1x18650 3.7 volt / 2xRCR123 7.4 volts ???

[takthekak]

Are 2 RCR123 batteries going to produce twice the voltage output as an 18650?

Would an 18650 tend to be brighter, or dimmer in a flashlight that accepted either configuration?:thinking:

 

[Quension]

Are 2 RCR123 batteries going to produce twice the voltage output as an 18650?

Two RCR123 batteries in series (e.g. end-to-end) are, yes.

Would an 18650 tend to be brighter, or dimmer in a flashlight that accepted either configuration?:thinking:

That depends entirely on the flashlight's driver. Some flashlights respond to more voltage by getting brighter, while others are regulated to maintain steady output within a specific input voltage range.

 

[takthekak]

Thanks for the info!

 

[bandersnatch]

Would an 18650 tend to be brighter, or dimmer in a flashlight that accepted either configuration?:thinking:

Based on the graphs I've seen of output for 18650 lights, the broader the voltage range that a flashlight can handle, the harder it is to regulate the light at maximum power and low voltage. So running an 18650 in a Jetbeam III-M on max will give you a brief period of full regulation followed by steadily declining output (see Selfbuilt's review). If you want a light that will stay at maximum brightness until the battery is depleted, you're almost certainly going to have to go with a light with a small voltage range.

 

[Lupino.86]

In my Romisen RC-B12 I have more lot of light with 2xRCR123... very brillant white
With 1x18650 I have dirty white and poor light (sensible diference)

 

[Conan]

My Fenix TA 21 gives the same brightness whether you use two CR123, two RCR123 or one 18650. I can't explain how exactly they were able to do it with this light.