# Help surefire c2 or z2



## Mac Swift (Feb 28, 2007)

to me they sound like the same flashlight,yet just different design, 
the C2 Centurion or the Z2 Combatlight ? is one of them better than the other? 

anyones experience, or comments , pretty much want a surefire around 100bux,
going to use it as my everything flashlight, ive had all the "inexpensive flashlights" and they never last for me, i will be using the rogers method with my pistol, but not all the time and thats just an added bonus feature for me,

out of the c2 and z2 what would u take ?

and if you had a 100 bux what would you take if it could be anything ?

and if it had to be surefire ?

you people are the gurus, please help a noob out.


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## mdocod (Feb 28, 2007)

Personally- I'd go with the HA III version of the C2. I think it has a more refined handsome look to it. Pocket clip would be nice as well. I've had my eyes on the C2 and C3 for a long time (If I could only afford a Surefire!).. I'm always too broke.


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## Mac Swift (Feb 28, 2007)

ya i was sorta thinking that .its an expenisive light and im thinking way too much about it, i guess i want my money well spent.. is the HA III version that much better i also like the look but i know i will scratch it up in a week after i get it,(because im going to use it.) so will it hold up that much more, its another 25 bux or so just for the coating is it really worth it ?, i am also going to get the p61 high output lamp, 

can someone please explain to me where these 2 coatings would be most useful?
ive been trying to find info on the 2 coatings but havent had any luck. is it just like car paint from say a bmw to a corvette ? any info would be appreciated


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## jumpstat (Feb 28, 2007)

Welcome to CPF Mac Swift,

As per your inquiry, since its a Surefire you can't really go wrong. Between the C2 and Z2, both are outstanding design, my preference more towards the C2, since as mdocod pointed out its more handsome and comes in HAIII coating. As you progress, upgrades are available such as Led heads like KL3, KL5, KL6.

Either than SF, Inovas are pretty cool, US made and built tough, T1,T2,T3 looks and performs well and at reasonable prices. Pelicans M6 Led, M3 Led also comes to mind, excellent finish, all in one purchase and comes with holster and soe accessories as standard.....all within 100bux as you said.


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## sween1911 (Feb 28, 2007)

I have a C2 and I love it. Basically, because of the pocket clip, I'd say that the C2 is just a tiny bit more versatile. The Z2 was made from the ground up to be used in the combatlight (Surefire/Rogers) grip. The C2 can be used in the same manner, but it's a bit more finicky with the grip as the pocket clip can get in the way.

And yeah, there's no HAIII Z2. A friend of mine had the C2 with that finish and it's pretty nice.


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## RebelRAM (Feb 28, 2007)

I have the Z2. One thing I like about it over the C2 is that the grip rings are larger and a little more comfortable for me anyways. The HAIII would have been nice, but for my purposes, it really wasn't needed. I am debating now whether to upgrade my Z2 with one of the CREE drop-ins from Lighthound.


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## Strauss (Feb 28, 2007)

RebelRAM said:


> I have the Z2. One thing I like about it over the C2 is that the grip rings are larger and a little more comfortable for me anyways. The HAIII would have been nice, but for my purposes, it really wasn't needed. I am debating now whether to upgrade my Z2 with one of the CREE drop-ins from Lighthound.


 
I should be getting my C3 today. I ordered the lighthound CREE drop-in for it, and plan to run 2x17500's in it. I have quite a few powerful incan lights for use outdoors, so my plan for this light was to use the CREE drop-in, with hopes of having decent brightness paired with a good amount of runtime. I got a good deal on the C3, and I really like the body design....


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## nobody (Feb 28, 2007)

I've got and use both. Prefer the Z2 for use with weapon. It is very light and compact and the rubber grippy things create a very natural feeling with rogers or harries hold. No big deal to me but my Z2 has scratched up pretty easily with only occasional use. Prefer the C2 for the bulletproof finish but the clip interferes somewhat with a comfortable grip, it is heavier and the rubber finger grippy thing does not feel as positive as the Z2. Both are excellent (relatively) inexpensive lights.


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## jsr (Feb 28, 2007)

I had both, kept my C2 and sold my Z2. Here are the main differences between the two:

1. C2 is available in HAIII which is definitely more scratch/abrasion resistant than the TypeII anodizing of the Z2.
2. C2 has a pocket clip.
3. Z2 is thinner in the center of the body, making the rogers grip easier (gives the effect of the grip ring being larger).
4. Z2 is lighter.

I kept my C2 because I prefer the looks more, I like the HAIII finish, and the pocket clip comes in handy. I do wish it was lighter like the Z2. I find the body of the C2 more comfortable for me, but only slightly, over the Z2. As mentioned, the clip can get in the way if you're doing a fast draw of your light to use with your weapon. The C2 has thicker walls, which I know I won't ever put it in a situation where wall thickness and overall toughness of the body will make a difference (not going to have a grenade go off next to me).

For the most part, my choice of the C2 is mostly aesthetic (looks and finish). If you don't care about those, there's nothing the Z2 can't do that the C2 can. They (along with the 6P and G2) are virtually identical lights in terms of lighting performance (they all use the same lamp assemblies and parts), with some slight variations in body design (grip rings, square vs. round shape, etc.). For your purposes, a Z2 will serve you fine, unless you really want the finish to last longer, which the HAIII will definitely do. I prefer the Z2 over the 6P also.

Also consider some LAs from LumensFactory. They have some that provide the same output as a P61, but with longer runtime.
The Cree drop-ins from Lighthound, Litemania, and Wolf-Eyes are also very low-cost and bright LED options.

Edit - for other options, look at the Streamlight NF-2 which also has a grip ring that is adjustable along the length of the body. I'm a big fan of SL's tactical series (TL-2, TL-3, NF-2, Scorpion) as they're very well made and are considerably lower cost than similar SFs. The TL-2, NF-2, and Scorpion LED models are also very well made, but not as bright as competitors' offerings such as the Pelican M6 2390 and PentagonLight L2. The PentagonLight X2 is also another option that's available in TypeII and HAIII. Wolf-Eyes also offers very good xenon lights you may want to consider. They use the same size lamp assemblies as SF and, along with LumensFactory, offers very well performing, lower-priced lamp assembly options for W-E and SF.


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## Owen (Feb 28, 2007)

I like the way the C2's flat sides, and clip allow you to position the lamp filament so that the oval beams typical of SF, Wolf-Eyes, and Lumens Factory LAs are horizontal every time you use the light, without turning it.
I have 2 Z3s, and the user(other's a spare) is my most used incan. I'd probably prefer the C3, except that I likely wouldn't use a pocket clip on a 3 cell light, which I normally use a belt pouch for. Wouldn't mind a couple of flat sides on the Z3 instead of the skinnier round body, though. 
Really love the C2. I also think it's the best-looking SF around.


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## Mac Swift (Feb 28, 2007)

wow, you guys rock, that pretty much sums it up quite nicely for me, thank you all. 
i think im going to go with the c2, due to "its pretty" 
but one more question guys,,, another feature i liked was the 6p defender crenellated Strike Bezel ...... i just dont like the rest of the light.. is there anyway to get that head on say a z2 or c2 ???i know it only comes in black .but still is it possible to have that head put on, can you buy just the head? any imput i saw GG&G have a strike bezel for the c2,z2 ,but i like the design of the 6p defender better ..
any other bezels i can get, or thoughts ????

thanks again guys


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## Akubra (Feb 28, 2007)

I too, own both. 

Ive first purchased the Z2, a few years ago. Recently went ahead and got the C2, because I wanted the additional pocket clip. On top of that, I am also favoring the nice natural HA finish over the black Type 2 anodizing. 

Thats the things I like about the C2. What I dislike, is the wider, square body. 
Sure, it has an even more solid feel to it, yet the Z2 has a smaller/circular body. And that is much easier to hold using the "cigar grip", IMHO... . 

All that being said, I guess the ideal flashlight for me, would be a Z2 with a pocket clip, in HA finish. Best of both worlds.


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## mdocod (Feb 28, 2007)

> Also consider some LAs from LumensFactory. They have some that provide the same output as a P61, but with longer runtime.-JSR




LumensFactory has not untapped any zero point energy, they just use a different method of testing and rating their lamp. specifically, they use bulb lumens on fresh cells.. and as I understand they do have a photometric sphere to test this, so the numbers are in fact accurate as bulb lumens.

The HO-6 is their beefiest 6V lamp assembly- uses about 1.4Amp off of a pair of photo batteries... compared to the 2.4Amp that the P61 yanks. It's going to be brighter and probably whiter than a P60, but the P61 will have more total lumens out the front... however, the P61 is going to be a much floodier beam, so they are hard to compare accurately. All of the lamps available should be taken into consideration because there are strong points to all of them.

[edit in 4/15/17] just noticed: EO-6 now available, 1.9amp, pretty close to a P61 now.

To get in the ballpark of P61 lumens but with more throw, a pair of AWs Protected RCR123s and a LF HO-9 is the best way to get there. If I had a C2 That's the setup I would use in it, and probably buy a whole bunch of rechargeables (only $6 each, so owning a dozen plus charger would still be less than the cost of the C2, and would save a lot of money in the long run)


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## nikon (Feb 28, 2007)

I much prefer the Z2 and G2Z over the C2. I find the square body of the C2 much less comfortable to grip and I find that the pocket clip gets in the way. I think the Z2 looks better than the C2, although I may be in the minority on this.
The Z2's lighter weight and more comfortable grip make it the light of choice for me. I've had several C2's and sold them all.


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## bridgman (Feb 28, 2007)

I also went with the Z2 -- it's smaller and easier to grip. In all other respects the C2 is nicer. If there's any chance to hold them both before buying that would be ideal.


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## Cerbera (Feb 28, 2007)

I went with a Z2 as well. Recently bought AW's 100 lumen lamp and 17670 protected batteries. Nice setup. I would go with the HO-9 and two protected RCR123s if I really need more lumens and sacrifice the runtime.


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## ScooterBug (Mar 1, 2007)

i have a Z2 that is issued to me at work, been a great light. i just recieved a new GZ2 and i like the feel of this one better. have no intrest in the pocket clip on the C2.


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## search_and_rescue (Mar 1, 2007)

I would go with the Surefire C2-HA Centurion in Mil Spec Type III Hard Anodizing. I used to own a Surefire C2-BK Centurion in Mil Spec Type II anodizing, and I regretted not buying the Surefire C2-HA Centurion with the Mil Spec Type III Hard Anodizing for ten dollars more. 
Thank you. :rock:


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## jsr (Mar 1, 2007)

Mac Swift - Check out lighthound.com . He carries a complete head that's crenellated, but it only comes in black. Honestly, if you're that close to hitting someone with the bezel of your light, I'd rather have a knife or other weapon on me.


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## Mac Swift (Mar 1, 2007)

hey thank you all for your thoughts, my appreciated.
JSR...thanks for the link, just when im using the light with my pistol, if worst case i didnt want to shoot him, nor hit him with my 1000 dollar HK, id rather hit him with the flashlight because both hands would be too tied to grab my knife. id rather have it, and not need it,that to wish i had it when i could have used it.

SEARCH AND RESCUE , so it is true, i read that L1 has been updated but nothing was mentioned on thier site, so i didnt think much about it. that is LED though, and as much as i love the LED, i too would love the L2 or even L4, but id have to save up for that , my toys are getting pricey right now i need a good light that i can count on for around the 100buck range and not be let down by some of the other lower range lights that keep letting me down. oh for what its worth i have a TLR 1 SL on my HK USP which is led ,,this is for extra light plus its better pulling out a surefire to light up somthing apose to ur HK ,,,some people might get the wrong idea.


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## Mac Swift (Mar 1, 2007)

just found the G&P Tactical Head for SureFire on the lighthound website. will it fit the z2 combatlight ? it doesnt say that it will, but it also doesnt say that it wont, because all the lights it lists are pretty much the same light, just curious that if anyone has this onthe z2? or any info,,, are all the heads with the same p60/61 lamps the same specs and interchangable ? would i need anything for that combat head to work with the z2 ?


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## Cerbera (Mar 1, 2007)

It is a direct screw on. It should be no problem.


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## Mac Swift (Mar 1, 2007)

hey cerbera .
. can u explain ur z2 setup a little more for me. with your 100 lumen and protected batteries . what are different about protected batteries apose to the surefire 123. and whats ur runtime? i think 20mins with 120 is pretty quick but i like the sound of what ur running ... i think im swinging to the z2 now if i can get that impact crown, and get another light later down the road with the HAIII coating,


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## Mac Swift (Mar 1, 2007)

and also ..how many lumen do you get from Lighthound Cree Drop-In LED Bulb, and what sorta runtime are you looking at ?


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## mdocod (Mar 1, 2007)

Mac:
the 100 lumen with protected cells is referring to the following setup:
G&P makes many lamps that fit in the same place that P60 lamps fit (as well as P90 lamps)... They make a 3.7Volt version designed to be run on a single lithium-ion rechargable cell. Wolf-Eyes and LumensFactory also make lamps designed to run with this configuration.
In the world of lithium and lithium ion batteries... it is important to understand that lithium primary cells (surefire cells) are about 16mm diameter by about 34mm long. They are sometimes referred to as 16340 sized cells. You probably already know that they deliver about 3 volts, and have a capacity of about 1300mah. So a pair of these cells in a light like the C2 powers the 6V lamp nicely...
Now.. Lithium-Ion rechargable cells differ from this in that, they are more like 3.7V, so a pair of 16340 sized lithium-ion rechargeables would blow a 6V lamp, but a single cell would underpower it, producing a yellow lousy output. So, generally speaking, when we want to use rechargable lithium-ion cells in a light, we use one of the following 3 configurations. 
1. a 3.7V bulb powered by 1 Lithium-Ion Cell.
2. a 9V bulb powered by 2 Lithium-Ion Cells.
3. a 13V bulb powered by 3 Lithium-Ion Cells.
There are many options in each range... For light like the C2 that have room for 2 CR123 (16340) sized cells, you have 2 configurations available. "1" and "2" above.

Now it is also important to understand, that there are many different Sizes of Lithium-Ion cell available, and many different brands, and there are also Protected Cells, and Bare Unprotected Cells.
There are 3 brands of cell you will find in a flashlight at CPF more than any other cells out there...
1. AWs Protected Li-Ions, available in many sizes... they are available at Lighthound and through his sales thread in the dealer section of this forum.
2. Wolf-Eyes Protected Li-Ions, available from Pacific Tactical Solutions
3. Pila Protected Li-Ions, available from Jsburlys

These are the most commonly used because they are the best quality cells available, and they have protection circuits that make them safer than ordinary "bare" lithium-Ion cells. These 3 brands of Protected cells are the only protected cells on the market with high current thresholds set on those protection circuits, this is done specifically with the intention of being able to light up powerful incandescent bulbs. I do not recommend unprotected cells, or any cells that claim to be protected from other sources.. Going on ebay and picking up some really cheap cells is asking for trouble.

Ok... now back to some more specifics about the setup. Obviously your C2 will have room for 2 16340 sized cells, but if you wanted to use a 3.7V lamp, it would be rather wasteful to use a cell that only fills half the tube... The good news is, there are longer cells available.. specifically, for this application We're talking about a 17670 sized cell. AW calls it a 17670 sized cell. Pila calls it a 600S size cell, and Wolf Eyes calls it a 168B sized cell... But they are all approximately 17mm diameter (which fits snug in most lights designed for 16340s, like the C2) by 67mm long. This single cell, fits in the place that 2 CR123s (16340s) would ordinarily fit. Provides a 3.7V output with a rated capacity of 1500-1600mah depending on the cell. There are many other common cell sizes available for Li-Ion rechargable cells. 10440, 14500, 14670, 16340, 17500, 18500, 18650. Various arrangements of cell configurations are being used by many CPFers to power bulbs and LEDs...

Now.... lets say you go with the 17670 cell, and a 3.7V lamp. You can expect the light to be brighter than th stock P60, but dimmer than the optional P61. The 3.7V lamps draw more current that a P60, so what they lack in voltage, they makeup for in current to be reasonably bright. The P61 is a hog on current, sucking 2.5amps on average. Runtime on a 17670 cell is 35-50 minutes depending on what lamp you choose.

Now.. lets say you wanted a configuration that is closer in output to the P61 that is also rechargable. 
You would want to step up to a 9V lamp, and run a PAIR of rechargable RCR123 (16340) sized cells.(3.7V each, fresh off the charger these are more like 4.2, for a total of 8.4V for 2 cell in series fresh off charger.. Li-Ion suffers from less voltage sag than lithium primary cells under a load so this drives it about the same brightness as you get on 3 3V primaries) These cells are generally rated about 750mah capacity. The only RCR123 cells available WITH protection that will light up 9V tactical lamp assemblies reliably are the AW protected R123s. Don't bother with any others, these are good cells. Keep in mind, that Most of these cells are designed to be used up to a 2C current draw, no more... So for a cell with a 750mah capacity, you should never use a bulb that draws more than ~1.5amp. For a 1500mah cell, 3 amps would be the max... Some cells are rated lower than this so make sure you know what you are getting before you buy. With AWs protected R123s, he brightest lamp you can safely run is made by LumensFactory and is called the HO-9. Draws almost exactly 1.5amps on R123 cells. It's similar in total lumens output to a P61 but with a more concentrated beam.... Runtime would be about 20 minutes.


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## Strauss (Mar 1, 2007)

Wow, very imformative post mdocod :goodjob:


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## Mac Swift (Mar 1, 2007)

---- i second that 
WOW mdocod .. you are the MAN ! thank you so much. that taught me alot. 
i will for sure look into that for my mods for the surefire.. 

im saving this thread as pdf thats for sure... lol


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## zx7dave (Mar 1, 2007)

As far as the strike bezel from lighthound. It is nice and sharp and well built. Also works very well with the Cree P4 dropin. With the stock bezel you usually can screw down teh bezel all the way since the Cree is longer than the stock P60/61. The bad part is that it only comes in black.
If your looking for this to be a defensive weapon and you happen to choose the C2 (which is great light), you might want to take the clip off which will help your grip. You won't have a lot of bezel options, but the end of the light is still a hell of a lot harder then your fist and can make a effective weapon. By the way make sure you never bring a flashlight to a gun fight 
You can run the KL3, and KL5, but I think the KL6 is intended for the M series lights only, unless you use a adapter.


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## Mac Swift (Mar 2, 2007)

MDOCOD. i can you please clarify somthing for me, yes more questions, just trying to get an understanding on some setups. i was doing some reading and i like your ideal setup thats the pair of aw's rcr123s and an LF HO-9.. but i read that on those cr123s you cant drain them all the way down before you recharge them. somthing about damaging them? how do you do this. how do u know when to recharge them. and if your getting 8.4volts on a fresh charge and ur not giving the full 9v you obviouslly lose some lumens and power right ? what would you be getting with those 20mins in aprox. lumens? or would you get the full 320lumens?

"Most of these cells are designed to be used up to a 2C current draw, no more " what do you mean by this ?

also how many cycles do you usualy get on those AW cr123s before you want to chuck em ?

also i picked up a z2 combat, got a killer deal on it, and thought id use the extra cash to mod the crap out of it. also kept it black as im going to get the strike bezal. (which is black) and i went through 4 surefire 123s today playing with it, and have decided ..time for rechargables. but those aw 123s will blow my surefire p60 lamp right ? 

i have the idea that iwant to get the HO9 setup with the aw rcr123s, for my HI short term setup . 

but i also want to have a LED setup that will be high as well but with a longer runtime.
i was looking at the cree drop in.. can i use those aw rcr123s with that led setup. or whats a good LED setup that has HI lumens and good runtime?

THANK YOU all for your imput on helping me make my purchase im really happy, and also felt the z2 felt better in my hands than the c2. 

and ZX7dave..... about bringing a flashlight to a gunfight . LOL...


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## mdocod (Mar 2, 2007)

I'll see if I can clarify some more... (I was equally confused and overwhelmed with information when I wanted to switch to Li-Ion TOO!, it's a lot to take in and learn all at once) We'll break it down one at a time..



> but i read that on those cr123s you cant drain them all the way down before you recharge them.


First lets make sure we nail down the naming structure so we don't confuse the situations further. When we say CR123, we are talking about a 3V primary cell, which is more formally seen called a CR123A.. (stands for one, two-thirds of an A size cell), I think the A gets tossed by a lot of us in communication (including myself), probably because it takes longer to type, lol.. so you wouldn't want to recharge that. The names I've seen used for a rechargable Lithium-Ion that is the same size as a CR123 primary, are RCR123, R123, 16340 Li-Ion. Seems like we get a lot of Various forms of terminology for the same cells, anytime it begins with an "R" the writer usually is intending to discuss the rechargable format of the cell.. the term 16340 is a slightly looser term because it is really only referring to size, but can be used in in the context of discussions about lithium-Ion because it is a well known way to talk about a Li-Ion cell. (and it would be a very rare way to talk about a CR123A primary)....

OK that's out of the way... back to where we were...
Lithium-Ion chemistry must be respected.... There are particular rules that must be followed in order to keep the cell in safe working condition: for most cells this means the following things:
do not charge above 4.2V
do not discharge below 3.0V (some cells are as low as 2.5V)
do not discharge faster than 2C (some cells as low as 1C)
do not charge faster than 1C

Now... Here's the good news. #1 and #2 are taken care of for you when you buy quality cells and use a good charger or monitor a cheap one... The cell will shut down before you inadvertently over discharge it or over charge it. This is why you want to buy PROTECTED cells. It will leave some of the guesswork out of using Li-Ion cells. Most chargers are pretty good about charging correctly, but it would be wise to invest in a multimeter and test the voltage of the cell before it goes on the charger, and after they come off. Doesn't need to be done EVERY time, but at least once and awhile to make sure everything looks right (this way you know if cells are staying matched well or not, also it tells you about how long you have to charge it). Testing after they come off the charger lets you know if the charger is doing it's job- if you see 4.3+ V then you should monitor charging closely and pull cells for testing frequently until you have a chance to try a different charger.. For the most part, I have had good luck with cheap Li-Ion charger like the Ultrafire and the DSD ($7-15).. but I closely monitor and always pull cells as soon as the light goes green (leaving it on the chargers seems to trickle the cells up beyond a good safe point). 4.25 is considered OK, 4.4 is where danger begins. My RCR123s from AW always seem to come off the charger at about 4.16V, which is a nice healthy point to stop.



Ideally speaking, even though you are using protected cells, You should mentally keep track of how much runtime you have used on the light, and watch for dimming. When the light starts to seem noticeably dimmer and orange-er in color output, you should plan on recharging as soon as possible. The cells will protect themselves from being over-discharged, however, cycle life is much greater when you use shallower cycles on Li-Ion. So maybe use the light a few minutes a day for various tasks and charge it up every other day. The nice thing about Li-Ion is that it does not develop memory issues, you never really need to do "forming charges" and "full discharges" and stuff like that. Might be good to give them a full charge followed by long run followed by full charge when you get them to break them in, but after that just pt em on the charger when ever you want to top them off. Daily would be fine even if you use the light a little bit during the day. Li-Ion cells also have little to no self-discharge. So you can charge it up and know you could come back to that light in a month and have full juice ready to go...



> if your getting 8.4volts on a fresh charge and ur not giving the full 9v you obviouslly lose some lumens and power right ? what would you be getting with those 20mins in aprox. lumens? or would you get the full 320lumens?



Let me begin by saying- if you took a 9V tactical lamp assembly, made by Surefire, LemensFactory, anybody.... doesn't matter, and put it on a bench power supply and set it to 9V, it would not last very long at all. Especially the high power ones like the EO-9 and P91, which would probably instaflash at 9V. The HO-9 might last a few minutes to an hour if your lucky. The lower power bulbs might last a little while, the very lower output bulbs (less than an amp) would probably work fine on 9V...

Now.. here's why. This is hard to follow because it's one of those double reverse things where it is the way it is because of the way something it is this way..bleh.. I'll try....

CR123A primary cells, when BRAND new, fresh out of the box, measure about 3.2V per cell. However. When you put a load on them, that voltage does not stay 3.2. This is the case with ALL batteries. They have an open circuit voltage, and they have a working voltage. Depending on how much you demand from the cell (in amps) will determine how much variation there is between open circuit voltage and working voltage... Please Refer to Silverfoxes charts of CR123A discharge characteristics here https://www.candlepowerforums.com/threads/67078 
You will see that at 1 amp, most cells almost immediately sag to 2.5V. 

Now, most standard 9V lamps are from 1.1-1.3 amp. The HO-9 is about 1.5amp. At 1.5amp we can expect the average CR123A cell to sag to about 2.4V within a few seconds of being fresh. 3X2.4V=7.2V
So.. when designing high power tactical lamps, they take this into consideration.. They need the lamp to be able to survive that initial high-voltage spike of the first few seconds, but they try to make the bulb in such a way that it will run strong and bright far below 9V, because in reality, the bulb will rarely if ever actually get 9V after the voltage sag of the batteries under a load.

Take a look under "lamp specifications" at this page: http://www.lumensfactory.com/d26_series_specification.htm
you'll see they have designed the target voltage for 9V lamp to be 7.6V. smart eh? 
Also take note of the EO-9, which is a 7.2V lamp... this is because it draws 2.0amps and sags the voltage of the cells down even further. they took this into consideration when designing this lamp, by doing so, it is brighter and whiter off of the cells it was intended to be used with.

Now... Here's the deal withe Li-Ion.
Yes they do only come off the charger at 4.2V (8.4V total for a pair in series). But as you can see above, the fresh voltage of a cell says very little about the way it works under a load. GENERALLY speaking, Lithium Ion cells suffer from less voltage sag than Lithium Primaries. As a result of this, the ideal voltage range for running a 9V tactical lamp is reached without a problem. Now.... Ordinarily speaking. The ideal setup is to use a 3 cell light like the C3 or 9P or something. This way you can use larger cells. For example. A pair of 17500 size cells are a direct replacement for a set of 3 CR123s. The larger higher capacity cells will also perform as well or better than the original configuration of 3 CR123s.. When you step down a "notch" in size and try to run powerful 9V lamp assemblies off of small RCR123 cells, depending on the cell, you do loose a little bit of performance and a lot of runtime trying to get so much out of so little... but if compact size and bright are important, then we make these sacrifices. As far as real world use goes, you wouldn't be able to tell much different between a HO-9 on a pair of RCR123s to a HO-9 on 3 CR123s... in fact, it's hard to distinguish the difference between LFs HO-9 and EO-9. The human eye just isn't a very good light meter. On a pair of BIG Li-Ion cells like 17670s, the HO-9 runs at about 1.6amp. On the small RCR123s, it runs closer to 1.55amp quickly diminishing to 1.5amp where it stays for awhile.... So a bigger set of cells will run a little brighter, but you can't see much difference. For long runtime, many people are using "4 cell" sized bodies (length of 4 CR123A cells) that are bored to accept 18mm diameter cells... a pair of 18650s gives about 2200mah capacity instead of the 750mah you get from a pair of RCR123s, So they can drive even more powerful lamps, or run the regular ones much longer. But at the sacrifice of space...



> "Most of these cells are designed to be used up to a 2C current draw, no more " what do you mean by this ?


The "C" rating is the multiplier to discover the maximum safe discharge and charge characteristics.. I mentioned those characteristics above... Now I'll explain further..

It's quite simple really: easiest thing for me to do is give examples:
cell 1 example:
18500 sized Li-Ion Cell
1500mah capacity
2C max discharge
1C max charge
take the "2" before the C for max discharge and multiply by the MAH capacity rating of the cell. 2x1500=3000MA max discharge. or 3Amps. same for charge, 1x1500=1500, this cell can be charged at 1.5amps, no more..

cell 2 example:
26650 size Li-Poly<-
3100MAH capacity
10C max discharge
4C max charge
Take "10" X 3100 = 31,000MA max discharge... 31 amps. wow! (some Polymer cells can do this... RC guys use stuff like this)
"4"Cx3100mah = 12.4amp max charge rate... This cell could be safely charged from dead to full in about 15 minutes without damage.


Ratings like this are given to all sorts of batteries... You just take the C rating and multiply by capacity to find out the maximum current allowed for that function..

There are some batteries specifically designed for the safe delivery of up to a hundred amps or more.

Unfortunately, The cells we use, aren't so advanced just yet. Most of the Li-Ion cells we are using are rated between 1.5 and 2C... For the little RCR123s sold by AW, you take "2C" and multiply by 750mah.... you get 1.5amp maximum safe discharge...

As you can see.. the HO-9 is right on the limit, even pushing a *little* over the limit for a short while... which brings us to the next very logical section:



> also how many cycles do you usualy get on those AW cr123s before you want to chuck em ?


If you choose to drive a HO-9 on these cells, you will be working the cells hard. Normally Li-Ion cells are good for anywhere from 300-1000+ cycles depending on how they are used.. If you are talking about running the light for 5 minutes a day, and charging every night. Then you could get a LOT of these shallow cycles out of it.. probably 300-500 cycles. as long as they aren't over charged often.. If you discharge it till the cell shuts off (protection kicks in) every time you use it, then I would plan on more like 100 cycles or less at this drain rate.. 

in any case, after 2 years, the cell should be up for evaluation if not replacement if it has been used a decent amount. A good rule of thumb is when a cell is performing at 80% of it's original "new" capacity, it's time to chuck it.



> went through 4 surefire 123s today playing with it, and have decided ..time for rechargables. but those aw 123s will blow my surefire p60 lamp right ?


The whole reason so many of us are going rechargable is to be able to just play, guilt free. Showing off a fancy light shouldn't come at the guilt of knowing that it is sucking down 2-10+ dollars an hour (depending on configuration) in primary cells. Having rechargeables in a light also lets you use it for more tasks where it is handy, but maybe not necessary, without feeling that guilt of coming that much closer to dropping in more and more cells.

A pair of 3.7V RCR123s would blow your P60 into the next dimension. Don't try.


Higher up there you asked about lumens... "would you get the full 320 lumens."... 
All I can say here is.. try not to get too hung up on lumens.. (I do all the time, but I shouldn't)... For starters, there is such a massive difference in the way different manufactures measure and rate lumens, that you cannot compare the numbers, you have to know the lamps first hand, or have a really good idea of how they were rated to get the number..

The best way to compare incandescent lights... is to compare power consumption. 
Your P60 is a ~5V lamp that draws ~1.2amp. it's about 6 watts of light. The HO-9 is ~7.2V on fresh RCR123s at about 1.55amp, or about 11watts...it's about twice as bright. By comparison, a P61 is about 4.5V in operation by about 2.5amps, which is also about 11W... notice how the P61 is rated 120 lumen by Surefire, The HO-9 is rated 320 lumens by LF... and believe it or not... both companies have a legitimate number, because they measure differently. Surefire is talking about torch lumens at some point during the discharge (like with half used batteries)... LF is talking about bulb lumens on fresh cells. I think Surefire also derates even farther than that... It's nuts how underrated some of their lamps are.




> but i also want to have a LED setup that will be high as well but with a longer runtime.
> i was looking at the cree drop in.. can i use those aw rcr123s with that led setup. or whats a good LED setup that has HI lumens and good runtime?


I'm not as "in the know" about the LED stuff going on.. But as I understand it there are some Cree Drop-In modules that will work on 3.7V-9V input. So you could run them on the RCR123s, or run them possibly longer on a single 17670. maybe Someone else could chime in here with more details.

glad you found your new light! sounds great! 
cheers!


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## DM51 (Mar 2, 2007)

Brilliantly well explained, mdocod. That post should be a sticky all by itself - very fine writing indeed. Required reading for all those who want to understand!


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## Strauss (Mar 2, 2007)

Mdocod is correct, the CREE drop-in is rated for 3.7-9V. So you will be fine with your 2xRCR123's. Matter of fact, my drop-in should be here today, which I plan on running it on 2x17500's in my C3.


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## mdocod (Mar 2, 2007)

> That post should be a sticky all by itself



After looking at how much I just typed (I get lost in the moment and just keep blabbing and not even realize how big a post is getting)... and reviewing my post.. I wonder if we could have it arranged to go into a sticky "semi guide to Li-Ion" somewhere... along with post #25.. save the trouble of trying piece together so many odds and ends each time someone wants to learn of Li-Ion setups... Could just link to this to get things started.. We have lots of information here on CPF about Li-Ion, but it's really overwhelming for a newcomer to gather it all and make sense of it (I should know, that used to be me, I have Paul_In_Maryland and others to thank for all they taught me me back in the day)....


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## zx7dave (Mar 2, 2007)

Great info...Thanks!!!!


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## Mac Swift (Mar 3, 2007)

MDOCOD . thank you so much for that well written, easy to follow explanation of lithium ion , that was seriouslly going the distance, and im nothing but enlightened and appreciative. it really is overwhelming to have a bunch of garble that you only half understand thrown in your face from a 100 different directions, you summed it up very fast and really clear for me. if you were wondering i am going to go with your original setup with a pair of aw rcr123a's (will buy several sets to always have a fresh charged pair available) and the LF HO-9 and and will also be getting the the ultrafire charger. i dont think i will have a problem over charging the cells or leaving them on the charger for too long. im very good about that (cell phones,laptops so this shouldnt be a problem) 
and for the LED setup i think i will getting that cree drop in as well. just to have for those days i need a longer runtime. 
im not that big of a fan of the LED output as i am of incandescent, but its useful from time to time.

and i also agree that this should be made a sticky,very very informative. and helpful

thank you very much again.


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## mdocod (Mar 3, 2007)

glad to hear you decided on that setup.... it'll be awesome!

glad I could help! 

cheers!


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## mdocod (Mar 18, 2007)

tag


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## mdocod (Apr 12, 2007)

tag


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## Glen C (Apr 12, 2007)

Mdocod, two great clear posts by you, extremely well explained







.


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## Outdoors Fanatic (Apr 15, 2007)

Great post!!


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## mdocod (Apr 15, 2007)

I'm trying to keep track of it.. when I get a chance, I want to copy paste some stuff from this thread, and some others, add to it, and make a "thread of interest".. with any luck, I can get an admin to put it in the threads of interest section.


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## DM51 (Apr 23, 2007)

mdocod said:


> I'm trying to keep track of it.. when I get a chance, I want to copy paste some stuff from this thread, and some others, add to it, and make a "thread of interest".. with any luck, I can get an admin to put it in the threads of interest section.


That is a very good idea. I've steered other people to your post #30 here several times already, as it is just such good and well-explained info. A collection including this and others would be very useful.


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## mdocod (Apr 23, 2007)

I've since moved the responses in this thread to parts of my "li-ion incan guide" which can now be found linked to in my signature.... it's in the incandecent section, but hasn't been put in the "threads of interest" yet.


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## DM51 (Apr 23, 2007)

Just looked at your guide - fantastic work! Very very good indeed - extremely useful.


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