How much brigher does R-CR123 make the QIII

This thread has excellent pics of the QIII with a regular and rechargeable battery. https://www.candlepowerforums.com/posts/1176152#post1176152

The rechargeable is clearly brighter, but I do not know if it is 3.7 or 4.2 volt battery.

Figures are based on peak battery freshness, and are slightly rounded down as I go to adjust for actual sustained voltage with use.

Here are my calculations. CR123 = 3.7v and R-CR123 = 4.2v

((4.2 - 3.7) / 3.7) * 100 = about 13.51% higher voltage.

We know higher voltage makes a bulb brighter, so ignoring the circuit in the QIII for a moment, we can expect about 13% MORE light from the little QIII.
:wow: Now, can anyone measure so we know for sure?


If I recall correctly, someone said the QIII actually emits about 60 lumens.

60 lumens * 13% brighter = 7.8 lumens. Rounding down, we get about 67 lumens.

Looks like we are a lot closer to that 75 lumen rating.

The LED bulb is 3w divided by 4v to get a current draw of 0.75a.

A R-CR123 at 4.2v is rated at 750 ma. Thus giving close to 1 hour of light. Maybe more like 45 minutes of desireable light. If 45 minutes is not a lot of time to you, clamp a binder clip onto a painful part of your body. Your sensation of time will change by 45 seconds. :mecry:

:lolsign:

Tron3, a CR123 is a 3.0 volt non rechargeable primary battery.

A same sized rechargeable lithium-ion cell will state a voltage of 3.6 to 3.7 on the outside of the wrapper. (There are 3.0 volt rechargeables but that's for a different post.)
This 3.6-3.7 volt rechargeable cell will be at 4.1-4.2 volts when fully charged and just removed from the charger. These cells will only be at 4.1 to 4.2 volts for a short time during a normal discharge cycle so it's not really correct to think of them 4.1 to 4.2 volt cells. The largest portion of their discharge cycle will be near 3.6 volts so they are labeled with this voltage.

We see this with other types of batteries also. A fresh D sized alkaline may be more than 1.65 volts but is labeled 1.5 volts because under moderate discharge it's voltage will be at 1.5 volts (or just below)for most of the cell's life.

The stock Q3's output will depend on the bin of the luxeon star it comes with. A T bin will be brighter than a S bin and a U bin brighter than a T bin provided they all have the same forward voltage rating.

A freshly charged 3.6-3.7 volt labeled battery can easily direct drive as much as 1200 milliamps or more into a 3 watt luxeon star that has a forward voltage rating of J, K, or even some of the L rated ones.

Check the specifications for a U bin star and see how many lumens they will output at 1200 milliamps. You will be surprised. Subtract losses for the reflector and the lens and you still get plenty of light coming out of the flashlight.

Getting 100+lumens out of the front end of a Q3 is one of the reasons they are so popular as a mod platform. The mods are easy to do and don't cost a fortune to complete.

Why not build your own 100+ lumen Q3?

Replacing the lens and reflector is not costly and would result in a beamshot that is one more step up compared to just using a rechargeable battery over a normal 3 volt disposable primary cell.

Those are my pics... I would hate to guess at lumen estimations, plus my Q3 is modded with a TW0J star so is likely brighter than most stock Q3s unless you get really lucky but I can put it like this: On a primary 123, the light is maybe 10% brighter than a Fenix, with a larger hotspot but with a slightly narrower spillbeam edge to edge. With the R123, it is a considerable step up. I'd have to guess at least 30% to 50% brighter.

Or said another way, I think with the primary 123, the Q3 is driven to Lux I levels while on the R123 it's driven to Lux III levels. There is no comparison.

My Q3 also has a 2 stage tailcap and maybe the comparison pics on low will show the difference a bit more clearly.

First pic is with a primary 123, bottom pic is with an R123. You aren't so much looking at the brightness, but the difference in brightness. I think these show the difference a bit more clearly but on high, the difference is just as pronounced, just maybe not as easily captured with my camera.

Oh, the cells used here are the MP unprotected 3.7V cells available from forum member AW. I asked the forum which unprotected cells were the best for such use and the consistant reply was the MPs so I went with them.

They come off my charger at about 4.23V. For some reason, one consistantly comes off at 4.23 and the other comes off higher... at about 4.28-4.33. I only use the 4.23 one with the Q3.

LumenHound said:

Tron3, a CR123 is a 3.0 volt non rechargeable primary battery.

A same sized rechargeable lithium-ion cell will state a voltage of 3.6 to 3.7 on the outside of the wrapper. (There are 3.0 volt rechargeables but that's for a different post.)
This 3.6-3.7 volt rechargeable cell will be at 4.1-4.2 volts when fully charged and just removed from the charger. These cells will only be at 4.1 to 4.2 volts for a short time during a normal discharge cycle so it's not really correct to think of them 4.1 to 4.2 volt cells. The largest portion of their discharge cycle will be near 3.6 volts so they are labeled with this voltage.
....

Click to expand...

I know this much, when I measure the voltage on each, they measure as I stated. I also know using 4.2v ones WILL damage or burn out certain electronics. So, what gives?

LumenHound said:

Why not build your own 100+ lumen Q3?

Replacing the lens and reflector is not costly and would result in a beamshot that is one more step up compared to just using a rechargeable battery over a normal 3 volt disposable primary cell.

Click to expand...

How much, and how do I get started? :rock:

Cratz2: What current reading do you get when you remove the tailcap and measure current between the battery and the edge of the battery tube?

Tron3: Start off by getting a Q3 and hope it has a T binned star. It will likely have a less bright S binned star. Nothing wrong with a S binned star, but for max performance you need a T bin as the minimum and prefered would be a U bin.

1) Replace the reflector with a IMS20 reflector and replace the polycarbonate plastic lens with a much clearer and way more scratch resistant mineral crystal. These 2 parts make a very noticeable improvement.

The reflector should only cost about $5.00 and the mineral crystal about the same or less. If you have trouble locating a mineral crystal, you can get one from a watch repair place for a few dollars extra.

There is ample info here on the forums about replacing the reflector and lens. It's not difficult to do.

2) Get a charger and battery for your Q3. Protected cells are much preferred here. The money you save on not buying those regular 3 volt cells adds up quickly.

3) If you are using a S binned star, you need to upgrade to a better star. This will be between $20-$30 depending on your choice of T bin or U bin.
Personally, I'd opt for the U bin if available. Also, lower forward voltage ratings equal longer run time.

4) Improve the heatsink. Chimo's 2 penny idea works well or you can buy an aftermarket copper heatsink designed for the Q3. 2 penny heatsink

Finally: Consider bypassing the old converter circuit in the Q3 totally. It's not needed when using rechargeables and bypassing it means that all of the power of the battery is being used by the luxeon star and none is being wasted by the old converter circuit.

I'm not at home but I'll post the current reading later unless someone else chimes in... But my guess is the star is seeing .7-.8A and still below the 1A 'limit'.

LumenHound said:

Why not build your own 100+ lumen Q3?

Replacing the lens and reflector is not costly and would result in a beamshot that is one more step up compared to just using a rechargeable battery over a normal 3 volt disposable primary cell.

Click to expand...

This will give you a tighter hotspot, but the lumen rating would not change. the only way to change this would be to increase the voltage or replace the luxeon star. (5W?)

Hi Lightmaster.
Your response is 100% correct but the statement regarding the reflector/lens replacement was not meant to be an answer to the question preceeding it. It was meant to be the first step in a upgrade process that would result in a 100+ lumen output Q3.

Try swapping out the original reflector and lens with a mineral crystal lens/IMS20 reflector yourself and see if you think it is a better beam.
Give it a whirl.

Most people who do this upgrade really like the improvement and the fact that the "fidgit factor" on this upgrade is low doesn't hurt either. No soldering involved and instant results. It's an easy way to start down the long and winding flashlight modding trail.

My meter reads .81A on a primary 123 and starts off at 1.48A on the MP R123 fresh off the charger and drops .01A about every three seconds. But if I stop at 1.40A, and leave the meter off for about a minutes, it measures about 1.44.

I know the circuit in the Q3 is widely considered to be painfully ineffecient but is there a concensus on what the effeciency is?

Also, how to I measure current at the star?