Direct drive of Seoul P4 without resistor - advice needed

lexina

Enlightened
Joined
Jul 3, 2005
Messages
782
I am really happy today because I completed my first real Mag led mod using a cut-down Mag1C (driven by 1 18650), a Seoul P4 USWOI and one of Litemania's wonderful heatsinks and following 3rd shift's excellent step-by-step instructions. :)

I just have one question. As per 3rd shift's instructions, I was supposed to incorporate a 1 ohm resistor. However, this made the light extremely dim (I laterfigured out that the shop had given me a 1,000 ohm resistor!) and I ended up leaving out the resistor. Without the resistor, I measured the current at around 880 mA which is within the 1A tolerance of the Seoul. My question is - do I need to worry about my supply voltage (4.2V fresh off the charger) being higher than the Vf of the P4 (rated at 3.25-3.5V)? Will this damage the led?

Thanks for any advice.
 
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MatajumotorS

Enlightened
Joined
Oct 24, 2006
Messages
263
Location
Latvia
You will not get higer than 1,2A ad fresh from charger Li-On and for short time. There is no need to worry about.
 

Lighthouse one

Flashlight Enthusiast
Joined
May 4, 2006
Messages
1,237
Location
Ephrata, Pa
Translation: no problem....The battery only is at max power for a short time- then settles quickly to a bit under 4.0 volts. Almost any high power Led can handle 4.0 volts. Might only give your 25 years instead of 50...big deal!
 
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