DIY LED brake lights. Need help.

[TitanRev]

Much neat now...nice....I'm very fond of neat DIY job..It makes those half pass six acc shop guys look like newbie when they see our work...

 

[stupidcar]

Much neat now...nice....I'm very fond of neat DIY job..It makes those half pass six acc shop guys look like newbie when they see our work...

Haha thanks. But next time I'm using PCB dy. Aih...
Is it true that resistors and only limit voltage not current or vice versa?

 

[levin818]

Only 12 LEDs?

 

[shiroitenshi]

ohms law. Better use the lm7805 linear regulator. just like the lm7809 suggested in smarttag thread.

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[stupidcar]

ohms law. Better use the lm7805 linear regulator. just like the lm7809 suggested in smarttag thread.

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WALAO EH. Now all the sifu only come out. -.-

 

[shiroitenshi]

i just found out about them in the smartag thread.. i bought them and tried.. they really work! much better than using resistors because can stick a heatsink on them...

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[goohtj]

ohms law. Better use the lm7805 linear regulator. just like the lm7809 suggested in smarttag thread.

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Bro, lm7805 is 5v, how you connect? 2 x leds in serie or 1 x led + resistor per set?

 

[stupidcar]

i just found out about them in the smartag thread.. i bought them and tried.. they really work! much better than using resistors because can stick a heatsink on them...

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Share the whole process please! Make a new thread!

 

[goohtj]

use a lm7809 to produce 9v n connect 3 x 3v leds in series per bank.
led voltage = 3v so 3 x 3led = 9v so no resistor required.

say 12 leds required for your brake light.
you need 4 banks. each bank draws ~25ma current = 100ma.
lm7809 is 1,000ma ~1,500ma loading. or can easily connect up to 40 banks or 120 leds

input voltage = 11v ~ 35v, power consumption = 2watts (14v x 100ma + some powerloss)

advantage of this DIY.
Cheap (RM3) only.
same led brightness when car is started (14v) or not (12v).

option 2. simpless DIY.
connect 5 leds in series per bank. 5 x 3v led= 15v no resistor required.
brightness is lower.

 

[stupidcar]

use a lm7809 to produce 9v n connect 3 x 3v leds in series per bank.
led voltage = 3v so 3 x 3led = 9v so no resistor required.

say 12 leds required for your brake light.
you need 4 banks. each bank draws ~25ma current = 100ma.
lm7809 is 1,000ma ~1,500ma loading. or can easily connect up to 40 banks or 120 leds

input voltage = 11v ~ 35v, power consumption = 2watts (14v x 100ma + some powerloss)

advantage of this DIY.
Cheap (RM3) only.
same led brightness when car is started (14v) or not (12v).

option 2. simpless DIY.
connect 5 leds in series per bank. 5 x 3v led= 15v no resistor required.
brightness is lower.

bro, i am asking the smarttag one.

 

[goohtj]

bro, i am asking the smarttag one.

http://static.rcgroups.net/forums/attachments/7/5/7/6/5/a775496-132-9v-regulator.gif?d=1143243404

 

[vr2turbo]

use a lm7809 to produce 9v n connect 3 x 3v leds in series per bank.
led voltage = 3v so 3 x 3led = 9v so no resistor required.

say 12 leds required for your brake light.
you need 4 banks. each bank draws ~25ma current = 100ma.
lm7809 is 1,000ma ~1,500ma loading. or can easily connect up to 40 banks or 120 leds

input voltage = 11v ~ 35v, power consumption = 2watts (14v x 100ma + some powerloss)

advantage of this DIY.
Cheap (RM3) only.
same led brightness when car is started (14v) or not (12v).

option 2. simpless DIY.
connect 5 leds in series per bank. 5 x 3v led= 15v no resistor required.
brightness is lower.

Did not know you sifu in this....

 

[goohtj]

Did not know you sifu in this....

Bro, me only major in Electronic n Computer..

Btw, where 2 source for good super bright led? tried pasar rd - not ideal.

 

[stupidcar]

Bro, me only major in Electronic n Computer..

Btw, where 2 source for good super bright led? tried pasar rd - not ideal.

Bro, eBay. It is cheap. So far so good.
Just be careful before u chose the buyer, see if their ratings are better than 99.8% or not.
If it's less than that, then see the past 6 months, how many complains they got.

 

[levin818]

http://static.rcgroups.net/forums/attachments/7/5/7/6/5/a775496-132-9v-regulator.gif?d=1143243404

It is not a good idea to drive the LED using this method. A proper way should be controlling the current but not the voltage. Reason why is because LED has a very steep V-I curve. A slight changes in voltages will cause a huge changes in current. If the LED has a low side in forward voltage due to manufacturing batch, then it may end up blowing these LED in a short period of time.

 

[shiroitenshi]

rs online or element14.com

both got branch in malaysia if you want luxeon leds and drivers

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---------- Post added at 01:19 AM ---------- 6 hour anti-bump limit - Previous post was at 01:14 AM ----------

It is not a good idea to drive the LED using this method. A proper way should be controlling the current but not the voltage. Reason why is because LED has a very steep V-I curve. A slight changes in voltages will cause a huge changes in current. If the LED has a low side in forward voltage due to manufacturing batch, then it may end up blowing these LED in a short period of time.

isn't the lm7809 current limited to 1A? Why would it be a problem?

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oh, nvm, i get your point, but easily solvable by not running the leds in series right?, so LM7805/LM7809 + resistors + leds in parallel is workable?

btw stpcar, I used the lm7809 + caps for the smarttag, not LEDs.

 

[artful]

Hi all sifu,

If i need brake light function with my below setting, what type of diode and extra resistor to add??

HPWS-FH00-H4000 Lumileds Superflux LED
Vf : 2.6V(typ)
If　: 70mA(max)
Total LED: 17

turning it on with a resistor in the 12V car (maximum voltage 14.4V) about 50mA.
I'm using 【1W 240Ω】 resistor for each superflux LED. Below is the diagram

 

[goohtj]

Hi all sifu,

If i need brake light function with my below setting, what type of diode and extra resistor to add??

HPWS-FH00-H4000 Lumileds Superflux LED
Vf : 2.6V(typ)
If　: 70mA(max)
Total LED: 17

turning it on with a resistor in the 12V car (maximum voltage 14.4V) about 50mA.
I'm using 【1W 240Ω】 resistor for each superflux LED. Below is the diagram

your is a single led per bank - alot of power loss

why not connect 5 leds in serie per bank
5 x 2.6v = 13v
could add 28ohm resistor ( 14.4v-13v =1.4v / 50ma = 28ohm)

note: this brings up to 15 leds or 20 leds ..

 

[thilak79]

Can someone help me to sort my led brake light issue? I see some experts around here would really appreciate if someone could sort it out.

 

[levin818]

... so LM7805/LM7809 + resistors + leds in parallel is workable?...

Yes connection in this way is better! The LED brightness will not affected by the variation of battery voltage. But the max output current is limited by the type of Voltage Regulator being use.

---------- Post added at 11:57 PM ---------- 6 hour anti-bump limit - Previous post was at 11:53 PM ----------

I personally find this this page is quite informative. It has a simple resistor current control circuit to a more complicated MOSFET constant current driver. Great for those who want to DIY.
http://www.pcbheaven.com/userpages/LED_driving_and_controlling_methods/

---------- Post added 08-12-2013 at 12:00 AM ---------- 6 hour anti-bump limit - Previous post was 08-11-2013 at 11:57 PM ----------

Can someone help me to sort my led brake light issue? I see some experts around here would really appreciate if someone could sort it out.

Is it from 8-series :O
Yes it can be recover. But the plastic cover might need to cut open in order to reach the LEDs inside.