# LiFePO4 and the A2 Aviator?



## KevinL (Nov 7, 2007)

Hey guys (and gals) - aren't the new LiFePO4 cells perfect for the Surefire A2 Aviator? They are a nominal ~3V per cell, rising to ~3.3V at full charge, in addition to being an inherently-safe chemistry. Negligible risk of overdriving the light, at a slight loss in capacity.. still good though?


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## Daniel_sk (Nov 7, 2007)

You can use rechargeables, the lamp has it's own regulator (PWM) and it will supply always the same voltage to the lamp. The inner tube is quite narrow, some rechargeable cells fit and some don't. 
Only the LED's are direct-drive, and will be slightly over-driven if you use rechargeable batteries. One solution is (or was?) the Aviatrix ring, Aviatrix LED's are ready for rechargeables. 
There is more information on this, check out the link in my sig, it's an index of threads about A2 (some of them are about rechargeable options for the A2).


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## DanielG (Nov 7, 2007)

The only one I know for sure is AW 18650 will not fit. I tried last night.


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## Illum (Nov 7, 2007)

neither does AW 17670s in both the old and new A2s....and no skinning them doesnot fit either

I think one of the major limitations of the A2 almost includes the fact its a CR123a ONLY LIGHT with no modding possibility [at least for the old square body ones] as theres a thread somewhere regarding someone boring out a C2 and nearly bore through...I dont know about the new A2.

as much as I like the A2, I stopped using it all the time and started using a minimag [auroralite 2x14500s] because I can't support the battery use.
If the A2 has the regulator built into a removeable head, Im pretty sure the honorary machinists [like leef] on the forum would've made a body for it already


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## leukos (Nov 7, 2007)

Kevin, I don't know if I have read of anyone reporting how those cells work or fit in the A2. I would be interested to hear.


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## Daniel_sk (Nov 7, 2007)

AW Li-ion (750mah) protected RCR123 will fit, but not all cells - you would have to buy a few of them and then try to find two of them that will fit. You would get about 1/2 runtime of primary lithium batteries.


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## DM51 (Nov 7, 2007)

I haven't seen any reports of this either. The problem, if there is one, is likely to be the cell diameter. 

Most R123s don't fit into an A2 tube, and most people don't try it because of the danger of blowing the LED circuitry or the LEDs themselves. The incan LA is not a problem because it is regulated, but the LEDs are not. 

js uses a particular brand of R123 in his A2 with success, but I do not remember what brand this is. His commendably brief and succinct mini-review of the A2 may make mention of it. 

The LiFePO4, if it will physically fit inside the tube, may be a very good idea.


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## Illum (Nov 7, 2007)

unlike the L4, E2_, etc, which the body can be isolated from the head and tailcap if necessary...

with the L4, if your battery gets stuck, just stick a ramrod through the other hole and push [dunno but I think the figurative languages getting really dirty here but you know what im talkiing about]...now with the A2 if a cell should expand and get stuck in the body....theres no possibility of getting it out, while drilling is not an option sending it to surefire they may void the warranty because its well...user error

some reason an AW 17670 felt ususually snug in my L4 after a full one hour runtime and had to use a pencil to get it out by pushing from the TC.
If your going to try rechargeables....make sure the cell SLIDES EASILY when you load it in :candle:


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## who (Nov 7, 2007)

I have several 3.0V and 3.6V RCR123's from Lighthound. They all fit in my square and round body A2. I just picked a few that slide in easiest and use them. So far so good.
A2 is my #1 light, even better than the Titans that I've just received.:thumbsup:


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## Codeman (Nov 7, 2007)

DM51 said:


> ...The LiFePO4, if it will physically fit inside the tube, may be a very good idea.



I agree. If they fit, they would certainly be more friendly to the stock LED's than 3.6V LiIon cells.


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## js (Nov 7, 2007)

DM51,

I don't use R123's with my stock A2. I have a red LED-only ring and an Aviatrix ring from Bawko, and I use Powerizer Industrial (non-protected) R123's in that case, and they fit great. Those or the Lighthound R123's are the best performing R123's, but both are unprotected.

However, KevinL is talking about using an entirely different chemistry. Similar to the A123 systems cells, I suspect. (Google A123 systems for more info).

The chemsitry is inherently safe and has very high current handling abilities, and a plateau voltage of 3.3 volts, BUT, it also has a significantly lower energy density (capacity) per volume.

Plus, I wasn't aware that there were any 123 sized rechargeables except for the conventional Li-ion cells, with or without protection or 3.0 volts regulation circuitry.

Is there a LiFePO4 R123 cell? If so, Kevin, PLEASE post a link.


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## DM51 (Nov 7, 2007)

Sorry, js - my mistake - I remember you mentioning the Powerizer R123s but I thought it was in connection with a stock A2.

These are the R123-size LiFePO4s by AW - they have been available for a while now.


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## KevinL (Nov 7, 2007)

js said:


> DM51,
> 
> I don't use R123's with my stock A2. I have a red LED-only ring and an Aviatrix ring from Bawko, and I use Powerizer Industrial (non-protected) R123's in that case, and they fit great. Those or the Lighthound R123's are the best performing R123's, but both are unprotected.
> 
> ...



Yes, exactly  most people are getting confused with the regulated R123s. 

AW has been selling them for a while, 500mA per cell with capacities expected to increase in the near future. Sure the capacity isn't fantastic, but it will do. Think he has a thread in the marketplace. 

http://www.cpfmarketplace.com/mp/showthread.php?t=125353


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## AvroArrow (Nov 7, 2007)

I can help with this one. I've got 3 of those AW LiFePO4 R123s that I tried in my newer round bodied A2 Aviator. They won't physically fit. All 3 of my LiFePO4 cells measure about 0.660" +/- 0.002". I have 3 or 4 noname unprotected 3.6V R123s that I bought a couple years ago and they physically fit, but I don't use those since they'll probably burn out the white LEDs in my A2. So far the A2 is my only Surefire that runs exclusively on primary 123s. 

BTW, those LiFePO4 cells come off the charger at ~3.6V and then settle down to 3.3V nominal after a couple hours, NOT 3.0V nominal. So even if you could jam them in (by boring out the A2's tube), you'd still be overdriving the LEDs (as mentioned previously the incan is regulated so it doesn't matter for the incan lamp).

Here are some measurements I took with a dial caliper:


SF A2 inner diameter: 0.656"

Diameter
=======
LiFePO4 R123: 0.660"
unprotected R123: 0.650"
SF 123: 0.650"


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## js (Nov 7, 2007)

AW said:


> bigr said:
> 
> 
> > Will 2 of these work in a SF A2? Will a Shulze isl 6-330d-RS work for charging them? thanks Richard
> ...



So that's two sources saying these cells are too big to fit in A2. Too bad!

As for the extra voltage and the LED's, I doubt it would be a problem. A lot of people will run R123's in the A2 and their LED's often survive, although in some cases they don't. And that's 4.1 volts starting. So if they could fit, that'd be way cool!


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## KevinL (Nov 7, 2007)

Oh well. I like my black A2 but it's more of a collector's light than a worklight for me. (then again, so are most of the E1e/E2e exotic-finish lights in my collection) Worklights gotta be rechargeable. 

Thanks for filling me in on the details before I purchased a couple of the cells and found they wouldn't fit!


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## Valolammas (Nov 8, 2007)

AvroArrow said:


> SF A2 inner diameter: 0.656"
> 
> Diameter
> =======
> ...



Thanks! I've had my eye on those LiFePO4 cells, but I was worried that they wouldn't fit. Now I know they won't. I measured my A2's inner diameter and got 16.65mm = 0.656", like you said. (It seems to be a little wider further down the barrel, but I don't think I'm going to bore it out. Not this light.)

I've had even a Surefire primary get stuck inside the A2 once. I had to really give light a good shaking and swinging to get that cell to peek out enough to get a grip on the end. I wish Surefire didn't make those battery tubes quite so tight.


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## AvroArrow (Nov 8, 2007)

Valolammas said:


> Thanks! I've had my eye on those LiFePO4 cells, but I was worried that they wouldn't fit. Now I know they won't. I measured my A2's inner diameter and got 16.65mm = 0.656", like you said. (It seems to be a little wider further down the barrel, but I don't think I'm going to bore it out. Not this light.)
> 
> I've had even a Surefire primary get stuck inside the A2 once. I had to really give light a good shaking and swinging to get that cell to peek out enough to get a grip on the end. I wish Surefire didn't make those battery tubes quite so tight.



I also wanted those LiFePO4s to work, but alas... You're right, the first half inch or so of the battery tube (from the tailcap side) is a bit narrower than the rest of it, it looks almost like a ring of some sort, but it's 1 piece so... I don't know. It looks like if you were to bore it out just that first bit then the LiFePO4s would fit fine. 

Wow... you even had a SF123 get kinda stuck? Now that's getting a bit too narrow.


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## Valolammas (Nov 9, 2007)

AvroArrow said:


> Wow... you even had a SF123 get kinda stuck? Now that's getting a bit too narrow.



Yeah, as it happens I think I still have that cell. After the A2 is done with them, they still have some juice left, so I put them into my Fenix P1 for a while (the P1 gets pretty intermittent use, so they last surprisingly long in it).

Anyway, I found it and it measures just a hair over 16.6mm (0.655") at the widest point, which is near the top where the cell wrapping overlaps. The rest of the cell is narrower, it's just the wrapping overlap that sticks out. So that explains it.


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## Rossymeister (Jun 20, 2008)

I have found AW LiFePO4`s to fit perfect in the A2 Aviator. I have been using them for about a week now with no problems. Has Anyone else had good luck with them?

-Aaron


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## ampdude (Jun 20, 2008)

What is your runtime like? I figure with the regular RCR's at 1.25Amp draw the runtime is likely about 25 minutes at best. The LiFeP04's are only supposed to have about half the capacity of regular RCR's right?


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## Rossymeister (Jun 21, 2008)

I have not ran them all the way down yet. They are rated at 500 mAh,so i dont expect an excellent runtime with them. Here are a few pictures:


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