LiMn cells

 

[rizky_p]

from what i learn so far that the chemistry seems to be a little different between manufacturer hence different optimal termination voltage and resting voltage. Some of my Lifepo4 need to be charged passed 3.6v(3.65v, 3.7v etc) to gain its advertized capacity while others lifepo4 seems to be just fine with 3.6 CC/CV

just my 2 cent.

 

[Raoul_Duke]

Anybody with some true Emoli Lithium Manganese cells ever notice their cells relaxing the way these cells do?

Yes

Would it be best to use a hobby charger set to terminate at 4.1 or is charging to 4.2 best for them?

The lower you charge (4.1V vs 4.2V) then your cells "should" last a bit longer ( retain better cappacity over their lifetime.)

 

[Jay T]

Hello Jay T,

Just for the record, my Emoli cells settle to 4.10V after awhile just like everyone else's LiMn cells

Ok, then it's normal for them to relax. I was just curious as to if it was because the cells were the 4.1V subtype.

 

[LuxLuthor]

I think almost all the Lithium Cobalt and Lithium Manganese settle in the 4.1+ range, even if you charge them to 4.2

Honestly, since most people have a Lithium Cobalt charger that terminates at 4.2V, that's what most are going to use. I have a hard time believing that charging a model that specifies charge to 4.1 is going to have a significant deterioration if charged to 4.2V. What you could do is see where charge ends up after 30-60 mins, after charging to 4.2V, then use that for your custom termination voltage if your charger allows it to be specified.

 

[David Gretzmier]

I've got some ebay purchased GD name brand high drain 26650 cels running in electrolumens 3 x mce mag mod, I will test them tomorrow to confirm charged state ( I checked a few weeks ago and it was 4.25 I believe) and rested state 48 hours later. I tested these things over a period of days and tested drain, and I remember them holding to 4.1 or so after blasting with 3 mce's for 15 minutes or so. i'll go back and read my posts.

 

[David Gretzmier]

huh, looking back at my post It looks like I ran it for 10 minutes and the drop was only from 4.25 to 4.23. this was pretty fresh off the charger, and I am not sure if 10 miuntes x 3 mce's is the same as resting a few days. i'll check back in when I've tested just plain old sitting around.

 

[Patriot]

His motives would be simple, world domination and the corruption of all youth resulting in a new socity rulled by hamsters. Why else would he produce oversized C cells unless directed to do so by the Hamster overloards.


Or

The same reason why he has C cells that don't fit in C lights without modification. The factory gave him something a little different than his specs called for.

LOL....this made made evening... I happen to think it was a perfect response too...