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Help with flashlight

MrMatt

Newly Enlightened
Joined
Feb 8, 2005
Messages
12
Ok so I am modding a Coleman/Max 3AAA Flashlight by putting in a 3 Watt UV epidled into it. I purchased a GD Buck/Boost Converter with 2 .15 resistors to give me 650mA Specs for the LED are as follows


Max. wavelength: 398nm
Forward voltage: 3.8V @700mA, 3.6V @500mA, 3.44V @350mA
Lumens: 10-15
Max. current: 700mA
Beam angle: 120-140 degree
Operational temperature: -20C ~ +70C


I wired it as diagrammed below and notice it was EXTREMELY hot (Started melting some of the plastic), I figured that was the nature of the beast and was just planning on putting a heat sink on it however after several minutes of being on (15 or so) the LED began blinking slowly. I was wondering if this is to be expected with how I have it set up or if I calculated something wrong (Wrong Board) or if I wired it wrong...

Thanks for any advice

Matt

Well I can put in attachments so let me try to describe how I wired it. On the back of the board I connected the positive power supply to the center plate and the negative to the thin ring that borders the board.

The LED I connected the Anode to the hole next to the resistors, above where the board says "R1A" then connected the Cathode to the opposite end of the board immediately next to where the board says "C1"
 

dat2zip

Flashlight Enthusiast
Joined
Jan 5, 2002
Messages
3,420
Location
Bay Area
Ok so I am modding a Coleman/Max 3AAA Flashlight by putting in a 3 Watt UV epidled into it. I purchased a GD Buck/Boost Converter with 2 .15 resistors to give me 650mA Specs for the LED are as follows


Max. wavelength: 398nm
Forward voltage: 3.8V @700mA, 3.6V @500mA, 3.44V @350mA
Lumens: 10-15
Max. current: 700mA
Beam angle: 120-140 degree
Operational temperature: -20C ~ +70C


I wired it as diagrammed below and notice it was EXTREMELY hot (Started melting some of the plastic), I figured that was the nature of the beast and was just planning on putting a heat sink on it however after several minutes of being on (15 or so) the LED began blinking slowly. I was wondering if this is to be expected with how I have it set up or if I calculated something wrong (Wrong Board) or if I wired it wrong...

Thanks for any advice

Matt

Well I can put in attachments so let me try to describe how I wired it. On the back of the board I connected the positive power supply to the center plate and the negative to the thin ring that borders the board.

The LED I connected the Anode to the hole next to the resistors, above where the board says "R1A" then connected the Cathode to the opposite end of the board immediately next to where the board says "C1"

Matt,

At 650mA drive current the LED needs to be mounted to a reasonable heat sink of some form.

If you can power the LED as mounted with a power supply you can verify if the LED is mounted correctly to the heat sink and if heat is wicked away properly. If the LED has too much goo underneath it could be more of an insulator than a conductor of heat. With a power supply you can also check the amount of heat radiates out to the body of the light and how hot it gets and how fast it gets hot.

I believe you wired the converter up correctly.

Wayne
 
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