Hey Avro! /ubbthreads/images/graemlins/wink2.gif I've been pimping-out Q3s for myself and some other CPFers for a while now. Haven't used an R123 in any of mine yet, but I've installed plenty of Dorcy 1AAA circuits with no problem. On a regular 123 cell a TYAH star usually generates output that's as bright or brighter than stock, with 50-100% longer runtime than stock and WAY more graceful rundown at the end of battery discharge... I fell asleep one night while testing one, and woke up surprised to find that
8 hours into the elapsed runtime, the thing was STILL producing enough light to navigate easily through my house without tripping... that's no simple task given that I've got three sons, aged 5,3, and 6 months, and the floor is usually a minefield of toys! /ubbthreads/images/graemlins/ooo.gif
Anyway, that's probably not so relevant to you. I do know this, though: according to Doug S (at least I
think it was him), the circuit should be capable of running with up to 4.5V input, so an R123 ought to do fine. I'd be more worried about the output side cooking the LuxIII... but my guess is that TY0L should have no problems at all!
Keep in mind, though, that the output on this circuit is Vf-sensitive, meaning the lower the Vf of the LuxIII, the higher the current flow will be. That makes the mod a little bit of an art... you kinda want to pair the circuit and power source with an emitter that drives as much current as possible through the output on a fresh cell... but not
too much! /ubbthreads/images/graemlins/icon15.gif
Patience is DEFINITELY a virtue here. /ubbthreads/images/graemlins/grin.gif
Tell me about the AM50 vs. CX chips, please... that's new info to me! PM me if you don't want to pollute this thread. For my part, I'll pass along a couple tweaks that Doug S suggested for a little better efficiency at high output levels... first, add a third 10uF capacitor to the empty pads on the board... and second, short out the 1 ohm resistor sitting just above (as in closer to the LED) the inductor. These two tweaks should add several percentage points of efficiency when driving high currents out of the circuit.
Incidentally, for those who are new to the Dorcy 1AAA circuit, one of my favorite mods so far... the one-of-a-kind MilkMite (described in a thread elsewhere on CPF)... is powered by a Dorcy 1AAA circuit... here's a runtime graph...
Your mileage will vary based on 123 vs. R123, the Vf of the emitter, etc., but it's pretty safe to say you'll see MUCH improved runtime characteristics over the stock circuit!
Okay, I'm completely out of control at this point, rambling all over the place. Hope all this crazy info helps folks at least a little! /ubbthreads/images/graemlins/grin.gif