2xRCR123 vs. 1x18650 Voltages & RC-M4 + 18650

[egroeg555]

As far as I know, when you put 2 batteries in series, the voltages get added. How does a flashlight that can take 2xRCR123 as well as 1x18650 deal with this voltage difference? This is like 7.2 vs. 3.7. Does it simply run at a higher current, or can it regulate to deal with the voltage difference? I realize this is a total noob question, but I couldn't find the answer anywhere.

Also, this is in reference to the Romisen RC-M4 II Q5 on shiningbeam.com, which I'll most likely be buying. I have read that this takes some 18650 batteries, but others don't fit. After looking around, I still do not have a definitive answer on which 18650's fit and which to not. I'd rather not buy some and find that they do not fit. Does anyone know which 18650's fit the RC-M4? If you own the RC-M4, what battery configuration do you use?

 

[old4570]

Try working it in Watts ..

Is the driver ratted to 5W ... If so ..

Fully charged 18650 = 4.2v = about 1.2A or more depending on driver efficiency

2xRCR123A = 8.4v = 600mA or more depending on driver efficiency

2xPrimary = 6v = 830mA or more depending on driver efficiency

:candle:

 

[bandersnatch]

As far as I know, when you put 2 batteries in series, the voltages get added. How does a flashlight that can take 2xRCR123 as well as 1x18650 deal with this voltage difference? This is like 7.2 vs. 3.7. Does it simply run at a higher current, or can it regulate to deal with the voltage difference? I realize this is a total noob question, but I couldn't find the answer anywhere.

Yes, voltages are added. Usually a light that can handle both 2xRCR123 and 18650 run better on 2xRCR123, in that they maintain their regulation longer and are slightly brighter. I use only 18650s, so I prefer lights that have maximum voltages in the 4.5 range, so that my performance isn't hampered by the manufacturer's attempts to accommodate higher voltage setups.

Also, this is in reference to the Romisen RC-M4 II Q5 on shiningbeam.com, which I'll most likely be buying. I have read that this takes some 18650 batteries, but others don't fit. After looking around, I still do not have a definitive answer on which 18650's fit and which to not. I'd rather not buy some and find that they do not fit. Does anyone know which 18650's fit the RC-M4? If you own the RC-M4, what battery configuration do you use?

I have the RC-M4, it's a nice light. The body is too narrow to handle AW's 2600 batteries, but my Black Trustfires (dealextreme sku.20392) fit fine and seem to run well (and are much cheaper!). Those are the only two types of 18650s that I have, so I can't give a conclusive answer on this one.