LED Light wire harness question
 

Based on these specs can anyone tell me what resistor is needed to run 4 bulbs on 3s or 12 volts?

SPECIFICATIONS:
Source Material:InGaN !
Emitting Colour:10MM POWER WHITE 1W LED
LENS Type:Water clear
Color Temperature: --
Luminous Intensity-MCD: Typ: 390,000 mcd
Reverse Voltage:5.0 V
DC Forward Voltage: Typical:
DC Forward Current:300mA
Viewing Angle:40 degree
Lead Soldering Temp:260°C for 5 seconds
http://i628.photobucket.com/albums/u...ps856f8f0a.jpg

Re: LED Light wire harness question
 

So by "typical" Vfd, I think they mean since it's a white LED, it's 3V. Also confirmed by the 1watt rating 1W/300mA =3.3V
3S = 12.6V
12.6v - 3vLED = 9.6V across the resistor / per bulb
9.6V / 300mA = 32ohms

To size it, I2*R
300mA * 300mA * 32ohms = 2.88watts.

Your better to run 2 bulbs in series on a string. Less wasted energy
Then you need 22ohms @ 2 watts.

Either way, you need a 4watt resistor per string so they don't melt everything around them.

Re: LED Light wire harness question
 

I will use 2 resistors then? Using the 2 bulbs in series? Thank you.
Or a resistor per bulb?

Re: LED Light wire harness question
 

I just ordered 20 of the 22 ohm 2w resistors 1.98 free shipping ebay is awesome!

Re: LED Light wire harness question
 

While your at it grab a couple 22ohm 4watts too. Your dissapation is 2watts so they may get pretty warm at rating

Re: LED Light wire harness question
 

FEATURES:
New !
In excellent condition
Long lasting (over 100000hours)
Low Power Consumption
I.C. Compatible
Intensely Bright
SPECIFICATIONS:
Source Material:InGaN !
Emitting Colour:10MM POWER WHITE 1W LED
LENS Type:Water clear
Color Temperature: --
Luminous Intensity-MCD: Typ: 390,000 mcd
Reverse Voltage:5.0 V
DC Forward Voltage: Typical:
DC Forward Current:300mA
Viewing Angle:40 degree
Lead Soldering Temp:260°C for 5 seconds
Absolute Maximum Rating (Ta = 250C)



PARAMETER
MAXIMUM RATING
UNITS
DC Forward Current
300
mA
Peak Pulse Forward Current (1)
450
mA
Avg. Forward Current (Pulse Operation)
300
mA
Operating Temperature
-40 to +100
0C
Storage Temperature
-40 to +120
0C
Lead Soldering Temperature
2600C for 6 seconds
(1.0mm or 0.63 inch from Body)

(1) Pulse conditions of 1/10 duty and 0.1msec width



Electro-optical Characteristics (Ta = 250C)



PARAMETER
SYMBOL
CONDITIONS
MIN.
TYP.
MAX.
UNIT
Forward Voltage
VF
IF = 300mA
3.0
3.4
3.6
V
Reverse Voltage
VR
IR = 300mA
-
5
-
V
Dominant Wavelength
lD
IF = 300mA
-
X=0.31 Y=0.32
-
-
Viewing Angle
2q1/2
IF = 300mA

40

Deg.
Luminous Intensity
IV
IF = 300mA
-
390,000
-
mcd