Circuit board, P4s, help?

Drewfus2101

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Jul 16, 2007
Messages
341
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So on my first big modding, I decided to take an Advance Auto Parts 3W Luxeon and swap out the Lux for a P4. Worked great, much brighter.

Next step I got some 18650's (it takes 2 Cs) and used rubber tubing as a spacer and a bolt with washers for the length. Put it in, little brighter. BUT, as it ran for around 30 seconds, the light would go from nice neutral white to a bluish tint and be a little dimmer. I checked the current at the tailcap, and it was running right at 1.25 amps. So, I pulled out that battery and left the Cs in there.

Fast forward to today, and I got some 5 mode circuit boards from DX at around $5 each. SKU 6190. Got one in and it works ok. BUT, its also not much brighter than with the Cs. Checked the current at the tailcap on high, and its right at 600mA. Voltage at the emitter is 3.3V. AND, its doing the same color change thing as before. After about 30 seconds, the light turns bluish and dims.

What gives? Is it the P4s? Do they not like anything over 3 volts? I thought their data sheet said ~3.5V or so. Figured I'd be ok using the 18650s with a board designed to take in up to 4.5V. Did I wire it wrong? The board didn't come with any pics or anything. On the bottom of the board, where its to two concentric circles, I used the inside at the + from the battery, and outside as the - from the battery. I had to attach the wires to the top myself, but they were labeled and ran them to the emitter.
 

Yenster

Newly Enlightened
Joined
Sep 12, 2007
Messages
172
Location
Texas, USA
Blue is not good. Did you have adequate heatsinking when you first ran it on the 18650 at 1.25A? I wonder is the LED may be damaged.
 

legtu

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Joined
May 19, 2004
Messages
516
Location
PH
ssc LEDs are known for their tint shift when its overheating. i suggest checking thoroughly if the led is making good contact with heat sink. :)
 
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