# Rechargeable A2?



## leukos (Jul 11, 2005)

Most rechargeable Li-ions don't fit in the A2 body, but I was thinking of using 2 RCR2 with a restistor so I don't fry the LEDs. I suppose I could make a spacer to house the resistor and make up for the shorter length of the RCR2s. The problem is I don't know the amp draw of the MA02 and don't know what size resistor. I think I'll need something like 1.5 ohms and 3.5 watt if anything like that exists. Anyone have any advice? Thanks. /ubbthreads/images/graemlins/icon23.gif


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## pyro (Jul 11, 2005)

Look at the LED board, there are resistors for each LED on it.
These can be exchanged and nothing else is needed,
as the xenon beam is already regulated and will
work with the higher voltage. 
(Willie Hunt LVR)
I look for an extra LED ring some time now, to swap out the LEds wit newer ones...


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## seattlite (Jul 11, 2005)

I was hoping to use a 1xRCR123(MP brand) with a CR123 spacer to fill the tube. However, the CR123 spacer that I have(DSpeck) is a little to big to fit in the A2's battery tube. Anyone know where I might to find a smaller diameter CR123 spacer?


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## leukos (Jul 11, 2005)

seattlite,
The SF Z20 fits perfectly in the A2 (made of aluminum though instead of brass). I couldn't fit AW's MP in my A2. Also, 3.7v doesn't seem enough to power the circuitry in the A2. I hope that wasn't your only light you want to use those on. /ubbthreads/images/graemlins/icon23.gif

Pyro,
Changing the resistors on the LED ring makes a lot of sense, maybe I'll send Chop a PM. The reason I was thinking of having an extra resistor though is so that the A2 would have the same performance if I put primary cells in it.


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## Bullzeyebill (Jul 11, 2005)

I think that the voltage of the A2 lamp is 3.6 or 3.7 volts, and draw would be something like 1.5 amps, maybe less. The regulated circuit needs 6+ startup volts for good run time, and would handle the 8.4 volts of the RCR123's. If you could remove the leds or resistor them, you would be in business with 2 RCR123's.

Bill


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## seattlite (Jul 11, 2005)

[ QUOTE ]
*leukos said:*
seattlite,
The SF Z20 fits perfectly in the A2 (made of aluminum though instead of brass). I couldn't fit AW's MP in my A2. Also, 3.7v doesn't seem enough to power the circuitry in the A2. I hope that wasn't your only light you want to use those on. /ubbthreads/images/graemlins/icon23.gif


[/ QUOTE ]

Nope. I have other LED lights that need the RCR123's. The MP's also work quite nicely in a Vital Gear F2 with a P91 /ubbthreads/images/graemlins/grin.gif.


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## mahoney (Jul 12, 2005)

Just for the heck of it I tested the current draw of my A2 a couple weeks ago. It was 1.500 amps from fresh Battery Station 123 cells.

If you put the resistor in line with the rechargeable cells in the body, a couple things to think about; 1.5 amps is a lot of current, the resistor is going to get "warm" and you will be dropping the voltage to the LVR and lamp as well as to the LEDs. A bunch of resistors in parallel should be able to handle the load if you can't find just the right value in a high wattage resistor. But any extra capacity you would get from the higher voltage of the Li-ion cells will be dissipated in the resistor. This may not be an issue since the cells are cheap to recharge, but you'd get longer runtime by just adding the extra resistance to the LED circuit.

One issue that may come up though, will the existing resistance in the switch be sufficient to keep the LVR from powering the lamp in low mode given the 8.4 volts of the li-ion cells vs the 6 volts the light is designed for. If not, you would need the resistor in the body, or you'll have to increase the resistance in the switch too. Remember that the switch resistance is no longer in the circuit when the LVR/lamp is on, only the SMD resistors on the LED ring are protecting the LEDs at that point.

Hope your experiment turns out well.


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## Spacemarine (Jul 13, 2005)

@mahoney:

I think what Pyro meant was that we wants to add a resistor only to the LEDs, not to the main regulation circuit.



> *Bullzeyebill said:*The regulated circuit needs 6+ startup volts for good run time.



Why is that? I think the purpose of the regulation is to keep a constant output, especially below 6V, when you batterys are already drained!


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## mahoney (Jul 14, 2005)

The LVR in the A2 reduces the battery voltage going to the lamp. If, as suggested, the lamp is 3.7 volts, the LVR will meter out the power coming from the 6 volts of batteries so the lamp only gets 3.7 volts. When the batteries are depleted to slightly above 3.7 volts the LVR shuts off, both to protect the bulb, and allow the "LEDs only" operation mode. The LVR can probably handle a higher input voltage than 6 volts, and you can change the SMT resistors to protect the LEDs, but... 

The 2-stage switch has a resistor in it for the "LED only" mode that drops the battery voltage to a level that is below the "on" threshold for the LVR. That resistor may not be sufficient to drop the higher voltage from the Li-ion rechargables below the "on" threshold of the LVR and then the incandescent lamp would operate in both the modes. Hence the possible need for a resistor change in the switch too or a resistor spacer in the body of the light.


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## leukos (Jul 14, 2005)

Good point, Mahoney. I noticed the resistors on the LED ring are marked 33RO, does that mean .33 ohms? I'm not too familiar with the small ones.


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## mahoney (Jul 14, 2005)

It's more likely to be 33 ohms, I think the R takes the place of the decimal point, but I would suggest testing with a meter to be sure of the value. If they are 33 ohm, that means the LEDs are getting about 50-60 ma through each of them when the incandescent lamp is on, depending on how much the battery voltage drops under load.


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## leukos (Jul 15, 2005)

I think the resistor in the tailcap is 10 ohms, so I guess I'm at 43 ohms when I'm using the low mode. However, I don't think the resistor in the tailcap is engaged in the high mode (similar to McGizmo's two-stage switch), but the LEDs remain on. So I'm not sure at this point what resistor value should go in the tailcap and on the LED ring. Wouldn't my original idea of making a spacer with a resistor in it be less of a headache and more versatile?


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## mahoney (Jul 15, 2005)

Yes it might be simpler to just make the spacer, especially if you want to be able to easily go back to regular 123 cells for any reason. But at this point someone with more electrical engineering experience than I will have to step in. It occurs to me that a resistor value that will keep the LVR happy at it's fairly high current draw may not be sufficient to protect the LEDs at their more modest current draw. You still might end up needing to adjust the LED ring resistors even with a resistor in line with the battery. The A2 really was well engineered for a 6 volt power supply.


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## leukos (Jul 29, 2005)

Well, I've been using two batteryspace.com's Powerizer RCR123a 650mAh in my A2, they're the only R123s that seem to fit. They last about 30 minutes in incandescent mode before the regulation kicks out. Usually the cells are between 3-3.1v when the lamp dims. I've ran them through my A2 about 5 times now with probably about 15 hours in LED only mode. I think I'll keep testing for long term effects and update periodically. /ubbthreads/images/graemlins/cool.gif


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## seattlite (Jul 29, 2005)

[ QUOTE ]
*leukos said:*
Well, I've been using two batteryspace.com's Powerizer RCR123a 650mAh in my A2, they're the only R123s that seem to fit. They last about 30 minutes in incandescent mode before the regulation kicks out. Usually the cells are between 3-3.1v when the lamp dims. I've ran them through my A2 about 5 times now with probably about 15 hours in LED only mode. I think I'll keep testing for long term effects and update periodically. /ubbthreads/images/graemlins/cool.gif 

[/ QUOTE ]
Are the Powerizer cells 4.2V fully charged? Did you blow out the LED's running at around 8.4V?


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## leukos (Jul 29, 2005)

Well, charged to maybe 4.12. No LED failures (yet).


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## seattlite (Jul 30, 2005)

[ QUOTE ]
*leukos said:*
Well, charged to maybe 4.12. No LED failures (yet). 

[/ QUOTE ]
Hmmm....the MP's fit fine in my A2. Maybe, I'll muster up enough courage to run my A2 with 2 MP RCR123's.


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## Sean (Sep 12, 2005)

Are the Powerizer cells unprotected (bare) cells?


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## Trashman (Sep 12, 2005)

How about those 3v R123's? I've read they charge to 3.7v, and under load they drop to 3.1 or 3.2v.


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## AFAustin (Sep 13, 2005)

Here's the link to the "3.0v" 123 rechargeables:

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1641

I am likewise curious whether they could be an answer for the A2, the L4, and a lot of the other CR123 lights that can't take 3.6V R123s....?

Would appreciate any thoughts. Thanks.


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## leukos (Sep 15, 2005)

I haven't tried the 3v Powerizers, but the regular ones seem to be doing fine in my A2. I think I've cycled them well over 150+ times with no noticable dimming of the LEDs. 
The problem with so called "3v" li-ions is that they are usually regular 3.7v lions that have a cutoff circuit in them or in the charger that won't allow them to fully charge to 4.2v. That means decreased capacity (unless there is newer technology that I am unaware of).






Here's some pictures again for those who are new to the discussion:


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## AFAustin (Sep 15, 2005)

Leukos, thanks for the info. on the 3.0v rechargeables.


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## leukos (Oct 3, 2005)

Just wanted to bump this thread for those who might be interested in trying a rechargeable A2. It seems that AW's MP700 cells work as well as batteryspace.com's Powerizer RCR123a cells. I use the latter and have well over 150+ cycles on them through my A2 and I usually run them until the regulation kicks out. I'll post periodically for those who want a little more field testing before trying it on their own.


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## Bullzeyebill (Oct 3, 2005)

leukos, what is runtime till regulation cuts out, and what voltage are cells reading when reg cuts off. Have you checked current? Should be around 1.7 amps.

Bill


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## leukos (Oct 4, 2005)

Maybe someone with more electronics savy can measure what voltage the li-ions cut off at under load, but the Powerizers run about 30+ minutes in incandescent mode before regulation cuts out. They read between 2.9-3.1v on my multimeter when I take them out of my A2.


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## BrianChan (Nov 12, 2005)

Those purple rcr123s sold by lighthound sometime ago works in my A2.Used them when i got my A2 yesterday.So far no problems.I noticed the bluish LEDs when using the rechargeables.I know from reading other posts that i am overdriving the LEDs so i would like to know wether there are any differences in brightness between the rechargeables and the SF123a.I took the rechargeables out,put the SF123as back into the light and turned it on in LED mode.I noticed that the brightness of the LEDs are the same.

Can anyone please explain this to me?


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## wquiles (Nov 12, 2005)

I just wanted to add to what leukos said earlier.

I use AW's MP rechargables in my A2 (about 15 cycles so far and counting ...) and the A2 works great for about 30 minutes or so before going out of regulation.

I did, however, changed my LED's to KevinL's 35K whites (no more angry blue for me!) and I also changed the resistors from 33 ohms to something like 90 ohms or so since I wanted to make sure that my LED's would have a long life with the rechargable cells due to the significantly higher voltage.

Will


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## leukos (Nov 12, 2005)

BrianChan,

Like you, I can't notice any difference in brightness in the LEDs when switching between primaries and rechargeables. As wquiles said, a little calculation lets you know that you are really overdriving these LEDs with RCR123s. I've been running mine on Li-ions for about 150+ cycles now with no problems. If you want to be safe and you have the modding skills, you might want to do as wquiles did and put in some higher resistor values. I lack the said modding skills, so mine are OEM, but maybe I should send wquiles a PM.......


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## BrianChan (Nov 12, 2005)

Hi leukos and wquiles,

Thanks for the info.I'm the same as leukos,no soldering skills to do the mod but i really wish to do so because i really like the A2 + rechargeable combo,i'll really hate it if the LEDs are fried. Wquiles,can the A2 run without the LED ring? I was wondering if you can do the mod you did to your LED ring for me?I'll pay any costs related to the mod including return postage.I'll send the ring to you,and PP you the funds.What do you think?


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## Bullzeyebill (Nov 12, 2005)

BrianChan, over in the Benchmark Light Testing thread, in the battery forum, one of the lights being passed around for testing is an A2 without the led ring. The A2 is courtesy of PK of Surefire. So, yes the A2 can run without the led ring.

Bill


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## wquiles (Nov 12, 2005)

Another data point on the A2: Even if the bulb is dead, you still need to leave it in place for the LED's to lit at all - I know first hand since during some experiements I killed my A2 bulb and tried to run the LED's without it 

EDIT: Comment above seems to only apply to my own A2 as several others have tried and their A2's work fine with no bulb in place.


As to modifying A2's for the resistor/LED swap, I might consider doing this for others in the future, but I currently have no time for doing my own projects . Here is the original thread by AuroraLite that showed me how to do the change:
Dummy reference guide to SF A2 modding with MJ led (or 35k 5mm) leds  

Will


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## pyro (Nov 12, 2005)

wquiles said:


> Another data point on the A2: Even if the bulb is dead, you still need to leave it in place for the LED's to lit at all - I know first hand since during some experiements I killed my A2 bulb and tried to run the LED's without it



Now that is strange, both of my A2 run without the bulb inserted!
I had to tighten the bezel a little more as usual, but it worked.

On the other hand, why do you want to remove the dead bulb without having a new one to swap?


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## wquiles (Nov 12, 2005)

pyro said:


> Now that is strange, both of my A2 run without the bulb inserted!
> I had to tighten the bezel a little more as usual, but it worked.



I tried it once again and my A2 will not fire its LED's without the bulb in place. Maybe a tolerance issue with my unit?




pyro said:


> On the other hand, why do you want to remove the dead bulb without having a new one to swap?



It took my a week to get a replacement A2 bulb, so in the meantime I tried it and found it would not lit. I put the dead A2 bulb back and the LED's worked again 

Will


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## SilverFox (Nov 12, 2005)

Hello Will,

I just took the lamp out of my A2 and the LED's came on without any problems...

Tom


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## wquiles (Nov 13, 2005)

I tried it again just now and the LED's don't come ON without a bulb. Must be a slight tolerance problem in my particular unit 

No worries on my side since even if it dies, I will simply leave the dead bulb in place while I put in a replacement.

Good to know that most other A2's work fine without the bulb in place 

Will


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## BrianChan (Nov 18, 2005)

For those people that couldn't fit the MP700s into their A2s,i have a solution.

Peel off the wrapper of the battery and try putting the cell into the A2. If it fits,re wrap it using tape.Any thin wide cellophane tape will do.Take out the black disc covering the positive terminal and start wrapping. Make sure you wrap so that the tape covers every part of the battery walls as the whole 'can' is the negative terminal! So make sure the sides are not exposed. Another thing is you have to cut just the right amount of length of tape to wrap the battery as the overlapping tape will increase the diameter on that particular part of the battery,and may get stuck when you try to put it into the A2 afterwards. Lastly, replace the small black disc on top of the battery and you're set.

My MPs fit nicely after rewrapping them so i hope your MPs will too!


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## BrianChan (Nov 24, 2005)

Guys, after using the LEDs for a while with MPs each led developed a different tint.One remained white,one developed a warm, slightly yellowish tint and one had a green tint! I thought of changing the LEDs so I've opened up the head and took the LED ring out to have a look and i discovered that the soldering is way beyond my skill to change those LEDs.Anyone had their LEDs' tints change before?


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## wquiles (Nov 24, 2005)

Brian,

I don't have experience on a tint change, but given that I found (link) that the MP700's really overdrive the LED's, I am not surpriced to hear this strange behavior change. If you can, I would investigate putting new LED's AND also increasing the resistor values to something in the 90-110 ohm range.

Will


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## BrianChan (Nov 25, 2005)

wquiles,

I really wanted to change thoes LEDs but i simply don't have the kind of skill or confidence in doing it myself.I'm worried that i might really ruin the ring if i do it.Can anyone help me change the LEDs? The tint appeared after just 1 hour of reading in the dark.Should i remove the ring now to avoid further tint change until i have sucessfully changed the LEDs?


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## wquiles (Nov 25, 2005)

Since the LED's are already changing tint, just leave them there. They might get worst or simply die, but since you are going to eventually change them, I would not worry too much about it.

Try to find somebody local to help you with the swap. Maybe somebody at an electronics/computer repair shop might be able to do the swap for a small fee.

Will


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## leukos (Nov 25, 2005)

BrianChan,
Sorry to hear about the tint shift in your LEDs. Were you running them in LED mode right off the charger? I usually hit the high mode for a few seconds to take the edge off of freshly charged cells. I have green LEDs though, I'm sure color shift is more obvious with white.


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## BrianChan (Nov 26, 2005)

Guess I'll just leave them in the light until it dies.Yes i run them right off the charger a few times.Maybe that's why the tint changes due to the high current.The tint pretty much stays the same now.It's not that bad,i'll have to look into the LEDs to notice the tint.For shining on the pages of a book it's still perfectly fine for reading.

Guess i'm the first person in CPF with an A2's LED change tint.


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## leukos (Nov 27, 2005)

I sanded my white LEDs to get rid of the angry blue in the beam. It takes away a little of the throw, but it makes such a smooth diffused beam. I've done it to my red and green A2s especially to get rid of the ringy beam. Maybe that would help a little with the color shift?


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## BrianChan (Nov 27, 2005)

Leukos,

Thanks for the tip! I'll try it out tonight.The tint might not be so obvious anymore.


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## Arkayne (Nov 28, 2005)

BrianChan said:


> Hi leukos and wquiles,
> 
> Thanks for the info.I'm the same as leukos,no soldering skills to do the mod but i really wish to do so because i really like the A2 + rechargeable combo,i'll really hate it if the LEDs are fried. Wquiles,can the A2 run without the LED ring? I was wondering if you can do the mod you did to your LED ring for me?I'll pay any costs related to the mod including return postage.I'll send the ring to you,and PP you the funds.What do you think?



Howdy! I'm just joining the Surefire bandwagon and had to chime in with pics of the A2 working w/o the led ring. I'll be doing the rechargables soon so I'll be sure to present a pictorial how-to for putting on the ~90ohm resistors on the led ring.


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## 78CJ5 (Dec 24, 2005)

Luekos,

PM sent.


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## Bullzeyebill (Jul 9, 2006)

Bumping this thread as I have a question about running RCR123's, I use Powerizer 3.7-4.2 volt batteries. My A2 has red leds in ring, and each resister is marked 1000. Is it ok to run these with RCR123's. 

Also, I noticed when I took out leds that the circuit was open when I did not turn tailcap switch all the way out to lockout. I measured voltage and got a reading from front of circuit. I got no voltage reading when I turned the switch out to lock out position, or close approximation to lock out position, I found this out when I noticed that my batteries were being depleated just sitting there, main light off, but switch just turned so that main light was off. I took reading of my batteries overtime and sure enough they were being depleated. They were not being drawn down when I turned switch to lockout position. I think this condition is sort of what mahoney was talking about earlier in this thread. The resistor in the tailcap is not matched to the voltage output of the LiIon's. 

Bill


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## leukos (Jul 9, 2006)

Bullzeyebill,

If you use Li-ions in your A2 unmodified, you will overdrive your LEDs. As far as it being ok, that may need to be qualified. BrianChan had a vf shift with his white LEDs. TMK, no one using Li-ions has reported a failure. I have hundreds of hours using Li-ions with my green A2, unmodded and no problems (just a burned out lamp after 60 hrs). The best option is to put higher resistor values on the LED ring so as to not damage the LEDs. 

As to your question about batteries being depleted, I have not tried your particular experiment, but I imagine with the LEDs removed and the tailcap set in low mode that the batteries are sending current through the circuitry and the 10ohm resistor and slowly draining the batteries through heat dissipation. The easiest solution seems to back the tailcap out to the lock-out position when not in use.


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## Bullzeyebill (Jul 9, 2006)

leukos, thanks for reply. What does 1000 on each resistor mean? anyone know? I am not concerned about current drain, I just thought it was interesting to know.

Bill


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## Energie (Nov 9, 2008)

I´ve a newer A2 (rounded body). 
AWs RCR123 (label removed) fit after a bit sanding at the end of the battery tube.

The resistor in the tailcap has 10 Ohm.
Each led has its own 33 Ohm resistor.

Current to each led with *2*3V* CR123 batteries is 40 mA (-->bit too much).
Power to the led-resistor is 53 mW (-->ok).

Current to each led with *2*4,1V* RCR rechargeables is 70 mA (-->too much) 
Power to the led-resitor is 162 mW (-->bit too much).

So I´ve changed the stock leds to THC-leds, which can handle the higher current. You can also use a 5 mm 0,5 watt type.

Works flawless so far.


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## mitch79 (Nov 10, 2008)

Energie, where did you get the THC-led's from? I've been looking for a while and can't find them anywhere.
Those 0.5W led's from led-tech.de look interesting too.

My A2 is modded with Nichia NSPL-500S warm white LED's and 100 Ohm 0805 SMD resistors in the LED ring. These replace the stock 33 Ohm resistors.

Current draw with AW's RCR123's and the 10 Ohm tailcap resister in series;

Fully charged, 4.16V per cell;
116mA. Or *38.67mA* per LED.

Fully discharged, 3.5~3.6V per cell;
84mA, or *28mA* per LED.

Runtime analysis;

```
SF MA02         AW protected RCR-123:   32min 26sec
LF HO-A2        AW protected RCR-123:   29min 20sec
SF MA02              Soshine RCR-123:   41min 23sec
LF HO-A2             Soshine RCR-123:   36min 20sec
FM Strion Socket Kit Soshine RCR-123:   31min 55sec
```
The AW protected cells cut out at ~3.5V, the Soshine unprotected cells cut out at ~3.0V and quickly bounce back to ~3.3V after a few minutes.
My AW cells fit in my round A2 with the labels removed but don't fit in my 4 flats A2.
The Soshine cells drop into both A2's perfectly.


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## Energie (Nov 10, 2008)

I´ve got the THC Leds from this shop (closed): Link
The 0,5 Watt led from led-tech.de is brighter than the THC led.

Your 100 Ohm resistor is perfect with RCR 123.
I´ve left the 33 Ohm resistors in the A2 because sometimes I use CR123 batteries.

Thanks for the runtimes. :thumbsup:


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## Gunnerboy (Nov 10, 2008)

FYI, *lsdiodes.com* only had single-die THC3's left for sale, no four-die.

You can still send email to [email protected] and ask if they still have any left.

Cheers,
Gary


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## Chrontius (Nov 12, 2008)

I'd suggest one of Koala's onion rings - these are regulated PCBs for the Aviator that take any bi-pin LED without soldering and substitutes entirely for the stock LED ring. Modification is completely reversible, and IMHO, this should be how the light came from Surefire. 

I'll hopefully get one for Christmas, along with some Nichia GS, snow LEDs, and high-CRI 5mm diodes to play with. ^_^


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## mitch79 (Nov 13, 2008)

Couldn't agree more with the onion rings, but I got tired of waiting so 100 Ohm resisters it is for now.


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## Bolek (Mar 20, 2011)

I just got my A2 LED blue. Only one of my 17670 fit (and I need this one for my L2). Works great with one rechargable and with 2 123. Is 2 RCR 123 safe for a A2 LED (the central light source is a white LED)?


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