help for more power from this circuit

[HackoBoy]

hello
i build this circuit
http://img368.imageshack.us/my.php?image=ledheadlightcircuitxz8.jpg

but , i change some elemenst
1: i use 40 led ( each led = 20 000 mcd with 15 degree ) but i can turn max 60 led .
2: instead PN2907 i use BD242 put on the radiator
3: i use for this thime 6 alkaline battey AA , but after time i use 6 cell Ni-Mh Battery
i show how a leds
http://img232.imageshack.us/my.php?image=leddp1.jpg

i need help for change parameters of elements for more power
i use for this moment Pot = ( R4 ) for regulate ampere in Led for this moment 400 mA , but when i give more ampere about 800 mA something about i see my leds how blink - like a stroboscope - but when i turn about 400 mA i see my leds light normal and don`t blink like a stroboscope.

or i need to build another schematic ?

 

[Gunner12]

First off I don't know much about electronics so I can't answer you questions.

Most 5mm white LEDs are only meant to take 20 mA each. I don't know much about electronics but from your first picture it looks like you have 10 LEDs, and if it is 400 mA to 5 strings of 2 LEDs in series, each LED is reciving 80 mA. When the LEDs are driven way too hard, they sometime strobe. It could also be another part in the circuit.

I'd recommend you to look into high power LEDs. Most 5mm LEDs are 3-4 lumen at normal drive current, a high power one can hit over 200 lumen each and that is before their limit(usually 1000 mA). They do require heasinking unless at very low currents though(low for the LED). They(high power LEDs) don't come with a built in optic though like most 5mm LEDs. The high power LEDs usually use a reflector or an external optic to focas and manipulate the light.

The Cree(company name) XR-E(model) Q5(flux bin) hits 200 lumen at around 800 mA at around 3.5v.

You could probably buy a P60 type drop-in like this one, usually used to upgrade P60 accepting type lights like the Surefire 6P, and wire it with a switch to the battereis and it can be a bike light. I've seen a few of those and you might not need too much of a heatsink depending on how fast you ride.

:welcome: