Hey all,
I've just completed my latest conversion project and want to share several photos:
I have started with old Scuba Light Idra torch that had halogen light emitter. Battery and switch on PCB were dead, so they went straight to the bin...
It has very odd shape so my battery choices were limited. I decided to use the same configuration that was in the original torch - 5 x Sub-C batteries in a series. Unfortunately, batteries that I have used are few years old, so they might have their capacity decrease from original 2800 mAh. I am using Panasonic HHR300SCP. Grey lines on top of pack are used as a handle to remove the pack.
Torch is operated with a magnetic switch. I am using hall effect sensor to turn torch on and off.
I am using 4x OSRAM Golden Dragon LEDs with Ledl spot lens. Leds are driven at 500mA.
My LED driver is based on a LM3410 chip by TI (ex. National Semi). ON-OFF function is provided by LTC2950 on-off controller. Since this is home-brew single sided PCB, I had to use a bit of Kynar wire to have nice and big undivided ground plane. There are 2 separate power rails - one is Vbatt that is used for power stage and another 3,3V power rail based on poor man's stabilizer (zenner and resistor) for powering driver and on-off controller.
OD of aluminum ring is 50mm. There's still a lot of PCB real estate available for additional features.
Driver is ready for assembly
LED head and driver assembled - side view:
LED head - back view with power contacts and hall effect sensor visible:
Battery in a case:
4 leds have forward voltage drop of 12V when running at 500mA. At the time of testing battery pack had an output voltage of 6.3V and driver was drawing 1,08A from it. This gives efficiency of 86%. I'm happy with this value given the fact that this driver has FET integrated.
Now once this project is finished*, I am thinking about upgrades. Once I have Li-ion charger, I will swap out battery pack to 2 Li-ion cells. This should give higher input voltage and further increase efficiency a bit. Next step will be LED head with 3 XM-L EZW LEDs and Ledl CUTE spot lens.
* - this was my longest project so far with 7 revisions from driver test board to final driver.... Some just did not work, some died because of my carelessness...
I've just completed my latest conversion project and want to share several photos:
I have started with old Scuba Light Idra torch that had halogen light emitter. Battery and switch on PCB were dead, so they went straight to the bin...
It has very odd shape so my battery choices were limited. I decided to use the same configuration that was in the original torch - 5 x Sub-C batteries in a series. Unfortunately, batteries that I have used are few years old, so they might have their capacity decrease from original 2800 mAh. I am using Panasonic HHR300SCP. Grey lines on top of pack are used as a handle to remove the pack.
Torch is operated with a magnetic switch. I am using hall effect sensor to turn torch on and off.
I am using 4x OSRAM Golden Dragon LEDs with Ledl spot lens. Leds are driven at 500mA.
My LED driver is based on a LM3410 chip by TI (ex. National Semi). ON-OFF function is provided by LTC2950 on-off controller. Since this is home-brew single sided PCB, I had to use a bit of Kynar wire to have nice and big undivided ground plane. There are 2 separate power rails - one is Vbatt that is used for power stage and another 3,3V power rail based on poor man's stabilizer (zenner and resistor) for powering driver and on-off controller.
OD of aluminum ring is 50mm. There's still a lot of PCB real estate available for additional features.
Driver is ready for assembly
LED head and driver assembled - side view:
LED head - back view with power contacts and hall effect sensor visible:
Battery in a case:
4 leds have forward voltage drop of 12V when running at 500mA. At the time of testing battery pack had an output voltage of 6.3V and driver was drawing 1,08A from it. This gives efficiency of 86%. I'm happy with this value given the fact that this driver has FET integrated.
Now once this project is finished*, I am thinking about upgrades. Once I have Li-ion charger, I will swap out battery pack to 2 Li-ion cells. This should give higher input voltage and further increase efficiency a bit. Next step will be LED head with 3 XM-L EZW LEDs and Ledl CUTE spot lens.
* - this was my longest project so far with 7 revisions from driver test board to final driver.... Some just did not work, some died because of my carelessness...
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