# Surefire LFP 123A lithium-phosphate rechargeable batteries



## Adam2670 (Apr 24, 2012)

Whats the deal?

Sorry for noob question but the subtle nuances of the whole battery thing is more than I'd like to do PhD type research into, I figured I'd take the lazy way out and ask you gentlemen.

I currently have about a dozen or so CR123a lights and would LOVE it if I could start using rechargeables, my first non surefire light is the Nitecore TM-11 with which I bought 4 panasonic 18650's and am very happy to have them. I would love to get rechargeables for all of my lights now and have been looking at getting some more 18650's and also some 16340's or (rcr123a's). My questions are I've noticed they all seem to have varying voltages/Wh's etc., are they at least semi-interchangeable? For instance could I put 1 18650 in say a surefire L2 instead of 2 CR123a's? or 2 16340's instead?

Are there any charts or comparisons that I could reference so I know which batteries are best to stock up on, which ones I COULD use, which ones could potentially do harm to my lights? etc, etc, etc???

thanks so much!
-Adam

Ps, feel free to blast me for my laziness and/or ignorance, as long as someone answers me


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## RedForest UK (Apr 24, 2012)

It's all in the battery section, e.g: http://www.candlepowerforums.com/vb/showthread.php?330236-2012-Battery-test-review-summary 

For what is and isn't compatible with individual lights you will have to do some quick google searching. The Surefire 3.0v rechargeables are interchangeable with their primary cr123 cells and so a safe option recommended by surefire and compatible with all their lights as a direct replacement. However, in many lights you will get more power from other chemistries/cell sizes. Remember though that most surefire lights will not fit 18650s so you would need RCR123s which if traditional 4.2v max ones may be too high voltage for some to take, or 17670s/16650s which in most will run fine, but others may be too low a voltage to maintain flat regulation.


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## Adam2670 (Apr 24, 2012)

Thanks Red, it's just all so confusing, I wish we could go back to simpler days of batteries, where basically if it fit, it worked...lol...

I was just basically wondering whether the new surefire batteries were worth buying or I could get away with just stocking up on the CR123's, I hate the idea of having 10 different battery types for 10 different lights, makes things so much more unpleasant...


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## Sgt. LED (Apr 24, 2012)

I just grabbed 50 Energizer primary 123's from battery junction for $60 plus shipping.
Rechargables are nice and all but sometimes you need to stash away primary cells just in case ...........


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## RedForest UK (Apr 24, 2012)

Ok, well as long as you don't have any single cell lights you can just get some protected 17670s (AWs are probably most consistent/reliable quality) or some 'Sanyo UR16650ZT' (search that) from intl-outdoor if you want an easier fit and slightly more capacity at the cost of protection circuitry. These should charge in an 18650 charger (I recommend the Xtar WP2 II) and can be used in the TM11. If you only have these two cell types then it really is a case of if it fits in the light you can use it safely.

If you list the lights you want to use RCRs in though I'm sure someone can give you a better recommendation.


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## Adam2670 (Apr 24, 2012)

Well up until this week I was using a either a Surefire M4 or M6 and an L2 as my primary and back-up, I have now replaced them with a Nitecore TM11 and a JETBeam RRT01 for the most part now. I was hoping I could use the new batteries for these 2 lights in my surefire gear as well, I also have just about all of the L and M series lights with some other [FONT=Arial, Helvetica, sans-serif]stragglers[/FONT]. ​


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## RedForest UK (Apr 24, 2012)

Ok, for those incan lights you are going to have to stick pretty close to the designed voltage ranges I think. Also the M6 battery carrier is designed to only allow CR123 sized cells. So I would have to recommend Surefire's recommended 'K2' energy brand LFP rechargeables for those, 3.0v LFP cells will also be safest (no heat issues) for the RRT-01 too. 18650s are the best way to go for the TM11 for maximum capacity, though the LFP RCR123s could be used in a pinch too. You could get a 17670 for a bit more capacity than 2x LFP cells in the L2 (about 5.7wh for the 17670 compared to about 3.6wh for 2x LFP cells) but it probably isn't worth the hassle, even though it could be charged in the 18650 charger which I assume you have already.

Basically, to keep it simple just get some of surefires recommended (or other brand if you wanted to save a few $) LFP (LiFePo4) cells like you were planning to originally. Stick with 18650s for the TM11 and maybe consider 17670s for the L2 and any other 2 cell LED surefires you may have, but 2x LFP cells are fine for these too if you don't think it's worth the hassle.

For reference here are some estimated wh values for what you have and may consider.

Panasonic 3100 18650: 11.2
Surefire Primary CR123: 4.4
Surefire/K2 LFP RCR123: 1.8
AW 17670: 5.7

You see Li-ion (non-LFP) have in general higher capacity with the 18650 format being the most efficient size to power ratio out there due to the massive amount of R&D put into that size's development. This makes 18650s by far the best choice for the TM11 with such high current draw. For your other lights however most will need an equivalent to the original primaries they were designed for, apart from 2 cell LED ones which can be replaced with 4.2v max li-ions in most cases as the LED vf is below the working voltage of a li-ion anyway (but only with ones that will fit in the tube!).


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## Raptor Factor (Jun 18, 2012)

What's up with Surefire selling Chinese rechargable batteries when they say to only use US batteries?


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## FPSRelic (Jun 19, 2012)

Raptor Factor said:


> What's up with Surefire selling Chinese rechargable batteries when they say to only use US batteries?



Not sure if they're Chinese, but they're just filling a customer need. The world's worst kept secret is that Surefire's regulated lights will happily work with rechargable batteries. Surefire jsut hasn't supported them until now. Considering the amount of variances in size, voltages, and chemistry safety that's out there, I don't blame them. By choosing one brand using a safer chemistry, they can now give users a choice of rechargables without having to support the wide variations out there. 

To Adam2670: according to Surefire's web page on the K2 batteries here:

http://www.surefire.com/2-pack-lfp123-rechargeable-batteries.html

The use of K2 LFP 123A's is restricted to their LED illumination products:



> *Rechargeable LFP 123A batteries are only to be used to power LED illumination
> products (built to use 123A lithium batteries) and NOT those featuring
> incandescent lamps. *The initial elevated voltage of these rechargeable
> batteries, immediately after charging, may cause the filament contained within
> an incandescent lamp to break or “burn out."



That pretty much means your M4 and M6 are not supported by Surefire to use these batteries.


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## Raptor Factor (Jun 19, 2012)

[h=5]Where are these rechargeable LFP 123A batteries manufactured? - They are made to our specifications in China. http://www.surefire.com/faqs#rechargeable[/h]I guess it's not that big of a deal but you would have really thought Surefire would have gone american when they _finally came out with some rechargable 123's. Are there even any american made rechargeable 123's?_


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## tonywalker23 (Jun 19, 2012)

I just with Surefire had them in stock! I called them yesterday and they said it would be about another month. Called every authorized dealer in driving distance and they act like they don't know what I'm talking about.


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## FPSRelic (Jun 20, 2012)

tonywalker23 said:


> I just with Surefire had them in stock! I called them yesterday and they said it would be about another month. Called every authorized dealer in driving distance and they act like they don't know what I'm talking about.



I had the same thing with distributors here. They told me that it wasn't a surefire product as such, and that they weren't being imported into the country yet. They then tried to sell me a Panasonic 18650 battery as an alternative. 

I wonder if they would have warrantied the lx2 I bought from them if I tried to install the 18650 into it.


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## doctordun (Dec 4, 2012)

Anywhere to get these other than K2 or Surefire? 
They are $6 each in both places and I was hoping for a better price..
I don't want another brand since Surefire has OK'd these for use in their flashlights and I don't want to risk the lifetime warranty.

Also, it say's they are good for 2000 cycles. Is that realistic?


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## awyeah (Dec 12, 2012)

Has anyone used AW's LFP123A batteries in Surefire lights?


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## abnjeffy (Apr 10, 2013)

I'm also interested in finding out if there is a rechargeable 123 type battery that outperforms the SF LFP123. I have an X300Ultra that runs two 123's side by side in series. I can't get anything else in there so want the best rechargeable 123 type possible, just not sure if SF's battery is it or if there is another that would be better.


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## Vox Clamatis in Deserto (Apr 10, 2013)

I tried to find the SF LiFePO4's in stock but couldn't and stumbled across some Tenergy LiFePO4's at Amazon for a very good price with the charger. For the past couple of months they have worked well in the SF lights that wouldn't take AW RCR123's or in some cases an AW 17670.

However, like everyone else I would like to avoid carrying another charger.

I am curious if the Tenergy's are the same Chinese cell as the SF LFP's.



Adam2670 said:


> Sorry for noob question but the subtle nuances of the whole battery thing is more than I'd like to do PhD type research into, I figured I'd take the lazy way out and ask you gentlemen.



There are indeed some very learned dissertations in the 'Flashlight Electronics-Batteries Included' section of CPF.


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## write2dgray (Apr 28, 2013)

No, they're not. K2 (Surefire's manufacturer for these) makes pretty high quality stuff.


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## Vox Clamatis in Deserto (Apr 28, 2013)

write2dgray said:


> No, they're not. K2 (Surefire's manufacturer for these) makes pretty high quality stuff.



How do the K2 and Tenergy cells differ? Or, are you just assuming K2 would use a different Chinese cell since they make 'pretty high quality stuff'?

So far I've had good luck with the Tenergy LiFePO4's.


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## Robin24k (Apr 28, 2013)

Tenergy LiFePO4 123A's claim "750mAh" and have minimum capacity 450mAh, but K2 Energy LFP123A's are 600mAh with minimum capacity 550mAh. Even if they do come from the same manufacturer, the cells aren't made to the same specifications.

I've never heard of K2 Energy before SureFire came out with the rechargeable kit, so I had looked into Tenergy LiFePO4 123A's. Based on the number of complaints about dead cells and reliability issues, I decided not to take the chance.


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## Vox Clamatis in Deserto (Apr 28, 2013)

Robin24k said:


> Tenergy LiFePO4 123A's claim "750mAh" and have minimum capacity 450mAh, but K2 Energy LFP123A's are 600mAh with minimum capacity 550mAh. Even if they do come from the same manufacturer, the cells aren't made to the same specifications.



Not sure I would base that comparison solely on spec sheets posted by the marketing department from what we have seen of other product claims for flashlights and batteries. :devil:

Hopefully someone will get both batteries and test and take a close look at the construction under the label.

But, I hope you are right and the K2's are worth the extra money and we are not paying extra only for the K2/SF name.

Tenergy's brand has been in the public eye recently in an unfortunate product application :

http://www.newsmax.com/TheWire/battery-boston-marathon-bombing-tenergy/2013/04/18/id/500153


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## snakyjake (Apr 29, 2013)

I purchased K2/Surefire because of Surefire's backing and K2's extensive testing. Most of all, K2's customer service has been extremely responsive of my concerns and providing me data.


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## sidecross (Apr 29, 2013)

Robin24k said:


> Tenergy LiFePO4 123A's claim "750mAh" and have minimum capacity 450mAh, but K2 Energy LFP123A's are 600mAh with minimum capacity 550mAh. Even if they do come from the same manufacturer, the cells aren't made to the same specifications.
> 
> I've never heard of K2 Energy before SureFire came out with the rechargeable kit, so I had looked into Tenergy LiFePO4 123A's. Based on the number of complaints about dead cells and reliability issues, I decided not to take the chance.



It is my understanding that the standard Surefire 123C is about 1300mAh while the Tenergy LiFePO4 is 750mAh.

I have just tried the Tenergy batteries and they have worked, but I would rather use the higher capacity Surefire’s.


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## Robin24k (Apr 29, 2013)

sidecross said:


> It is my understanding that the standard Surefire 123C is about 1300mAh while the Tenergy LiFePO4 is 750mAh.


With current technology, it's simply not possible for the 750mAh to be an accurate claim. Printing 750mAh on the batteries is pretty shady because according to the datasheet, they are only 450mAh...


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## sidecross (Apr 29, 2013)

Robin24k said:


> With current technology, it's simply not possible for the 750mAh to be an accurate claim. Printing 750mAh on the batteries is pretty shady because according to the datasheet, they are only 450mAh...



Thank you for the update on the claimed 750mAh information.


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## write2dgray (May 4, 2013)

I've tested both companies cells for 5+ years. K2 is a reputable manufacturer. Tenergy rebrands different factories' cells for different product lines.


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## Viking (May 5, 2013)

I saw a graph in another thread between K2 , Tenergy and AW's LFP batteries. Unfortunately I can't remember which thread :-(


But according to the graph, there were indeed more mah in the K2 cells , than the other two brands. 
I think it was about 30 pct or so.


AW and tenergy was almost identical , with a very slight advantage for AW.


But remember also the K2 batteries costs twice as much as the tenergy's ( $ 6,- vs. $ 3,- each ).


I would recommend tenergy over K2. Because I don't think their performance justify the big price difference. unless little more mah is very important for some specific reasons.


The batteries cycle life was not part of the comparison however.


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## N8N (Oct 10, 2013)

I looked up the datasheet for the K2 123A cell, and it says the max charging voltage cutoff of the cells is 4.2V not 3.6-3.7 as I would expect.

Has anyone tested the K2/Surefire charger and can you tell me at what voltage it terminates?

I'm seriously considering picking up a few of these cells in an attempt to get better UV performance out of my Streamlight Night Com UV relative to a single 17670, but I have this nasty habit of OCD style researching every purchase in an effort to get the highest quality/best value products.


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## Robin24k (Oct 10, 2013)

From memory, I recall that the K2 charger cutoff at 3.65V. Lithium-phosphate can be charged to 4.2V, but it will reduce cell life.


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## snakyjake (Oct 10, 2013)

N8N said:


> I looked up the datasheet for the K2 123A cell, and it says the max charging voltage cutoff of the cells is 4.2V not 3.6-3.7 as I would expect.



4.2v is the max. 3.65v is the recommended cutoff.


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## N8N (Oct 10, 2013)

Well, I just gave up and ordered... no local SF dealers have them to look at and I couldn't find a less expensive web source of the K2 cells, so I just ordered the kit off SF's web site. Will give my thoughts when I get them, although I don't really have a good method of checking capacity (no hobby charger at this time)


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## jkingrph (Feb 6, 2014)

Why are CR123a rechargeable batteries not recommended for Surefire flashlights, on the LFP 232a types.?


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## Robin24k (Feb 6, 2014)

Most rechargeable 123A's are lithium-ion, which are 3.7V and may be too high for some lights.


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## snakyjake (Feb 6, 2014)

My guess:
Lithium cobalt is dangerous. There's a protection circuit that can be damaged. The protection circuit cuts off the light when voltage is low.

I've been using K2/Surefire LFP for a year now, and I get plenty of runtime. I also like that the light doesn't cutoff on me. And the chemistry is completely safe from overcharging/discharging.

In my real use, LFP's advantages are way more than what LCO gives. I won't compromise safety.


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## GoVegan (Apr 5, 2015)

Did anyone else notice that SureFire stopped selling the K2 LFP 123A rechargeable batteries recently, they no longer appear in the "Parts and Accessories" links below each LED flashlight, in fact even the following URL no longer works:

http://www.surefire.com/2-pack-lfp123-rechargeable-batteries.html

My understanding was that they were popular, so does anyone have a definitive reason why, i.e. has anyone emailed Surefire?


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## Phlogiston (Apr 6, 2015)

I don't use them, so didn't pay much attention at the time, but it's been discussed on CPF here and here.


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## thospress (Apr 14, 2015)

GoVegan said:


> Did anyone else notice that SureFire stopped selling the K2 LFP 123A rechargeable batteries recently, they no longer appear in the "Parts and Accessories" links below each LED flashlight, in fact even the following URL no longer works:
> 
> http://www.surefire.com/2-pack-lfp123-rechargeable-batteries.html
> 
> My understanding was that they were popular, so does anyone have a definitive reason why, i.e. has anyone emailed Surefire?



Surefire Customer Service advises that Surefire is looking for a different manufacturer, and that the replacement rechargeable batteries would be available on the website although unsure when. My guess is that inventory supplies were erratic.


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