CR123 and 18650

Can you substitute an 18650 battery for 2 CR123 in a SureFire 6P? I have an old 6P (about 10 years old). The Cr123's with the high output lamp die in appx 20 minutes. Instead of buying rechargeable 123's I was wondering if I could use rechargeable 18650's.
Thanks,
Steve

They don't fit.

No, an 18650 is too fat.

18650s are 2mm wider than cr123As...17670s are a better candidate

First, a 18650 will not run the high output bulb. Not enough voltage. Second, an 18650 is too wide to fit in a 6P. You will need to find someone that can bore it out, preferably with a lathe.

Illum said:

17670s are a better candidate

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+1

Too bad there aren't any IMR 17670 cells....

Illum said:

18650s are 2mm wider than cr123As...17670s are a better candidate

Click to expand...

I got one of those for my G2 Green KL3. Sounds like my 17670 will replace 2 CR123s! I wonder if the runtime will improve.

lolzertank said:

First, a 18650 will not run the high output bulb.

Click to expand...

y not?

For about 3 bucks you can always convert your surefire to a 3.7 volt 10w bulb from DX but you'll still have to bore it out.

Splunk_Au said:

y not?

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3.7v is a bit shy for the P61.

Hwy115 said:

Can you substitute an 18650 battery for 2 CR123 in a SureFire 6P? I have an old 6P (about 10 years old). The Cr123's with the high output lamp die in appx 20 minutes. Instead of buying rechargeable 123's I was wondering if I could use rechargeable 18650's.
Thanks,
Steve

Click to expand...

Just get 2x IMR 16340 cells and run any of these 9V lamp assemblies in your 6P: P90, ES-9, SR-9, HO-9, EO-9, IMR-9 or P91. Don't bother with the P61.

Marduke said:

3.7v is a bit shy for the P61.

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ah i see, was assuming the op meant the LED 6P.. seeing as how its in the LED forum and all.

OK, then why are there lights like the Jetbeam RRT-2 which use both the CR123 and the 18650? Is thetube bored out to handle the larger battery and then what happens if you put in the smaller batteries? Are they loose within the tube?

Hwy115 said:

OK, then why are there lights like the Jetbeam RRT-2 which use both the CR123 and the 18650? Is thetube bored out to handle the larger battery and then what happens if you put in the smaller batteries? Are they loose within the tube?

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Led lights usual has a circuit to drive the led, this circuit is designed to accept a voltage range, for the RRT-2 and many other lights in that size the voltage is 3+ volts. But usual they will first reach maximum output when the voltage is somewhere between 3.7 to 4 volt.
They also have a large inner diameter in the battery tube, i.e. CR123 can rattle (OLight includes a battery container to prevent that).

The curve below shows the light output and current draw at different voltages for a 18650/2xCR123 light:

Hwy115 said:

OK, then why are there lights like the Jetbeam RRT-2 which use both the CR123 and the 18650? Is thetube bored out to handle the larger battery and then what happens if you put in the smaller batteries? Are they loose within the tube?

Click to expand...

I just got a Malkoff MD2 that can accept 2xCR123 or 1x18650. I wouldn't say that 2 AW 16340's rattle around, but if I wack the light on my palm, I can hear them. The AW 18650 fits a little more snuggly.