LiFePO4 and IMR

jso902

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Hi physics guru's or battery guru's,

Why would a person pick IMR over LiFePO4?
It appears a lot of LiFePO4 can ban be discharged at a high rate.
Is it strictly capacity improvement and a higher voltage?

Thanks in advanced
 

RetroTechie

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Is it strictly capacity improvement and a higher voltage?
Mostly, yes. But I'll add one more: it's easier to find quality / respected brand IMR cells (like AW's), than it is for LiFePO4​.

LiFePO4​ is a nice tech on paper. And it's without a doubt the best choice for some applications. But actual products out there are often lacking in one way or another. More so in the case of small cells like 16340 or 14500. :(
 

jso902

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i noticed certain chemistry types are harder to find in your more difficult to find cell sizes. Thanks for the thoughts!
 

snakyjake

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Mostly, yes. But I'll add one more: it's easier to find quality / respected brand IMR cells (like AW's), than it is for LiFePO4​.

I haven't found it difficult to find LiFePO4 (LFP) from Surefire at $6 each. Or go to K2's website and order.
 

jso902

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I haven't found it difficult to find LiFePO4 (LFP) from Surefire at $6 each. Or go to K2's website and order.

oops; i was referring that comment towards the less common sizes like: 17500/ 17670;/ 18500
 

StorminMatt

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Although IMR has LOTS of downsides compared to LiFePO4, the reason that it is preferred around here is that it's a drop-in replacement for ICR. Flashlights are generally designed around 3.7V chemistry rather than 3.2V chemistry. Because of this, IMR is preferred to IFR, despite all the advantages of IFR.

Of course, what we REALLY need is a better 3.7V battery, with all the advantages of LiFePO4 (like safety, constant voltage discharge, long life, etc) and good capacity. But whether improvements in current 3.7V chemistries can bring this about or whether new chemistries with these advantages can be found is another matter.
 
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