Dare I Direct-Drive a Q2H with 3 x AA NiMH...

...or is an H-bin simply too low a Vf to tolerate that kind of overdrive?

Thanks in advance - John

maybe.
how good of a heatsink will the host provide?

I'd do it with proper heat sinking. I've done a Q3J on 3D's with no probs, but the nimh cells might get you more current than the alkalines I use. Just do it and take a reading. If it's too hot, use a little resistance.

Well, I'm lapping an electrical grade copper sink to a Brinkmann 3AA, and also lapping the emitter slug to the copper slug. I'll probably use straight AA epoxy and some light, even pressure while it cures...

Thanks - John

[ QUOTE ]
Chop said:
I'd do it with proper heat sinking. I've done a Q3J on 3D's with no probs, but the nimh cells might get you more current than the alkalines I use. Just do it and take a reading. If it's too hot, use a little resistance.

[/ QUOTE ]

wouldent the LED pull less current because the NIMH are providing less voltage? I know they are capable of delivering more current, but I know an LED at lower voltage will Pull less current...??? /ubbthreads/images/graemlins/thinking.gif

Consider the high internal resistance of alkalines resulting in larger voltage drop under high current loads.

NiMH with lower internal resistance drops less voltage under load, resulting in higher voltage and current to the LED.

Since the Q2H's are affordable enough and they're easy enough to replace if done carefully, I'm going to risk it just to see what happens.

Should be a real thrower with a carefully cut smooth reflector... /ubbthreads/images/graemlins/grin.gif

Thanks for the input - John

Fresh off the charger I would let the nimhs sit overnight before hitting the poor little 1-watter with all that current...just to be safe.

Hi Mr. B-

Yes, that is my plan. Don't want to actually *try* to fry the little bugger right off the bat...I'll let the initial peak charge dissipate before using them.

Say, have I missed seeing the Brink 3AA done with a Lux III? Ya know, I do have a couple of LIII's laying around...hummm. Not sure if I could drive one sufficiently unless I use the lithuim AA's, though.

Thanks - John

Yeah three fresh alks in a 3AA Direct Drive setup will push near an amp through, which will make for very nice (and still relatively safe) brightness from a LuxIII. If I recall correctly I did one using a TWOJ and got 1800+ lux with a Fraen LP.

Cool - Thanks Charlie!