# LiFeP04 vs. LiMN vs. LiNiMnCoO2



## snakyjake (Nov 23, 2010)

These are the three battery chemistries mentioned as safe lithium rechargeables.



I'm wondering if one is more safe than another?



Which can handle over discharging better? 



Which is safer for charging?



Which one has more capacity?



Which one is better for the typical high output (100-200 lumen) LED light?



What is the availability of these chemistries in batteries for our lights (RCR123A/18650/etc)?



Thanks,

Jake


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## magudaman (Nov 16, 2011)

Lame, I can't believe no one responded to this in over a year.

Anyhow one to your questions

I'm wondering if one is more safe than another?
Lifepo4 is considered the safest of those three. Less likely to spit fire in many conditions


Which can handle over discharging better? 

Back to safety again, lifepo4 is the winner here again


Which is safer for charging?

Lifepo4


Which one has more capacity?

In what regard? Wh/KG, Volumetric, etc?

LiNiMnCoO2 is really the winner of those two anyhow it carries more power in a smaller form factor than the other two.

Which one is better for the typical high output (100-200 lumen) LED light?

I'm done, check out battery university for more information, its a great read:

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






What is the availability of these chemistries in batteries for our lights (RCR123A/18650/etc)?



Thanks,

Jake


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## KiwiMark (Nov 17, 2011)

magudaman said:


> Lame, I can't believe no one responded to this in over a year.



Actually I'd bet there were helpful replies back when this was posted. Since then there has been a server crash and many posts were lost.


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## Battery Guy (Nov 17, 2011)

snakyjake said:


> These are the three battery chemistries mentioned as safe lithium rechargeables. I'm wondering if one is more safe than another?



Safety is relative and difficult to quantify. I would say that LiFePO4 is "safer" only because cells made with that material have significantly lower energy density.



snakyjake said:


> Which can handle over discharging better?



None. The damage that occurs due to over discharge happens at the negative electrode, and all lithium-ion cells use essentially the same negative electrode. 



snakyjake said:


> Which is safer for charging?



LiFePO4 and LiMn2O4 cannot be overcharged. That is to say that you can certainly charge them to a higher voltage, but you cannot put excess capacity into the cell by doing so. If you charge a cell with the Li(Ni,Co,Mn)O2 cathode to a higher voltage than it is specified for, you will extract excess lithium from the cathode, possibly leading to plating of metallic lithium on the anode and making the cell relatively unstable and unsafe.




snakyjake said:


> Which one has more capacity?



In order of increasing capacity and energy: LiFePO4, LiMn2O4, Li(Ni,Co,Mn)O2



snakyjake said:


> Which one is better for the typical high output (100-200 lumen) LED light?



Depends on how big you want your battery to be and how much runtime you want. If you are looking for something small that will have a relatively high drain rate on the cell, then the LiMn2O4 is probably best because cells made with that material are usually designed for high discharge rates. If you are looking for something that will have a long runtime, then something with the Li(Ni,Co,Mn)O2 cathode is probably best because cells that use this material are typically designed for high capacity, albeit lower discharge rates. I don't see much use for LiFePO4 cells, except perhaps for certain unregulated hotwire mods where the voltage happens to correspond well to a particular bulb.



snakyjake said:


> What is the availability of these chemistries in batteries for our lights (RCR123A/18650/etc)?



They are all pretty much widely available, although if you are looking for Li(Ni,Co,Mn)O2 cells you may have trouble finding anything other than 18650s. Check out the selection from AW.

Cheers,
BG


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## jtr1962 (Nov 17, 2011)

Battery Guy said:


> I don't see much use for LiFePO4 cells, except perhaps for certain unregulated hotwire mods where the voltage happens to correspond well to a particular bulb.


One reason I stick pretty much exclusively to LiFePO4 among the major lithium chemistries, besides its inherent safety, is the total life cycle cost. LiFePO4 can last for literally thousands of cycles, compared to a few hundred for the other lithium chemistries. Besides a much higher number of cycles, the calender life is much longer. This is actually the bigger selling point for me than the huge number of cycles. One thing which turned me off regarding the other lithium chemistries is the fact that they degrade within a few years whether they're used or not. This to me is unacceptable. I expect any cell I buy to be useable a decade or two later. So far it seems only three types of cells meet that requirement-NiCd, LSD NiMH, and LiFePO4. The jury is still out on LiFePO4, but indications are if not abused they will last well over a decade. The lower energy density is a price I'm willing to pay for longer service life.


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## Battery Guy (Nov 17, 2011)

jtr1962 said:


> One reason I stick pretty much exclusively to LiFePO4 among the major lithium chemistries, besides its inherent safety, is the total life cycle cost. LiFePO4 can last for literally thousands of cycles, compared to a few hundred for the other lithium chemistries.



High quality cells like those made by A123 can indeed have great cycle life. Low quality LiFePO4 cells, like a lot of the junk available online, can have terrible cycle life. 

The "inherent safety" stems from the low energy density. Charge a conventional lithium-ion cell with a LiCoO2 cathode so that it has the same total energy and it will have the same "inherent safety". 



jtr1962 said:


> Besides a much higher number of cycles, the calender life is much longer. This is actually the bigger selling point for me than the huge number of cycles. One thing which turned me off regarding the other lithium chemistries is the fact that they degrade within a few years whether they're used or not.



This is only true for poor quality cells or cells stored improperly. Good quality cells with LiCoO2 or variants have excellent calendar life. I have tested cells that sat on shelf in my lab for five years and they showed no significant loss in energy or power capability.



jtr1962 said:


> This to me is unacceptable. I expect any cell I buy to be useable a decade or two later. So far it seems only three types of cells meet that requirement-NiCd, LSD NiMH, and LiFePO4. The jury is still out on LiFePO4, but indications are if not abused they will last well over a decade. The lower energy density is a price I'm willing to pay for longer service life.



Two decades is a long time. I am not sure that LSD NiMH or any lithium-ion cell has been shown to meet those requirements.

Much of the touted advantages of LiFePO4 stem from the lower voltage and lower inherent energy density. For example, a high power A123 18650 has a total energy of 3.5 Wh, compared to an AW IMR high power 18650 which has a total energy of 5.7 Wh. If you charge the AW IMR cell to a lower voltage so that it has the same energy as the A123 cell, you will get most of the same advantages.

I guess that all I am saying is that there are indeed great LiFePO4 cells (e.g. A123) that have the attributes that you find appealing, but there are also garbage LiFePO4 cells. I just don't want others to think that LiFePO4 is synonymous with great cycle life and calendar life.

The other point I want to make is that most of the advantages of LiFePO4 come at a considerable hit on energy density, and most of these advantages can be replicated in traditional lithium-ion cells by simply charging them to a lower voltage.

Food for thought.

Cheers,
BG


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## jtr1962 (Nov 17, 2011)

Battery Guy said:


> The "inherent safety" stems from the low energy density. Charge a conventional lithium-ion cell with a LiCoO2 cathode so that it has the same total energy and it will have the same "inherent safety".


No, the inherent safety has nothing at all to do with the lower energy density. Rather, it has to do with the chemistry. In short, runaway exothermic reactions simply cannot occur with this type of battery. And the same characteristics which make the cell more stable chemically also give it longer cycle life. This is why these cells are used in power tools and electric vehicles, both applications where safety and life cycle cost are more important than absolute energy density.

I've little doubt there are junk LiFePO4 cells out there, just as there are junk LiCoO2. Since LiFePO4 isn't commonly used in cheap consumer applications though I would say the market for them is a lot less tolerant of junk, or at least so far I've yet to see any LiFePO4 cells I would call garbage. As with any battery, be aware of what you purchase, and verify manufacturer's claims.

As for calender lifetime, I have NiCd cells over 20 years old which charge just fine. LSD NiMH haven't been around long enough to determine their calender life, but I would think the same mechanisms which prevent self-discharge when stored for years will prevent deterioration. The verdict is still out on LiFePO4 also, but some things I've read suggest a potential calender life of several decades (assuming quality cells, of course).



> This is only true for poor quality cells or cells stored improperly. Good quality cells with LiCoO2 or variants have excellent calendar life. I have tested cells that sat on shelf in my lab for five years and they showed no significant loss in energy or power capability.


I'll take your word for this but I've personally yet to see any type of LiCoO2 cell not lose some capacity after even 12 months. This is why I avoid consumer products with built-in Li-Ion batteries like the plague. I figure chances are good in 3 years I'll have an expensive paperweight. Of course, 2 or 3 years is enough for the average person who will have already upgraded to something else before the battery suffers a noticeable capacity loss.

The big problem with your statement here is "This is only true for poor quality cells or cells stored improperly." A person buying a product with Li-Ion cells has no way of knowing if they're getting junk or not, and more importantly if the device is charging/discharging the cells properly. This is why I prefer cells which are somewhat tolerant of abuse, even for my own uses where I'll generally care for them properly. It's a shame LiFePO4 so far has lower energy density than LiCoO2 because to me that's really its only drawback, and the only reason it isn't used more. You may have no use for LiFePO4 personally, but it's very misleading to make a blanket statement like "I don't see much use for LiFePO4 cells, except perhaps for certain unregulated hotwire mods where the voltage happens to correspond well to a particular bulb."


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## Mr Happy (Nov 17, 2011)

Concerning energy density, the AW IMR26500 tested in the other thread is rated at 2300 mAh, while the K2 Energy LFP26650EV is rated at 3200 mAh. Given that the LFP cell is also rated for 12 A continuous discharge it does not seem to be at much of a disadvantage when compared.


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## jtr1962 (Nov 17, 2011)

Mr Happy said:


> Concerning energy density, the AW IMR26500 tested in the other thread is rated at 2300 mAh, while the K2 Energy LFP26650EV is rated at 3200 mAh. Given that the LFP cell is also rated for 12 A continuous discharge it does not seem to be at much of a disadvantage when compared.


I just purchased 8 of these to power a pair of bike lights. Just to add another data point, the 8 cells test out between 3179 and 3290 mAh at 0.2C ( 660 mA ). They only do about 125 mAh worse at 2C ( 6.6 amps ).

More interesting reading

_"A123 replaced the cobalt-oxide-based electrodes of conventional lithium-ion batteries with new nanostructured iron-phosphate electrodes. These phosphates are inherently safer than the cobalt-oxide-based chemistries, which have been known to suddenly burst into flames, destroying laptops and cell phones in the process and leading to massive recalls. The conventional cobalt materials also don't last very long--that's why laptop batteries have to be replaced every couple of years. The capacity of A123's batteries, in contrast, doesn't fade much with use. *Safe, long-lasting batteries are essential in cars, where they're expected to survive abusive conditions for a decade or more.*"_


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## Battery Guy (Nov 17, 2011)

jtr1962 said:


> No, the inherent safety has nothing at all to do with the lower energy density. Rather, it has to do with the chemistry. In short, runaway exothermic reactions simply cannot occur with this type of battery. And the same characteristics which make the cell more stable chemically also give it longer cycle life. This is why these cells are used in power tools and electric vehicles, both applications where safety and life cycle cost are more important than absolute energy density.



I understand what you are saying, but quite frankly it does have to do with energy density of the full cell, and how much delithiation of the cathode you need to reach that energy. If you charge one of the AW IMR cells 18650 cells to the same energy as an A123 18650, the exothermic reactions you speak of (the ones that liberate oxygen from the cathode) cannot occur either.

With respect to the use of LiFePO4 cells in power tools, the only company that still uses LiFePO4 cells is Black and Decker, and they have been shifting to other cell chemistries because LiFePO4 simply cannot compete for energy and power density. 

With respect to EVs, only the Chinese are using LiFePO4 for EVs, and not without significant safety issues. Want to see a demonstration of the "inherent safety" of LiFePO4 in EVs, look here. My point in showing that link is not to say that LiFePO4 is NOT safe, but rather to show that LiFePO4 CAN fail in an unsafe manner. Too many people think that just because they have a LiFePO4 battery that nothing can go wrong. 

LiFePO4 has its place in the world of lithium-ion. I think that it makes sense for large, stationary batteries, which is actually the direction that A123 is moving. There is a reason that no commercially available hybrid, plug-in hybrid or EV uses A123 cells...the performance just is not as good as can be achieve with other chemistries.



jtr1962 said:


> As for calender lifetime, I have NiCd cells over 20 years old which charge just fine. LSD NiMH haven't been around long enough to determine their calender life, but I would think the same mechanisms which prevent self-discharge when stored for years will prevent deterioration. The verdict is still out on LiFePO4 also, but some things I've read suggest a potential calender life of several decades (assuming quality cells, of course).



Possible, but you have to remember that all lithium-ion cells still use the same anode (negative electrode), and a lot of degradation in lithium-ion cells occurs at that electrode as well. LiFePO4 does not do anything to stop degradation mechanisms at the negative electrode that contribute to cycle and calendar life degradation.




jtr1962 said:


> I'll take your word for this but I've personally yet to see any type of LiCoO2 cell not lose some capacity after even 12 months. This is why I avoid consumer products with built-in Li-Ion batteries like the plague. I figure chances are good in 3 years I'll have an expensive paperweight. Of course, 2 or 3 years is enough for the average person who will have already upgraded to something else before the battery suffers a noticeable capacity loss.



Then you have had very, very bad luck my friend.



jtr1962 said:


> The big problem with your statement here is "This is only true for poor quality cells or cells stored improperly." A person buying a product with Li-Ion cells has no way of knowing if they're getting junk or not, and more importantly if the device is charging/discharging the cells properly. This is why I prefer cells which are somewhat tolerant of abuse, even for my own uses where I'll generally care for them properly.



If you are buying consumer electronics from well known companies, you can be pretty certain that the cells are of reasonable quality and being charged/discharged correctly. However, I must admit that there has been a big push to maximize the capacity of cells for consumer electronics, and often this is done at the detriment of cycle life.



jtr1962 said:


> It's a shame LiFePO4 so far has lower energy density than LiCoO2 because to me that's really its only drawback, and the only reason it isn't used more. You may have no use for LiFePO4 personally, but it's very misleading to make a blanket statement like "I don't see much use for LiFePO4 cells, except perhaps for certain unregulated hotwire mods where the voltage happens to correspond well to a particular bulb."



You are right, it is a shame that LiFePO4 doesn't have a higher density. But I stand by my statement for this forum, except perhaps I should have qualified that I was talking about flashlights in particular. I do think that LiFePO4 has a place in the family of lithium-ion, but there are few applications that can utilize its niche advantages. 

If I were wrong, A123 Systems would be taking over the world. As it stands, they are struggling to say the least. And they will continue to struggle until they can move beyond LiFePO4.

Cheers,
BG


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## jtr1962 (Nov 17, 2011)

Battery Guy said:


> I understand what you are saying, but quite frankly it does have to do with energy density of the full cell, and how much delithiation of the cathode you need to reach that energy. If you charge one of the AW IMR cells 18650 cells to the same energy as an A123 18650, the exothermic reactions you speak of (the ones that liberate oxygen from the cathode) cannot occur either.


The point is the exothermic reactions can't occur with a LiFePO4 cell regardless of what you do. That's the definition of inherent safety, and that's the big selling point for me here. You can design in all the protection circuitry you want but fact is sometimes circuits fail. I prefer to use a cell which won't self disassemble if something goes seriously wrong with the protection circuitry.

Honestly, yours is the first statement I've heard, ever, saying that lower energy density is the reason LiFePO4 is safer. This is especially puzzling because there seems to be some overlap in energy density between the IMR cells and LiFePO4, and yet LiFePO4 is still safer. I'd love for a CE to chime in about this because I always thought the sole reason LiFePO4 was safer was the chemistry.



> With respect to EVs, only the Chinese are using LiFePO4 for EVs, and not without significant safety issues. Want to see a demonstration of the "inherent safety" of LiFePO4 in EVs, look here. My point in showing that link is not to say that LiFePO4 is NOT safe, but rather to show that LiFePO4 CAN fail in an unsafe manner. Too many people think that just because they have a LiFePO4 battery that nothing can go wrong.


I did a little research. Basically, if you read the article, it seems shoddy workmanship and inattention to detail was the cause of the fire. To quote from the article: _"The report adds that the battery cells on the car, made by Zhejiang Wanxiang Group, themselves were not responsible for the accident, but were employed improperly for an electric taxicab."
_
If anything, this is yet another testament to the inherent safety of LiFePO4. Despite the abuse given to these cells, they failed to explode. Due to the huge current _any_ EV battery puts out a fire can certainly start. But there was no explosion like there might have been if LiCoO2 had been used.



> LiFePO4 has its place in the world of lithium-ion. I think that it makes sense for large, stationary batteries, which is actually the direction that A123 is moving. There is a reason that no commercially available hybrid, plug-in hybrid or EV uses A123 cells...the performance just is not as good as can be achieve with other chemistries.


They also make sense for people like me who are looking for a cell they can build into a project, then not think about it for the next decade or more, or worry about it blowing up if something in the charging circuit fails.

As for automotive uses, maybe having to assemble a few thousand 26650 cells into a battery pack is the reason A123's cells aren't being used? If A123 Systems were smart, they would start making larger single cells so that a few dozen could be used for an EV battery pack. Energy density isn't an issue here because "safer" conventional Li-Ion cells, such as the LG Chem cells being used in the Volt, also have lower energy density. To the best of my knowledge nobody is using or planning to use higher energy density LiCoO2 in EVs.



> Possible, but you have to remember that all lithium-ion cells still use the same anode (negative electrode), and a lot of degradation in lithium-ion cells occurs at that electrode as well. LiFePO4 does not do anything to stop degradation mechanisms at the negative electrode that contribute to cycle and calendar life degradation.


I don't have a good answer for you other than to say that the primary degradation mechanism likely occurs at the cathode. If anode degradation were important, the A123 System cells would suffer regular annual capacity loss, and yet tests show they don't. Maybe anode degradation comes into play over a time span of decades?



> Then you have had very, very bad luck my friend.


Me and everyone else I've known. It's more like you've either had exceptionally good luck, or you've given your cells far better treatment than most people, including myself, ever would. Basically, I expect a rechargeable cell to be ready to use when I want to use it, even if it's been sitting in a drawer for years. That means it either retained a charge, or retained the ability to be charged to near new capacity, perhaps after a few break-in cycles. So far, only NiCd, LSD NiMH, and LiFePO4 have been able to cope with those demands. I've seen all other types of rechargeable lithiums degrade. Same thing with most conventional NiMH.



> If you are buying consumer electronics from well known companies, you can be pretty certain that the cells are of reasonable quality and being charged/discharged correctly. *However, I must admit that there has been a big push to maximize the capacity of cells for consumer electronics, and often this is done at the detriment of cycle life.*


You hit the nail on the head as to both why LiFePO4 isn't used in consumer electronics, and why also it seems that new devices have worse cycle life than older ones.



> You are right, it is a shame that LiFePO4 doesn't have a higher density. But I stand by my statement for this forum, except perhaps I should have qualified that I was talking about flashlights in particular. I do think that LiFePO4 has a place in the family of lithium-ion, but there are few applications that can utilize its niche advantages.
> 
> If I were wrong, A123 Systems would be taking over the world. As it stands, they are struggling to say the least. And they will continue to struggle until they can move beyond LiFePO4.


Isn't A123 Systems doing research which they claim would eventually increase the energy density of LiFePO4 by something like a factor of four? In any case, A123 Systems signature product _is_ their LiFePO4 cell. IMO they need to focus on improving that, not become yet another player manufacturing the other types of lithium cells. Also, if you ask me, I'd say within a decade chemical cells of all types will be obsolete as ultracapacitors outpace them in both energy and power density.


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## Battery Guy (Nov 17, 2011)

jtr1962

I simply leave you with this point: if LiFePO4 were all it were cracked up to be then everyone would be using. In fact, the opposite is true. The early adopters (e.g. Black and Decker) are moving away from it, and no major US, Japanese or European car company is using or even considering using it. 

If it works for you, then go for it. I stand by my original opinion that LiFePO4 is highly overrated and has only niche applications where it excels. 

I also predict that A123 and other LiFePO4 based companies will fail in the next 5 years if one of the following two things does not happen:

1.) they move beyond LiFePO4 (it is not theoretically possible to improve its energy density beyond what it already is)
2.) a new, currently unknown, application is found that is perfect for LiFePO4-based lithium-ion cells

Government funding and investor patience is running out. LiFePO4 was an obsolete chemistry when it was developed (with all due respect to Goodenough and Hydro-Quebec), and it is still an obsolete chemistry. 

That being said, my advice and opinions on this forum are free, and are probably worth slightly less than that.

Cheers,
BG


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## jtr1962 (Nov 17, 2011)

Battery Guy said:


> If it works for you, then go for it. I stand by my original opinion that LiFePO4 is highly overrated and has only niche applications where it excels.


Basically, I had one of two alternatives which met my requirements-four of the 26650 LiFePO4 cells I linked to earlier, or 16 AA Eneloops. The battery pack for my bike headlight needed a capacity of roughly 40 W-hrs, it needed to be inherently safe from explosions, and it needs to last at least ten years with minimal attention. That left me with basically two choices-LSD NiMH or LiFePO4. I'm not aware of anything else which would have met the last two requirements, except maybe NiCd (which would have been too heavy/bulky). Charging 16 AA Eneloops in a series arrangement would have presented unique issues, although I might have gotten away with no balancing due to the good capacity match between cells. LiFePO4 presented less of an issue. Charging circuit is a simple CC/CV setup, and I bought a board to protect against overcharge/overdischarge for $7. I also saved a little weight over using 16 Eneloops. Cost in both cases was about the same, and no more than any of the other types of lithium chemistries. Sure, if I had chosen LiCoO2 I could have used 4 18650s instead of 4 26650s, saved a bit of space and weight. The cost though would have been peace of mind thinking the cells might explode, plus the need to replace the battery pack at least every few years.

I can't imagine I'm the only one who thinks like this. If LiFePO4 currently only has niche uses, then perhaps it's because, like LSD NiMH, not a whole lot of people are even aware of it. I know I wasn't until I joined these forums.



> I also predict that A123 and other LiFePO4 based companies will fail in the next 5 years if one of the following two things does not happen:
> 
> 1.) they move beyond LiFePO4 (it is not theoretically possible to improve its energy density beyond what it already is)
> 2.) a new, currently unknown, application is found that is perfect for LiFePO4-based lithium-ion cells


I'll add to your list: 3) An EV using one of the other lithium chemistries explodes.



> Government funding and investor patience is running out. LiFePO4 was an obsolete chemistry when it was developed (with all due respect to Goodenough and Hydro-Quebec), and it is still an obsolete chemistry.


Lead-acid, carbon-zinc, and even alkaline are 3 battery chemistries which by all rights should be obsolete given that we have superior alternatives, and yet they're still around. Fact is for now LiFePO4 doesn't really have any real competitors in the areas it excels (life cycle cost, safety and power density). Will that change in 5 years? Sure, that's an eternity when it comes to technology. I'm honestly hoping LiFePO4 becomes totally obsolete, along with every other type of chemical battery, in favor of ultracaps.


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## Mr Happy (Nov 17, 2011)

jtr1962 said:


> ...it needs to last at least ten years with minimal attention


Isn't that a rather tall order for any cell? I mean, I can understand a ten year shelf life, but ten years with a cell in daily use such as on a bike? I am sure eneloops can't do that, and I'm not sure what can. Almost all cells on the market of any chemistry have a working life of 3-5 years max when in regular use. They wear out and you have to replace them with fresh ones. That's just how it goes.


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## jtr1962 (Nov 17, 2011)

Mr Happy said:


> Isn't that a rather tall order for any cell? I mean, I can understand a ten year shelf life, but ten years with a cell in daily use such as on a bike? I am sure eneloops can't do that, and I'm not sure what can. Almost all cells on the market of any chemistry have a working life of 3-5 years max when in regular use. They wear out and you have to replace them with fresh ones. That's just how it goes.


I've been using the same set of four Eneloops in my current, crappy bike light for three years. They're showing absolutely zero signs of degradation after maybe 250 cycles ( I recharge generally every other ride). Maybe I'll do a break-in cycle soon on my C9000 just to see how their capacity compares to the value I recorded when they were brand new. I've little doubt I could continue to use these same four cells at least until I hit the 1000 cycle mark, at which point they would be in service over a decade. Sorry, but I don't buy into the notion that you should only get 3 to 5 years out of a rechargeable battery, even if the cycle count is low. Old school NiCads regularly lasted at least a decade if not abused. Even lead-acid can last that long if you don't deep discharge it or keep it on float charge. I purposely only buy products which take standard AAAs/AAs, rather than built-in Li-Ion packs, for the simple reason I don't want a paperweight a few years down the road when the battery stops taking a charge, and a new one is either unavailable, or costs almost as much as buying new.

I don't mind if a battery wears out because of cycling, even if it's only a year old. I do mind though if a cell only has 50 cycles, but can't be charged any more when it's only 3 years old because it degraded internally. Bottom line-I favor cells where cycle count is the primary wear mechanism.


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## Battery Guy (Nov 18, 2011)

Hi jtr1962

I know what the marketing material says, but no lithium-ion cell is inherently safe from explosions. If you get an internal short circuit and flash the electrolyte, the cell is going to vent. And if the vent design or implementation is poor, the cell will overpressurize and explode. I totally understand the issue with exothermic decomposition of the cathode, and that delithiated LiFePO4 is much, much more stable than other lithium-ion cathodes, but the fact remains that you have energy stored in a can with a flammable, volatile electrolyte. Until someone figures out a new electrolyte system, no lithium-ion system is "inherently safe". With the exception of A123 and Valence, most of the LiFePO4 cells I have looked at are pretty poorly constructed and use pretty crappy LiFePO4 material. 

I am just saying that you need to be careful and don't put your faith in the idea that LiFePO4 is inherently safe. Very well made LiFePO4 are extremely robost and have great cycle life. But unless you do your due diligence and find those cells, you are likely to get pretty shoddy stuff.

That being said, from a safety perspective, I guess I would rather have a shoddy LiFePO4 cell than a shoddy LiCoO2 cell.

With respect to your cycle life demands, I agree that the lithium-ion cells designed and sold for consumer electronics are pretty poor. But that is not inherent to the chemistry. There are plenty of companies making lithium-ion cells for EVs, plugin hybrids and hybrids that use higher energy density cathode materials and have demonstrated thousands of cycles. There is simply not enough demand for high cycle life lithium-ion cells for consumer electronics. Everyone wants to maximize energy density.

But for your application, given your cycle life requirement and your willingness to use a larger pack, sounds like LiFePO4 is right for you, provided you find good quality cells.

Cheers,
BG


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## Battery Guy (Nov 18, 2011)

Mr Happy said:


> Concerning energy density, the AW IMR26500 tested in the other thread is rated at 2300 mAh, while the K2 Energy LFP26650EV is rated at 3200 mAh. Given that the LFP cell is also rated for 12 A continuous discharge it does not seem to be at much of a disadvantage when compared.



Hi Mr. Happy

Your example comparing the K2 Energy LFP26650EV to the AW IMR 26500 is not quite accurate because the LFP26650EV is an "energy" cell, whereas the AW IMR 26500 is a "power" cell. You would be better off comparing the K2 Energy LFP26650P cell, which is a power cell with a 2600 mAh capacity. 

Best to compare apples to apples. For a given cell design that provides a certain C-rate, the energy density of LiFePO4 is approximately 60% of a conventional lithium-ion cell.

A great example can be seen when comparing the A123 18650 with a high power Sanyo 18650. Both are designed for power tools. Take a look at this Ragone plot:







You can see that both have nearly identical C-rate performance, but the A123 cell has ~60% of the total energy of the Sanyo cell.

A good rule of thumb is that it takes three LiFePO4 cells to equal the energy of two conventional lithium-ion cells, all things being equal (i.e. same cell size and form factor, same C-rate, etc...).

Cheers,
BG


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## LEDAdd1ct (Nov 18, 2011)

Have I mentioned lately how much I enjoy reading the highly intelligent discourse of our members? Holy cow, we have some bright people on this forum!


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## jtr1962 (Nov 18, 2011)

Battery Guy said:


> That being said, from a safety perspective, I guess I would rather have a shoddy LiFePO4 cell than a shoddy LiCoO2 cell.


That's actually my point. Lately it seems in the interests of greater capacity and/or lower cost, a lot of cells of all chemistries are garbage. The difference is that a garbage LiFePO4 or NiMH cell is far less likely to fail explosively than a garbage LiCoO2 cell.



> With respect to your cycle life demands, I agree that the lithium-ion cells designed and sold for consumer electronics are pretty poor. But that is not inherent to the chemistry. There are plenty of companies making lithium-ion cells for EVs, plugin hybrids and hybrids that use higher energy density cathode materials and have demonstrated thousands of cycles. There is simply not enough demand for high cycle life lithium-ion cells for consumer electronics. Everyone wants to maximize energy density.


I came across this which I think you'll find interesting. The relevant part regarding cycle life: _"Most other EVs are utilizing new variations on lithium-ion chemistry that sacrifice energy and power density to provide fire resistance, environmental friendliness, very rapid charges (as low as a few minutes), and very long lifespans. These variants (phosphates, titanates, spinels, etc.) have been shown to have a much longer lifetime, with A123 expecting their lithium iron phosphate batteries to last for at least 10+ years and 7000+ charge cycles, and LG Chem expecting their lithium-manganese spinel batteries to last up to 40 years."

_It seems regardless of chemistry, there is always the trade off of power density/cycle life versus energy density. I also find it incredible that LG Chem expects a service life of up to 40 years for their cells. Off topic, but I read elsewhere that the greater reliability of EVs versus ICEs might mean a paradigm shift where people actually expect all the major components of their vehicle, including the battery, to last 30 or 40 years with routine maintenance.



> But for your application, given your cycle life requirement and your willingness to use a larger pack, sounds like LiFePO4 is right for you, provided you find good quality cells.


I did look at several options, including these. 3 of these cells would have worked instead of 4 of the ones I chose. They even claim 600 cycles to 80% capacity. My main concern though was calender life. I figured I had a better chance of hitting a decade or more of service life with LiFePO4.


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## Battery Guy (Nov 18, 2011)

jtr1962 said:


> It seems regardless of chemistry, there is always the trade off of power density/cycle life versus energy density. I also find it incredible that LG Chem expects a service life of up to 40 years for their cells.



I am pretty skeptical of the 40 year prediction for the LG Chem cells as well. Although, I was recently at a conference where independent testing by a national lab showed some extremely impressive data on the LG Chem EV cells, as well as a few cells from other non-LiFePO4 manufacturers. Not sure that I would extrapolate the data 40 years, but I was encouraged that these might realistically last 10 years or so.

Cheers,
BG


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## germanium (Dec 25, 2011)

About the _lithium-manganese spinel batteries used in the Chevy Volt, They have already proven to be a safety hazard by errupting into flames 2 weeks after a crash test was done. Cause in this case was in fact determined to be the batteries. While it may be possable to create an unsafe condition for LiFePo4 batteries you have never heard of a true LiFePo4 powered hybrid car bursting into flames due to a battery malfunction where the battery itself ignites on its own after receiving abuse or been involved in a crash. That does not mean that there could not be a fire but it would not be caused by the battery itself igniting first. Fire could be caused by an electrical short which ignites the insulatin of the wiring due to the very high current capacity of LiFePo4 batteries but this is not the fault of the battery itself bursting into flames as it was with the Chevy Volt.

LiFePo4 still seemes to be the safest option & higher capacity is possable with this chemestry as proven by the LFP123 batteries from K2. These actually performed up to my expectation of what any lithium ion battery should have been capable of but till the K2 experiment I ran none lived up to as far as the CR123a battery size was concerned. All fell short by a substantial amount but not the K2's. The K2 LFP123 batteries do exchange current capacity for energy density though in this particular size. These are not the high current batteries that K2 makes in thier other sizes & are only rated for Cx2 for discharge rate. But under the circumstances I can see why they made that decision. Note that all the other K2 battery sizes are rated for greater than Cx2 discharge rates, even thier high energy versions as opposed to thier high power cells._


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## cy (Nov 25, 2013)

Battery Guy said:


> jtr1962
> 
> I simply leave you with this point: if LiFePO4 were all it were cracked up to be then everyone would be using. In fact, the opposite is true. The early adopters (e.g. Black and Decker) are moving away from it, and no major US, Japanese or European car company is using or even considering using it.
> 
> ...



two years later .. looks like your prediction of A123 going out of business has come to pass. but you missed the beginning of LiFePO4 use for 12v motorcycle batteries, which dwarfs market size for electric car batteries. 

weight savings of say 30-40lb means little to most folks unless you are part of a tiny group of light weight high performance cars like 911 owners. but saving 10 to 15lb on a motorcycle is HUGE! 

yes there are LOTS of folks willing to spend say $225 to save 10lb+ on their high tech motorcycles. when compared to folks spending $$$ for carbon parts to save a few oz. vs dropping 10+lb in one stroke is a bargain. 

the speed of adoption has caught a number of major battery mfg by surprise. competition is hotting up as more and more 12v LiFePO4 mfg hits the market place. 

LiFePO4 is the only li-ion battery that drops in with NO modification to almost any 12v vehicle. ALL charging system designed to support 12v lead acid batteries mates perfectly with 12v LiFePO4 batteries. 

LiCo's voltage of 4.2v max charge x 3 = 12.6v which puts cells in danger from overcharge and thermal runaway (explosion) 4.2v x 4 = 16.8v or too high for 12v motorcycle or automotive. 

12v LiFePO4 reaches full charge at 14.6v, but quickly drops to 13.3v range at first discharge. then stays almost flat during discharge cycle. so effective operating range for 12v LiFePO4 is 13.3v (90%) to about 12.4v (10%) .. or a perfect match for all charging systems designed to support PB which puts out 13.8v to 14.2v range. some modern motorcycles operate slightly higher voltage. 

gotta disagree with you assessment about LiFePO4 dangers being lower primarily due to lower energy densities. LiFePO4 discharges at HUGE amp rates and is inherently safe .. requiring wild abuse to catch on fire. I'm not aware of a single instance where LiFePO4 caught on fire in any vehicle where fire was not caused by a dead short. either internally and/or from dead short to positive from a wreck and/or poor installation. there's been many instances of LiFePO4 batteries melting from being charged at excessively high rates in excess of 7C. 

vs there's a long history of LiCo cells going into thermal runaway (Boeing 787) with LOTS damage. including almost burning down homes. unless something has drastically changed, the biggest danger for LiCo occurs during charging.


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## jtr1962 (Nov 25, 2013)

I'll add that solar lighting seems to be another niche use where LiFePO4 is catching on big time. Anyone who has ever tried solar outdoor lighting has had issues due to battery failure. NiCd and NiMH just don't hold up in this type of use where they may be subject to overcharge, possible overdischarge, temperature extremes, and hundreds of cycles annually. A possible exception might be very robust cells like Eneloops but those are often too costly for this application. Moreover, the voltages of NiMH and NiCd are not well matched in this application. Boost circuits to drive the LEDs are required. Given the cost constraints, these are often quite inefficient. And the solar cells on many outdoor solar lights output ~3.6 volts. This is too high for 2 cells in series but too low for 3 cells. LiFePO4 on the other hand is a perfect match here. The 3.6 volts coming from the solar cells is perfect for charging with no possibility of overcharging. And the flat ~3.2V discharge curve is perfect to drive LEDs without any additional circuitry. Moreover, the energy density is superior to the NiCad batteries typically used in this application. Usually a pair of Nicads of about 700 mAh are used. This gives about 1.7 watt-hours but often 1/3 of this is lost in the boost circuit, delivering only 1.2 watt-hours to the LED. A typical LiFePO4 AA cell for this application is rated around 500 to 600 mAh. This means a stored energy of about 1.6 to 1.9 watt-hours, 100% of which is delivered to the LED. In short, one AA LiFePO4 cell replaces two AA NiCds and also eliminates the need for additional driver circuitry.


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## cy (Nov 27, 2013)

jtr1962 said:


> I'll add that solar lighting seems to be another niche use where LiFePO4 is catching on big time. Anyone who has ever tried solar outdoor lighting has had issues due to battery failure. NiCd and NiMH just don't hold up in this type of use where they may be subject to overcharge, possible overdischarge, temperature extremes, and hundreds of cycles annually. A possible exception might be very robust cells like Eneloops but those are often too costly for this application. Moreover, the voltages of NiMH and NiCd are not well matched in this application. Boost circuits to drive the LEDs are required. Given the cost constraints, these are often quite inefficient. And the solar cells on many outdoor solar lights output ~3.6 volts. This is too high for 2 cells in series but too low for 3 cells. LiFePO4 on the other hand is a perfect match here. The 3.6 volts coming from the solar cells is perfect for charging with no possibility of overcharging. And the flat ~3.2V discharge curve is perfect to drive LEDs without any additional circuitry. Moreover, the energy density is superior to the NiCad batteries typically used in this application. Usually a pair of Nicads of about 700 mAh are used. This gives about 1.7 watt-hours but often 1/3 of this is lost in the boost circuit, delivering only 1.2 watt-hours to the LED. A typical LiFePO4 AA cell for this application is rated around 500 to 600 mAh. This means a stored energy of about 1.6 to 1.9 watt-hours, 100% of which is delivered to the LED. In short, one AA LiFePO4 cell replaces two AA NiCds and also eliminates the need for additional driver circuitry.



besides night and day differences in safety with LiFePO4 vs LiCo .. same thing could be said for number of charge/recharge cycles. provided LiFePO4 is not charged above 14.4v (14.6v 100%) and not discharged below 12.85 (20%) 2,000 to 5,000+ cycles is not unheard of. 

besides safety and long life .. LiFePO4 multiples has the HUGE advantage of naturally mating up with LOTS of existing electronics. for instance .. ALL 12v charging systems designed to support PB. which happens to include almost every car/motorcycle made within last 25+ years .. will support LiFePO4 x4 in series = 14.6v full .. but that's misleading, the very first drain, voltage will drop to 13.3v (90%) .. then stay almost flat down to 12.4v (10%) .. this voltage profile fits 12v vehicles perfect!

ALL charging systems designed to support PB will put out 13.8v to 14.2v range ..with some modern motorcycles 14.4v range. again this fits perfect with 12v LiFePO4 max charge of 14.6v.

there are millions of 12v vehicles out there .. while it's not worth trouble of changing to LiFePO4 for most cars. fact is saving 30-40lb is just not that important.. unless you are amongst micro groups like 911 owners. 

for the millions of 12v motorcycles out there .. saving 10-15lb is a very significant weight savings. speed of adoption for 12v LiFePO4 motorcycle batteries has surprised a number of battery mfgs. evidently there are LOTS of folks out there willing to spend say $225 to $300+ for a LiFePO4 battery to save 10lb to 15lb+ on their motorcycle. 

then factor as AH capacity increases .. the density to weight ratio between LiFePO4 and LiCo starts to narrow... IMHO the future belongs to LiFePO4!!

then factor inherent safety of LiFePO4 due to chemical makeup. this mean LiFePO4 tolerates minor overcharge conditions without damage. during tests to destruction, it took wild abuse of charging 39v+ to catch 12v LiFePO4 on fire. it's very_difficult to cause a LiFePO4 battery to catch on fire, but it can be done. 

most if not all documented fires from LiFePO4 failure has been traced to dead shorts internal or external from wrecks and/or bad installation. I've not been able to find a single documented instance of a 12v LiFePO4 catching on fire due to overcharge conditions. there's been all sorts of reports of 12v LiFePO4 melting from too high charge rates. from installing too small 12v LiFePO4.


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## BVH (Nov 27, 2013)

I just received 12 each of the new Nissan Leaf 2S/2P, 7.6/60 AH LiMn2o4 modules. I haven't seen any definitive answer on the number of cycles these should have over their life. Most sites indicate about 500. I'm just wondering how Nissan, a large vehicle manufacturer that touts their Leaf so much, would use a battery chemistry yielding such a low life. It hardly seems that the pack would last 5 years before a serious reduction in capacity would occur, causing them issues down the road.

I'm using mine to power my large KW Short Arc lights away from an AC source and will never even put close to 250 cycles on them so it's not a big deal to me but I'm just wondering why Nissan would do this unless they project far more cycles.


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## StorminMatt (Nov 27, 2013)

BVH said:


> I just received 12 each of the new Nissan Leaf 2S/2P, 7.6/60 AH LiMn2o4 modules. I haven't seen any definitive answer on the number of cycles these should have over their life. Most sites indicate about 500. I'm just wondering how Nissan, a large vehicle manufacturer that touts their Leaf so much, would use a battery chemistry yielding such a low life. It hardly seems that the pack would last 5 years before a serious reduction in capacity would occur, causing them issues down the road.
> 
> I'm using mine to power my large KW Short Arc lights away from an AC source and will never even put close to 250 cycles on them so it's not a big deal to me but I'm just wondering why Nissan would do this unless they project far more cycles.



Hard to say about this one. I'm not sure whether Nissan is trying to get more cycles by charging and discharging them more conservatively. Or whether they are just taking a gamble. In either case, this could mean trouble for them. They could end up losing ALOT on premature warranty repairs OR end up hurting their reputation a good deal by trying to weasel their way out of replacing batteries with lower capacity. Only time will tell. Then again, the same goes for Tesla. They're using LiCo batteries. And, as anyone with a laptop or iPhone knows, they're not made to last. ESPECIALLY when, as is the case with Tesla, they are trying to maximize capacity. I know they are said to last quite a long time (I don't remember how long they said). But let's face it. Tesla is NOT in possession of a magic wand.

One more thing. With regards to the issue of EV vs ICE, I don't see EV's being better when it come to long term reliability than conventional ICE cars, at least as long as they are powered by Li-Ion batteries (with possibly the exception of LiFePO4, but even that's a maybe). Lots of people to this day are driving around 20+ year old Hondas and Toyotas, and they're still running strong. I myself have an old Civic that just refuses to quit. It doesn't miss a beat, passes smog, and still has good get up and go. Yes, I'm pretty diligent with such things as oil changes and timing belt replacements. But still, are any of today's EVs going to be around in a similar amount of time? Yes, such things as motors and controllers can run a REALLY long time. But if replacing a battery pack is going to cost several times more than replacing a conventional engine, I don't think longevity will be better with EVs. And for better longevity, one thing is clear. We need to move away from lithium.


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## cy (Nov 30, 2013)

StorminMatt said:


> Hard to say about this one. I'm not sure whether Nissan is trying to get more cycles by charging and discharging them more conservatively. Or whether they are just taking a gamble. In either case, this could mean trouble for them. They could end up losing ALOT on premature warranty repairs OR end up hurting their reputation a good deal by trying to weasel their way out of replacing batteries with lower capacity. Only time will tell. Then again, the same goes for Tesla. They're using LiCo batteries. And, as anyone with a laptop or iPhone knows, they're not made to last. ESPECIALLY when, as is the case with Tesla, they are trying to maximize capacity. I know they are said to last quite a long time (I don't remember how long they said). But let's face it. Tesla is NOT in possession of a magic wand.
> 
> One more thing. With regards to the issue of EV vs ICE, I don't see EV's being better when it come to long term reliability than conventional ICE cars, at least as long as they are powered by Li-Ion batteries (with possibly the exception of LiFePO4, but even that's a maybe). Lots of people to this day are driving around 20+ year old Hondas and Toyotas, and they're still running strong. I myself have an old Civic that just refuses to quit. It doesn't miss a beat, passes smog, and still has good get up and go. Yes, I'm pretty diligent with such things as oil changes and timing belt replacements. But still, are any of today's EVs going to be around in a similar amount of time? Yes, such things as motors and controllers can run a REALLY long time. But if replacing a battery pack is going to cost several times more than replacing a conventional engine, I don't think longevity will be better with EVs. And for better longevity, one thing is clear. We need to move away from lithium.



gotta disagree .. LiFePo4 nicely solves the longevity factor at 5,000+ cycles .. drawback is energy density. which traditionally has been solved by numbers .. highest production cells gets the most R&D time combined with fastest time to market for competition reasons. delivering highest energy gives a competitive advantage. 

don't assume vehicle mfg want the longest life possible. planned obsolesce in automotive is alive and well. drives long term profits. classical examples is ball joints, U-joints, wheel bearings .. all used to be serviceable parts that lasted virtually forever if serviced. auto mfg have long left off grease zerts and designed wheel bearing to be non-serviceable. forcing replacing entire rotor assembly with bearings impossible to service. etc. etc.


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## KiwiMark (Dec 1, 2013)

cy said:


> two years later .. looks like your prediction of A123 going out of business has come to pass. but you missed the beginning of LiFePO4 use for 12v motorcycle batteries, which dwarfs market size for electric car batteries.
> 
> weight savings of say 30-40lb means little to most folks unless you are part of a tiny group of light weight high performance cars like 911 owners. but saving 10 to 15lb on a motorcycle is HUGE!
> 
> ...



I've put one of those LiFePO4 batteries in my bike, saves around 7 pounds and it seems to work really well with good cranking speed when starting.
My bike is 15 years old (1998 Suzuki RF900R) and is having no problems with the battery.

One thing I'd like to point out - not only is there a weight saving but also the battery is fairly high up on the bike (just under the seat) so saving weight there lowers the centre of gravity, which is a good thing.


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## cy (Dec 2, 2013)

KiwiMark said:


> I've put one of those LiFePO4 batteries in my bike, saves around 7 pounds and it seems to work really well with good cranking speed when starting.
> My bike is 15 years old (1998 Suzuki RF900R) and is having no problems with the battery.
> 
> One thing I'd like to point out - not only is there a weight saving but also the battery is fairly high up on the bike (just under the seat) so saving weight there lowers the centre of gravity, which is a good thing.



which model LiFePO4 did you install? it's always good to get feedback no matter where found. most common reason for early 12v LiFePO4 failure is installing too small AH. most LiFePO4 mfg use extremely misleading AH numbers expressed in pb/eq .. where a 18AH pb/eq is actually 5AH capacity.


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## KiwiMark (Dec 2, 2013)

cy said:


> which model LiFePO4 did you install? it's always good to get feedback no matter where found. most common reason for early 12v LiFePO4 failure is installing too small AH. most LiFePO4 mfg use extremely misleading AH numbers expressed in pb/eq .. where a 18AH pb/eq is actually 5AH capacity.



It is a LFX14A4-BS12, 14Ah equivalent.


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## cy (Dec 2, 2013)

KiwiMark said:


> It is a LFX14A4-BS12, 14Ah equivalent.



1998 Suzuki RF900R should have about a 400 watt permanent magnet charging system. Shorai LFX14A4 weight is about 2lb .. so actual AH capacity is about 5AH. 

labeling for 12v LiFePO4 has gotten so distorted that weight is one of the few metrics that's reliable to determine actual AH capacity. forget that pb/eq noise .. it means little to nothing. 

a 5AH capacity LiFePO4 battery is way too small for a 900cc motorcycle. it may start just fine during moderate condition but will really struggle when temps dip down below 32f. 

other factors to consider is max charge rate and parasitic drain. older bikes typically has lower parasitic drain rates. a tiny AH capacity doesn't last long sitting before battery is drained to dead and/or almost dead. LiFePO4 will still manage to turn over bike one time at 5% state of charge. 

after bike starts with battery at 5% ... LiFePO4 is then in bulk charge mode and will swallow all the amps thrown at it. 405 watts / 14.2v = 29 amps less system overhead = 20 amp available to charge battery. 20amp / 5AH = 4C charge rate (C = AH) .. LiFePO4 cells typically don't like being charge over 4C

so with a 405 watt charging system .. a 5AH LiFePO4 will do just fine. but with bike with larger alternators like BMW R1200 with 720 watt .. less overhead = 37 amp / 5AH = 7C charge rate .. that will get a 5AH battery hot enough to melt.


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## KiwiMark (Dec 3, 2013)

cy said:


> other factors to consider is max charge rate and parasitic drain. older bikes typically has lower parasitic drain rates.



I am sure that you are right about that, I've had the bike sit in the garage for a couple of weeks and then when I started it there was no noticeable loss of cranking speed from the starter. I have trouble thinking of anything on the bike that would drain power when it is off - it doesn't even have a clock.

My previous bike was a 2007 model Suzuki AN400 (good for city commuting) and it would have had some parasitic drain with the SACS (security system) and electronic dash with clock.


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## tlb03 (Mar 22, 2017)

Thanks to the intelligence of posters here...I'm learning.

I'm buying batteries for a solar configuration in the RV industry (say 200aH to 300aH units). This industry seems to lack understanding of battery chemistry and market trending. They all use LiFePO4 products and don't seem to understand the differences in Lithium choices. However, they are very good at installations. I'm looking at purchasing a battery from ebay that is listed as a "Lithium 12vdc 300ah 2.4kwh New 2015 VOLT battery Solar Off Grid Golf Cart". What I can't find out about this OEM product is the cycle life. The sales person doesn't know and is a tough character, funny, but a bit salty. The point is, he is not a help here. The price is less than half of the LiFePO4 products, so my interest is keen on the other product. The cathode material is listed as "LiMn2O4 with LiNiO2". I assume this is some type of Lithium Nickel Manganese product that I have read good results about. My understanding says this product is slightly less safe than the LiFePO4 product all things being equal but not "unsafe". My biggest question is trying to figure out the cycle life of this product. I can't find info anywhere and don't know how big a deal this might be to my buying choice. I'm not technically proficient here, but I do want to make a sound and wise purchase. These things are expensive!


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## Gauss163 (Mar 22, 2017)

Those packs are recycled from electric cars - the Chevy Volt in the case you mention. Search on that and you will find much more.


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## tlb03 (Mar 22, 2017)

Gauss163 said:


> Those packs are recycled from electric cars - the Chevy Volt in the case you mention. Search on that and you will find much more.



The seller states they are new direct from GM who assembles the packs that come first from LG Chem in Japan. He has a 100% ebay rating from 749 users, so I suspect he is a truth teller, although as I stated a bit salty. I will search on that because that's also an option I should look at. Thanks for the suggestion.


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## Gauss163 (Mar 22, 2017)

Be careful with eBay feedback. Even sellers of "10000mAh" 18650s receive almost all positive feedback on them. The general public is not a trustworthy source of wise reviews.


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## tlb03 (Mar 22, 2017)

Gauss163 said:


> Be careful with eBay feedback. Even sellers of "10000mAh" 18650s receive almost all positive feedback on them. The general public is not a trustworthy source of wise reviews.



Wise precaution, thank you!


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## Peter A (Dec 26, 2021)

Battery Guy said:


> jtr1962
> 
> I simply leave you with this point: if LiFePO4 were all it were cracked up to be then everyone would be using. In fact, the opposite is true. The early adopters (e.g. Black and Decker) are moving away from it, and no major US, Japanese or European car company is using or even considering using it.
> 
> ...


B&D and others moved from LiFePO4 because of cost, not performance. The 18650 market became commoditized and A123 couldn't compete even with their Chinese plant. Your prediction about A123 did come true, but that was more about betting too hard on the automotive market too early. Now all of us are spread across the industry.


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