DIY LED brake lights. Need help.

[TitanRev]

stupidcar, the diagram levin showed you is the same like mine. I think you will get what he mean soon...

 

[stupidcar]

stupidcar, the diagram levin showed you is the same like mine. I think you will get what he mean soon...

That's what i did too. So I'm a bit confused here.

 

[levin818]

From your picture, you are putting the LEDs in parallel.

---------- Post added at 01:01 AM ---------- 6 hour anti-bump limit - Previous post was at 12:59 AM ----------

Would suggest you just copy exactly what TitanRev does. Save your time.

 

[levin818]

Parallel connection:

 

[stupidcar]

From your picture, you are putting the LEDs in parallel.

---------- Post added at 01:01 AM ---------- 6 hour anti-bump limit - Previous post was at 12:59 AM ----------

Would suggest you just copy exactly what TitanRev does. Save your time.

I did 4 leds in series to a parallel 12V source.

 

[levin818]

Ok can you please take a closer picture and show it here once more?

 

[stupidcar]

Ok can you please take a closer picture and show it here once more?

I'm gonna go swap my 1/4W resistor with 2W then I'm done. 1 step closer!
By using this http://led.linear1.org/led.wiz ,
13V source, 2.8 forward V and 20mA, it came out with 4 Leds to a 100ohm 1/4W resistor.
Why is the wizard giving me that answer ah?

This is my spec sheet btw. No wattage value. I don't know how to count so I rely on calculators, manatau its wrong.

 

[stupidcar]

Anyone?

 

[TitanRev]

stupidcar, I can't see your image la...also you no need to 100% follow the site give you the W.

 

[levin818]

I'm gonna go swap my 1/4W resistor with 2W then I'm done. 1 step closer!
By using this LED series parallel array wizard ,
13V source, 2.8 forward V and 20mA, it came out with 4 Leds to a 100ohm 1/4W resistor.
Why is the wizard giving me that answer ah?
This is my spec sheet btw. No wattage value. I don't know how to count so I rely on calculators, manatau its wrong.

If you follow the web site suggestion, you can use 100ohm 1/4W resistor.
The reason i suggest you to change it to 2W is because i assumed you connect the LED in parallel.

 

[stupidcar]

stupidcar, I can't see your image la...also you no need to 100% follow the site give you the W.

If you follow the web site suggestion, you can use 100ohm 1/4W resistor.
The reason i suggest you to change it to 2W is because i assumed you connect the LED in parallel.

Guys, I reuploaded the pics. BTW, I used the same method as the wizard showed me ma.

 

[TitanRev]

Stupidcar, you read the website suggestion carefully.

Pick from website
the wizard thinks 1/4W resistors are fine for your application

Also pick from the ? mark
Resistor power rating
The wizard uses your drive current to calculate the power dissipated in the array resistors. Standard resistors are available in 1/8W, 1/4W, 1/2W and 1W, and some values are available above that. The wizard picks a resistor wattage for you based on the guideline of operating at less than 60% of the rated power.

W in resistor is the power rating of the resistor. In other words, after you have designed your circuit, you look at the selected resistors, and you calculate the power dissipated (I) Power = current x voltage (P=V/R, or P= V2 /R or P= I2 x R- you MUST select resistors with a power rating that exceeds the result.

You can use this to calculate the resistor Wattage
20mA x 2.8 = 0.056 watt of power required. This is 1 LED.

From the picture can see you resistor all black already..overheated. This means your resistor is not enough. You give me your intended LED nos. I work out the wiring diagram for you.

 

[stupidcar]

Stupidcar, you read the website suggestion carefully.

Pick from website
the wizard thinks 1/4W resistors are fine for your application

Also pick from the ? mark
Resistor power rating
The wizard uses your drive current to calculate the power dissipated in the array resistors. Standard resistors are available in 1/8W, 1/4W, 1/2W and 1W, and some values are available above that. The wizard picks a resistor wattage for you based on the guideline of operating at less than 60% of the rated power.

W in resistor is the power rating of the resistor. In other words, after you have designed your circuit, you look at the selected resistors, and you calculate the power dissipated (I) Power = current x voltage (P=V/R, or P= V2 /R or P= I2 x R- you MUST select resistors with a power rating that exceeds the result.

Will go home and count it up! Thanks again.

 

[TitanRev]

Stupidcar, I just worked out a wiring diagram for you. You can test it out. My spec is like below. I use 14V as engine started the Voltage is about that range. You can use 100 Ohm resistor @ 1W. Calculated actual Ohm is 82 but I go higher for safety. You can try 110 Ohm also but LED less bright.
Vs = 14V
LED = 3v
Current = 25mA

 

[stupidcar]

Stupidcar, I just worked out a wiring diagram for you. You can test it out. My spec is like below. I use 14V as engine started the Voltage is about that range. You can use 100 Ohm resistor @ 1W. Calculated actual Ohm is 82 but I go higher for safety. You can try 110 Ohm also but LED less bright.
Vs = 14V
LED = 3v
Current = 25mA

Dude! You don't have to... ahaha paiseh. Thing is my specs is 20mA.
I don't mind my lights to be dimmed abit. Its still an ultrabright with 4000-5000mcd and also 120-140 degree. Wouldn't lose too much brightness I guess.