SureFire G2 LED, need a little help?

Hey guys I am really new at this so please be patient with me. I have a quick question for you guys. I have a SureFire G2 LED, and I was wondering if I put this drop in, in it. How many lumens would it put out with just the two CR123 batteries in it?
Does it still put out the 250 lumens, just for not as long or what? If so how long you think the batteries would last?
Thanks, Chet

What drop-in are you considering? I would suggest a malkoff M60 if you want ~250 lumens.

Eh dummy me, I forgot to post the link. http://www.lighthound.com/Lumens-Factory-D26-LED-36-13-volt-250-Lumens-Lamp-Assembly-for-SureFire-C-P-Z-Series_p_2620.html##

Thats the one I was looking at. I'll check out the malkoff to though.

Lumens factory makes good stuff, so I would guess that is a decent drop-in. Probably well worth the price. The malkoff is probably worth the cost (double) as well, its just a matter of how much you want to spend. Check this thread for info on a bunch of drop-ins.

Which one you think would last longer? I know leds are supposed to last a long time, but as far as all the electronics in it, which is better made. And actually puts out the lumens it says it will?

I don't know if this is the right approach, but it would seem like if at CR123 has about 1400 mAh at 1.0 amps ( I got that figure from this thread: https://www.candlepowerforums.com/threads/67078 ) so 2 cells will give you 2800 mAh. The light draws 1000 mA....so under ideal conditions if you could get the battery to completely drain it would last for 2.8 hours. However, your actual results will be less because the cells will provide a declining voltage until it gets below the point where it can light the bulb. I'd guess 2 hours or so....but that's a lot more guess work than actual math. I'm not sure my math method is sound. It seems odd to me that a CR123 would be rated at 1400 mA when a plain old AA rechargeable is almost twice that.

GPB said:

I don't know if this is the right approach, but it would seem like if at CR123 has about 1400 mAh at 1.0 amps ( I got that figure from this thread: https://www.candlepowerforums.com/threads/67078 ) so 2 cells will give you 2800 mAh. The light draws 1000 mA....so under ideal conditions if you could get the battery to completely drain it would last for 2.8 hours. However, your actual results will be less because the cells will provide a declining voltage until it gets below the point where it can light the bulb. I'd guess 2 hours or so....but that's a lot more guess work than actual math. I'm not sure my math method is sound. It seems odd to me that a CR123 would be rated at 1400 mA when a plain old AA rechargeable is almost twice that.

Click to expand...

Two CR123, each 1400mAh will give you about 6.50 volts at 1400mAh. The available watt/hrs will 6.5 X 1.4A's = around 9 watt/hr. One CR123 about 1/2 of that. One high cap AA NiMh would have maybe 3.26 watt/hrs. So you can see the advantage of the CR123 cells.

Bill

How well would one of these work with regular cr123 batteries?

The drop-ins are almost all buck circuits, which mean the input voltage has to be higher then the LED's needed voltage (and be within what the driver can handle). A good circuit should maintain the same current to the LED (and hence output) as long as the battery voltage is within it's accepted voltage.

My guess is that the drop-in puts our around 250 lumen at the LED, which means 170-200 lumen out the front (approximate numbers).

An AA battery has half the voltage of a CR123 battery, so in order for both to have the same capacity, the AA battery has to have 2x the mAh. 1.5v * 3000 mAh = 4.5 watt hours, 3v * 1500 mAh = 4.5 watt hours

So if you use regular cr123 batteries with the M60 malkoff. What run time would you get with two of these batteries.

Do some reading on the Malkoff M60. For example use google, cpf only, at the top of every CPF page and plug in something like G2 + M60 and see what happens. Lots of threads will probably pop up with useful info on using the M60 in the G2. Also go to Malkoff's web site and look up what he recommends for the G2, which M60 type he recommends. Someone will give you some info here, but more to be had by searching for it yourself.

Bill

thanks for the clarification on the CR123 vs AA Rechargables.

Bullzeyebill said:

Two CR123, each 1400mAh will give you about 6.50 volts at 1400mAh. The available watt/hrs will 6.5 X 1.4A's = around 9 watt/hr. One CR123 about 1/2 of that. One high cap AA NiMh would have maybe 3.26 watt/hrs. So you can see the advantage of the CR123 cells.

Bill

Click to expand...

Apples and oranges. Comparing apples to apples, and oranges to oranges:

Comparing lithium primaries:
CR123 ~ 4Wh
L91~4.5Wh

Comparing rechargables:
RCR123 ~ 2.6Wh
2700NiMH ~ 3.24Wh
LSD NiMH ~ 2.64Wh

So in terms of actual stored energy, AA format wins on both fronts.

You can find the runtimes on all of his modules on the malkoffdevices website. The M60's output 205+ otf lumens for 1.5 hours, with a couple hours of declining output after. M60L's and LL's for 4+ and 8+ hours respectively. The M60 MCE runs for 45 minutes. All these runtimes are on 2xCR123A batteries. If your G2 has a metal bezel then gene says that will be enough for reliable operation with his standard M60. If it's a plastic bezel light then no more than 15 minutes at a time or the module (and this goes double for other dropins) will run the risk of overheating damage. As a matter of personal preference, I'll suggest getting an M60W or M60WL. They both give up about 40 lumens compared to their normal tinted cousins, but the quality of light from those 5A emitters more than makes up for it.

Marduke said:

Apples and oranges. Comparing apples to apples, and oranges to oranges:

Comparing lithium primaries:
CR123 ~ 4Wh
L91~4.5Wh

Comparing rechargables:
RCR123 ~ 2.6Wh
2700NiMH ~ 3.24Wh
LSD NiMH ~ 2.64Wh

So in terms of actual stored energy, AA format wins on both fronts.

Click to expand...

GPB was comparing AA rechargeable to CR123, thus my response. Don't understand your post I guess.

Bill

Bullzeyebill said:

GPB was comparing AA rechargeable to CR123, thus my response. Don't understand your post I guess.

Bill

Click to expand...

For an accurate comparison, you need to compare rechargable to rechargable, primary to primary.

Marduke said:

For an accurate comparison, you need to compare rechargable to rechargable, primary to primary.

Click to expand...

No, not in this case. He was discussing CR123 and rechargeable differences. Read his post that I responded to.

Bill

sorry to have caused such confusion. I was just trying to calculate the run time of the drop in and looked up the mAh of a CR123 in another thread. I was surprised that they had a rating lower than what I was used to for AA rechargeables. The only reason I compared them to AA rech. is because those are the only batteries I know of that have the rating printed on them. I had always assumed that CR123 had considerably more power in them that AA's because: they cost more, they are lithium, and they seem to be the main power source for really bright flashlights. Now after Marduke's post I'm confused again...he seems to indicate that AA have more power...then why do the high power lights use the CR123's ? I should probably head over to the battery section and spend a little time there.

They have slightly more power than an AA. You have to multiply voltage * mAh to get a useful estimate of total capacity.

GPB said:

then why do the high power lights use the CR123's ? I should probably head over to the battery section and spend a little time there.

Click to expand...

It's actually very simple. Back in the late 80's, a company called "Laser Products" (now SureFire) starting making compact weapon lights. This was still incandescent time, and more voltage = more brightness. To pack the same wallop as the other "bright cop light" at the time, the 6D Mag, they needed more voltage in a smaller package. So they used two of the 3v lithium camera cell batteries called CR123's. Compared to the tech at the time (nicad, alks, carbon zinc), these cells were extraordinary.

Fast forward to the 21st century, where white LED's operate of a very narrow voltage range of ~3.2-3.7v and use a circuit to regulate the voltage. Having 6v in such a small package is no longer of real benefit.

However, the image that high end lights should use the same "high end" power source that they have used for the past 20 years is still ingrained in the psyche of many people. Many of the benefits that format held 20 years ago are now pointless, and the rest can be had in other formats as well which offer other advantages such as lower cost or safer operation.