# Lithium IMR vs ICR vs IFR



## Kingnog (Jun 30, 2011)

Can someone please explain the difference between 14500 IMR, ICR and IFR battery types? Which would be best for a flashlight rated for 4.2v max?

I have checked out the huge battery sticky and couldn't find any of that information.


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## HKJ (Jun 30, 2011)

Maybe this table can help a bit (It is from one of my charger reviews):






ICR are the usual type of LiIon batteries.
IMR has less capacity and can deliver higher current.
IFR is a lower voltage.


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## 45/70 (Jun 30, 2011)

Better yet, Battery University offers a wealth of information, not only relating to Li-Ion cells, but other rechargeable cells and batteries, as well.

Dave


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## Kingnog (Jun 30, 2011)

Thanks for the literature, but I'm still confused....do I want a higher current with less capacity? Do I want the "usual" type (ICR)? 

Which one should I use for my 4.2v 1x14500 flashlight? I should get a protected one, right?


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## HKJ (Jun 30, 2011)

Kingnog said:


> Thanks for the literature, but I'm still confused....do I want a higher current with less capacity? Do I want the "usual" type (ICR)?
> 
> Which one should I use for my 4.2v 1x14500 flashlight? I should get a protected one, right?


 
Most people uses ICR cells, these are the only type you can get with protection.


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## Helmut.G (Jun 30, 2011)

IFR have a much longer life expectation than the two other types (both in cycles and in time) from what I've read and can supply extreme power levels without problems (more than IMR). they are also less dangerous if abused.


for a low power flashlight ICR will give you max runtime, IFR maximum safety.


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## jasonck08 (Jun 30, 2011)

First off, this will explain their names:

In the case of IxR, the first Letter "I" just means that the cell is a Li-ion rechargeable. Second letter refers to the cathode material. The last letter "R" just means the cell is round.

ICR = Li-ion Rechargeable, the "C" = Cobalt.

IFR = the "F" stands for the element "Fe" which is Iron

IMR = the "M" stands for Manganese, or "Mn".

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Unless you are trying to draw a lot of current from the cell, most people use protected ICR cells to power their lights because they offer the most energy density. IMR's are more often used for higher current applications, and these cells require more care because there is no protection circuit and its easier to over discharge the cell.


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## Therrin (Feb 7, 2013)

I had been wondering about this on another thread and never got an answer. This is pretty informative, thanks! 

I just got some 26650's off batteryspace. They're ICR's, but I don't believe they're protected =(


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## eusty (Feb 7, 2013)

Yeah nicely put. I've read about batteries a bit but never seen the abbreviations explained 

Sent using Tapatalk 2.


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## Joe Talmadge (Feb 7, 2013)

Kingnog said:


> Can someone please explain the difference between 14500 IMR, ICR and IFR battery types? Which would be best for a flashlight rated for 4.2v max?



Kingnog, "best" has to do with a number of factors -- not just what the flashlight is rated for, but other factors could include how responsible you will be in maintaining your cells, whether the light has built-in over-discharge circuitry, how much current the light draws on high. In other words, if you really want to learn more, it might help to ask this question in the context of a particular light.

I can tell you what we do know already. For a light that can handle 4.2V, we can look at HKJ's chart in the 2nd post and know that we'd go with ICR or IMR (we might as well drive the light at the max voltage supported, unless we know that the light is tuned for a different voltage, the way some zebralights seem to be tuned for NiMH instead of Li Ion). These two have some tradeoffs versus each other: 

ICR has relatively more power density than IMR. That is, both are 4.2V max, but the ICR will be rated at higher mAh. That means that under many conditions -- but not all conditions, see below -- the ICR will probably last longer.

IMR can support higher discharge rates than ICR. There are some lights -- witness the 1x16340 lights that are putting out 500+ lumens -- that pull amps that are at the edge, or over the edge, of what an ICR can support, whereas an IMR won't even be breathing hard. Also, it is common that when you stress an ICR this much, voltage sags and it runs less efficiency, so that in extremely high-drain demanding applications, it sometimes happens that an IMR can last longer than an ICR, even though the ICR has a higher mAh rating.

ICR is less safe than IMR. That is, ICRs can go into thermal runaway easier, and that can mean an extremely unpleasant reaction ... in the extreme, your flashlight blowing up or house going on fire. Much more difficult to get an IMR to do that. As a result, ICR can be bought with or without a protection circuit. Depending on your state of knowledge -- right now, based on your questions, I don't think you should consider buying any Li Ion unless you learn a bit more -- you might stick with a protection circuit for now, if you go ICR. IMRs do not have protection circuits, because their chemistry is safer; you might ruin the battery if you mishandle it, but you probably won't blow it up.


My general guidelines:
- Understand proper care and handling of Li Ion
- Buy quality cells and a quality charger. If you're tempted to cheap out, don't play with Li Ions at all
- I stick with protected LiCo anywhere that works well. In a light that has circuitry that prevents overdischarge, and it can benefit from IMR's greater discharge rates, I go IMR. If the light can't handle a 4.2V ICR/IMR well, but can handle a 3.6V IFR, then I go with IFR. I don't do unprotected LiCo. Those are just my personal guidelines, there are smarter people than me with different ones.


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## tobrien (Feb 9, 2013)

HKJ said:


> Most people uses ICR cells, these are the only type you can get with protection.



purely out of curiosity, surely it wouldn't _hurt_ to put protection on an IFR cell though, right?


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## HKJ (Feb 9, 2013)

tobrien said:


> purely out of curiosity, surely it wouldn't _hurt_ to put protection on an IFR cell though, right?



No, it would be perfectly fine.
IFR is often used for high current draws, this makes the protected more expensive.
The amount of IFR cells sold for stand alone use is probably a very small fraction of the number of ICR cells, making it a much less interesting business.


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## VidPro (Feb 9, 2013)

^ i have always wondered that too. a high amp protection. I also wonder if it might be usefull in the li-fe , or if it is deemed totally unnessisary.


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## tobrien (Feb 9, 2013)

HKJ said:


> No, it would be perfectly fine.
> IFR is often used for high current draws, this makes the protected more expensive.
> The amount of IFR cells sold for stand alone use is probably a very small fraction of the number of ICR cells, making it a much less interesting business.



ohhhhhhh okay! your explanation was *perfect*, thank you


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## ragnarok164 (Jul 13, 2013)

Are there any difference between lMR and lCR cells for self-discharge? I think Li-ion based cells have a lower self-discharge rate than Ni-MH cells right?


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## reppans (Jul 13, 2013)

ragnarok164 said:


> .....I think Li-ion based cells have a lover self-discharge rate than Ni-MH cells right?



Hmmmm, not if their both stored at 100% and at room temp. An Eneloop is said to self-discharge about 15% (recoverable) after a year while a Li-ion will suffer a permanent capacity loss of ~ 20% (per BattUniv.). But the Li-ion will probably do better if both are stored a 40%.


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## StorminMatt (Jul 14, 2013)

HKJ said:


> No, it would be perfectly fine.
> IFR is often used for high current draws, this makes the protected more expensive.
> The amount of IFR cells sold for stand alone use is probably a very small fraction of the number of ICR cells, making it a much less interesting business.



Another thing to keep in mind about a hypothetical protected IFR cell is that, because an 18650 can potentially generate 30+ amps on a continuous basis, the protection circuit would inevitably have to be physically much bigger than that found on an ICR battery. This would either make the battery too big for many 18650 applications. Or it would significantly reduce the capacity of the battery by cutting into real estate formerly occupied by actual active material in the battery. And because IFR cells naturally have less capacity than ICR cells, further capacity reductions resulting from the need to make room for protection circuitry could render IFR batteries fairly useless for many applications. Of course, I merely used the example of an 18650. Other battery sizes (26650, 32650, etc) would similarly suffer if they were protected.


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## TEEJ (Jul 15, 2013)

/\ /\ /\

Excellent point.

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I'll add that the suggestion to specify what light its for would help too, because the circuits on some lights will allow the light to be brighter with more voltage, and/or more amps, etc.

That means that the extra watt hours, etc, can either make a light run longer, or, brighter but shorter, etc.

Depending on your priorities...you may be happy with a given output of light, and just want it to run as long as possible, or, you might want to maximize the brightness and are happy with a shorter run time to get it, etc.


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## LuxLuthor (Jul 15, 2013)

Back years ago when I was actually posting useful information, I did two threads that I believe are still accurate to date. Battery capacity has increased, but the concepts remain the same. Back then we used to walk 5 miles to school, you were cool if you had a Superman Lunchbox, and none of the single Lithium Ion cells were freely available. Their use and discovery was driven largely by the RC (cars, planes, boats, etc.) crowd who knew tons more about LiPo/Li-Ion batteries than CPF members. Anyone serious about cutting edge batteries needs to join RC Groups if you haven't already. Ditto on reviewing Battery University several times--the more you learn, the more you understand of what you read before but went over your head early on.

As far as I can tell here at CPF, HKJ is the "man" now on all things Li-Ion batteries here at CPF. :bow:

The game back in 2006-2007 was trying to figure out which power tool packs had which type of cells that we manually took apart and harvested the cells...hopefully without causing an explosion with our dead shorts when ripping off the securely connected battery tabs. The now bankrupt A123 Systems had the prized Nano Lithium Iron Phosphate cells that really kicked *** in terms of amps, durability, fast recharging, etc. The guys could get their RC Planes in the air and supercharge a backup set of batteries ready to use when the plane landed. Anyway, people can look at these links if they want pretty pictures of the batteries and my description of battery categories. God, has it really been that long ago?



*Lithium Ion Categories
*



* Lithium Ion "Safe" Chemistry Performance Shootout @ 5, 10, 15 Amps. *


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## GehenSienachlinks (Jan 1, 2014)

So the Panasonic 18650pf should be one the safest unprotected batteries available now . I'm not sure which two chemistries it uses is it IMR and Li-ion ?


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## kosPap (Jan 2, 2014)

found this soemwhere:

the PD is 22mΩ with a Lithium Nickel Cobalt Aluminium core, (PD is the cell the PF repalces)
the PF is 35mΩ with a Lithium Nickel Manganese Cobalt Oxide core.

Both are termed Hybrid technology and it obvious why


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## GehenSienachlinks (Jan 12, 2014)

The 18650PF is LiNiCOMnO2 /NMC / lithium-manganese-cobalt-oxide. There is another cell which I have not heard much about 
 Sony US18650NC1 2900mAh  , maybe HKJ will do a review on it soon so we can compare it with the PF .

I believe the sony 18650 is an / IMR / LiMn2​O4 -----------​ / LMO / spinel / that's the first 2900mah IMR I have seen .
Continuous maximum discharge current: 8-10A .


[h=2][/h][h=1][/h]

http://batteryuniversity.com/learn/article/the_high_power_lithium_ion


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## bltkmt (Jul 6, 2017)

Joe Talmadge said:


> Kingnog, "best" has to do with a number of factors -- not just what the flashlight is rated for, but other factors could include how responsible you will be in maintaining your cells, whether the light has built-in over-discharge circuitry, how much current the light draws on high. In other words, if you really want to learn more, it might help to ask this question in the context of a particular light.
> 
> I can tell you what we do know already. For a light that can handle 4.2V, we can look at HKJ's chart in the 2nd post and know that we'd go with ICR or IMR (we might as well drive the light at the max voltage supported, unless we know that the light is tuned for a different voltage, the way some zebralights seem to be tuned for NiMH instead of Li Ion). These two have some tradeoffs versus each other:
> 
> ...



I found this very helpful. Thanks.


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## kingjohn (Sep 13, 2017)

Thanks for this valuable info!
Do you know if it is dangerous in case the flashlight wants to draw more current, than the battery can deliver?

Will this stress the battery in any way?

(In detail I want to know this for unprotected Panasonic 3400mAh cells )


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