Q-III: to DD or to Dorcy?

Hi folx, I'm trying to decide between directly-driving my Q-III or sticking a Docry AAA driver into it. What are the general comparisons or suggestions between these two? (What I want to do, here, is to improve efficiency over the stock driver.)

I am interested in the general pros & cons, but my specific application is as follers: The Vf is (or will be, when it arrives from eTendue) K, and I use Battery Station's protected Li-ion rcr123a. Oh, also I should mention the two-stage tail-cap from Goldserve (I don't know the resistence yet, but it could be changed if needed.)

As I understand things so far, one advantage of the Dorcy driver would be that a 3V primary cell would work, should I ever need to use one of those...

What are the other considerations? "Well, what is your objective?" My objective is best use of the battery's energy <least loss>. The straight wire is of course the most efficient, BUT what I do not know is whether runtime would actually be compromised in a DD arrangement, because as soon as the battery's voltage drops below the LED's Vf, I'm afraid current would then cease to flow, whereas a regulation circuit would continue to run the light. Is this correct or incorrect? Or, is a straight wire actually NOT the most efficient, if it happens to turn out that the battery's internal resistance is so low that an additional current-limiting resistor is needed? (Is it going to turn out that way?)

Thanks,
-Ben

If you can afford $1 for each battery change (and that your usage is not like 1 battery change each day) .... for a Primary battery... then go in for a Dorcy AAA Circuit ....

Else.. use protected Li-Ion ... and DD it... (to a TWOK, TWOJ, TWOH etc...) it(TWOK) gives about 50 minutes of constant light.....for a QIII-DD-Li-Ion setup

Initial Investment is about $10 - $15 for the Charger & Batteries... and rest is virtually free for More than a year or two ... given that you will use about 100 minutes each day.. and charging battery everyday... !...

You can see a Q3 DD-TWOJ-R123 runtime in this thread. It is flat enough that you will not notice any decrease in brightness for the first 35 minutes.

If you can live without CR123s, go DD and instead spend your money in a good Q3 copper heatsink, like te ones that ViReN sells.

The runtime plot looks good, and has sold me on the DD approach (and ViReN's copper heatsink), since I can live without CR123s, and since this does appear to be the most efficient way. I'll post an update on how it works out, after the parts arrive.

Thanks for the tips!

It might still run on primaries in a DD setup. It won't be nearly as bright, but it should run.

Yes it runs, in my TWOJ it draws only 100ma at full load, and will give 400 lux initially, but soon will dimm to less than 100 lux, probably during days. Compare that to the up to 1800 lux with the R123.

In a luxeon with a higher Vf it will be worst.

Hey how safe is it to use Protected R123 in a Q-III with a VF K Bin and its original circuit? I am not sure I want to DD mine as I do like having the disposable option if I am out camping for a week or more but I also do want to use some rechargables with it. Any thoughts? Should I still change the heatsink to copper? Or would stock be ok? and Can the original circuit handle a R123 at fully charged 4.2 Volt? Thanks Guys /ubbthreads/images/graemlins/smile.gif

I replace with nexgen500 driver from dat2zip . It work very well and give long runtime with good brightness.

Mike, it should be fine. The R123 dramatically increases brightness. I get 44 minutes with a TYOK and batterystation R123, only a 1 minute drop from the runtime with the stock SX1J. My friend who posts here as Robocop has the exact same setup, and we got 41 minutes from his, so there may be a little variation between individual LEDs and batteries.
No noticeable drop in brightness right up to the end when the battery's protection cuts it off.
The runtime/(rapidly dropping)brightness charts I've seen for DD give me no desire to perform such a mod.
I've bought the mineral glass lens, replaced the reflector with a 20mm IMS, and got the 2AA and Pila 168S extenders, so I'm obviously not averse to making changes to the light, but it transmits heat readily to the body(and even the tailcap) and I'm happy with the runtime, so I have no plans to upgrade either the circuit board or the heatsinking.
That's not to dissuade anyone from making those changes, just saying I'm not going to do it, personally.

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Mike723 said:
Hey how safe is it to use Protected R123 in a Q-III with a VF K Bin and its original circuit? I am not sure I want to DD mine as I do like having the disposable option if I am out camping for a week or more but I also do want to use some rechargables with it. Any thoughts? Should I still change the heatsink to copper? Or would stock be ok? and Can the original circuit handle a R123 at fully charged 4.2 Volt? Thanks Guys /ubbthreads/images/graemlins/smile.gif

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Yes, You can use Protected R123 Cell in the Q-III. If you want to make good Heat Conduction, you can use my $7 (Shipped) Copper Heat Sinks...

It's Simple to Mod the Light...

Just click on my signature... to know more.

What about unprotected? How much of a difference is there? Are unprotected really that risky?

I am using unprotected R123.

One of the problem of unprotected is that if you overdischarge them you can either destroy o degrade the battery. However according to my own tests in a DD (at least for a TWOJ) the light will go very dimm during hours before reaching a damaging voltage. So you will know when is time to recharge with a very wide margin.

However unprotected cells have other risks: in this case basically overcharge (I forgot one on the charger overnight and came out at 4.5v) or shortcut with results ranging from cell degradation to fire or explosion.

If you have unprotected cells you can use them with care. If you have to buy them, buy protected ones.

You can buy Protected Cells at a low cost... from AW.... http://www.candlepowerforums.com/ubbthreads/showflat.php?Number=962058&fpart=all

Thanks bought some protected ones from batterystation and am going to use them in a Nano Charger. From what I read they should work fine just no guarentees from the store that it wont blow up. Anyone have any bad experience with these protected ones in a Nano or good experiences?

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Galiphrey said:
I'll post an update on how it works out, after the parts arrive.

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-just thought I'd give an update, since I said I would: I received ViReN's Cu heatsinc and slapped it into my HA Q-III. I used Arctic Silver between the star and heatsinc, as well as on the sides of the heatsinc, just in case it wanted encouragement in that direction, too...

Well, it works great!! It's very bright, and long-running, with good thermal conduction. I like the discharge curve--I find it much more useful than the original, especially when using the protected LiIons. So, this is exactly what I was aiming for. I guess my TX0K may be towards the lower end of the K range, because even a regular CR123a cell lights it up pretty well. (I did solder a wire between the ends of the spring in the tailcap, just because that half an ohm bugged me.)

I stuck an IMS 20mm reflector in there, too, which really made a big improvement. Also, I changed the second stage from 5 ohms to 10 ohms, because the whole thing is so bright, now, that even the second stage was too bright for the occasions that I wanted just a little light.

SO, I am now a very happy HA-DD-TX0K-CuHeatsinc-glassLens-20IMS-twoStage QIII carrier. /ubbthreads/images/graemlins/yellowlaugh.gif

Great Mod ...

You can even try the POP2G .... will give you a uC Control /ubbthreads/images/graemlins/smile.gif