Hi,
Thought it was time to post my little project here. The flashlight has been used frequently for a year or so, so I know it works well.
I bough a cheap LED flashlight. The original LED are relatively weak (5W or so) but even with that power, the big reflector throws the beam pretty far. However, enough isn't enough for me, so I modified it with something better - well better isn't allways a good thing, but anyways...
This flashlight has a 4V lead battery (Approx 4.5V fully charged). Capacity of approx 6Ah (factory rated). Perfect for a 30W SST-90 LED
What about the LED-driver? Well, I made it simple. In series with the LED I put a small coil which has an internal resistance of approx 0.09 Ohm. That would limit the voltage to approx 3.7V over the LED with a draw og approx 9 amps.
I know the coil probalby would generate a small voltage spike when I turn the light off (Due to the break down of magnetic field around the coil), but the inductance is very very low so it isn't a problem. As said above, the flashlight has worked great for a year or so.
The original LED was surface mounted on the metal reflector. Some additional aluminium discs for even better cooling. I did the same with the SST-90 LED.
I replaced the original switch with one that handles more current. The small board you see in the picture is disabled (not in use anymore). That board also have a chip which controlled the orange blinking LEDs (Removed those LEDs).
I hope you enjoy the pictures. I will add some night-pictures later where I compare this flashlight with the headlighs from my car (I only need to find a USB cable that fits in my Olympus camera). The present pictures was taken with a cellphone...
Coil (resistor) closeup.
Coil (resistor) at the left, switch at the right. Aluminium discs fixed on the reflector.
SST-90 closeup
Mounted SST-90
Reflector diameter @ 130mm
Flashlight housing
Beam at 0.5 meter
Beam at 5 meter.
New switch
The battery. Lead, 4V.
Thought it was time to post my little project here. The flashlight has been used frequently for a year or so, so I know it works well.
I bough a cheap LED flashlight. The original LED are relatively weak (5W or so) but even with that power, the big reflector throws the beam pretty far. However, enough isn't enough for me, so I modified it with something better - well better isn't allways a good thing, but anyways...
This flashlight has a 4V lead battery (Approx 4.5V fully charged). Capacity of approx 6Ah (factory rated). Perfect for a 30W SST-90 LED
What about the LED-driver? Well, I made it simple. In series with the LED I put a small coil which has an internal resistance of approx 0.09 Ohm. That would limit the voltage to approx 3.7V over the LED with a draw og approx 9 amps.
I know the coil probalby would generate a small voltage spike when I turn the light off (Due to the break down of magnetic field around the coil), but the inductance is very very low so it isn't a problem. As said above, the flashlight has worked great for a year or so.
The original LED was surface mounted on the metal reflector. Some additional aluminium discs for even better cooling. I did the same with the SST-90 LED.
I replaced the original switch with one that handles more current. The small board you see in the picture is disabled (not in use anymore). That board also have a chip which controlled the orange blinking LEDs (Removed those LEDs).
I hope you enjoy the pictures. I will add some night-pictures later where I compare this flashlight with the headlighs from my car (I only need to find a USB cable that fits in my Olympus camera). The present pictures was taken with a cellphone...
Coil (resistor) closeup.
Coil (resistor) at the left, switch at the right. Aluminium discs fixed on the reflector.
SST-90 closeup
Mounted SST-90
Reflector diameter @ 130mm
Flashlight housing
Beam at 0.5 meter
Beam at 5 meter.
New switch
The battery. Lead, 4V.
