Team-BHP - LED lighting in cars

Quote:

Originally Posted by Chipz (Post 1824530)

In my case it was a 3V bulb, a solenoid I made over a blade, speakers, secondary winding of a transformer, and other goods.

That's one complicated stupid experiment... stupid:

Now its time to do some D.I.Y. stuff on my car, I've take 1.5 meter LED Strip.

This weekend you guys are going to enjoy a few pics of nice and Decent L.E.D. install which I am sure many would get tempted for.

Quote:

Originally Posted by shyamhegde (Post 1823297)

I am using a LM317 based constant current circuit to drive the LED. LED's forward voltage is 9+ vols. I am limiting the current to less than 1000ma and my input voltage is 12 volts.

Shuamheged; there is 7809 regulator available in the market. you can do away with the additional components in the LM 317 with that. Just a suggestion. Place a good heat sink. I recommend you bolt the regulator directly to the chasis. it is the best heatsink you can get.

Quote:

Originally Posted by anku94 (Post 1826381)

That's one complicated stupid experiment... stupid:

So much for the mind of a 10 year old :)

Quote:

Originally Posted by Chipz (Post 1826674)

Thanks Chipz. I found easy circuit for constant current source using LM317 than 7809 or 7812.
I will think of using chassis as heatsink instead of aluminium finned ones. But not sure if chassis can conduct heat away from junction as quickly as an aluminium heatsink can do, but the size (of chassis as heatsink) might help.

Quote:

Originally Posted by shyamhegde (Post 1826703)

Just curious to know, how can a 317 be more easy than 7809. 317 needs a feedback and a sensing circuit, whereas 7809 does not require anything, you can add a capacitor if you like. Since your bike has a battery, the voltage is pretty much constant. It is just my opinion.

Chasis will be better if it is not painted and if there is good air circulation. The rectifier of the bike is bolted to the chasis for good head dissipation.

Quote:

Originally Posted by Chipz (Post 1827110)

I am no expert to comment on which one is better, on searching for constant current source circuit I came across LM317 circuits and incidentally i also had the IC with me (for some other project).
Do post or PM me if you have a workable current source circuit (i/p 12V) using 7809/7812. one for 1000 ma.

I thought rectifier is bolted to chassis for grounding. But you must be correct, a largest possible heat sink it is bolted on to :) .

Quote:

Originally Posted by shyamhegde (Post 1827886)

on searching for constant current source circuit I came across LM317 circuits and incidentally i also had the IC with me (for some other project).

I am no expert myself in this regard. I just wanted to know why are you using a constant current source in place of a constant voltage source for just one LED, since your output is 12 V for a 9V LED.

Quote:

Originally Posted by Chipz (Post 1822369)

That is very easy to rectify. You just have to meddle with the flasher circuit some. You can adjust the timer to your need.

Mods can you please merge both these posts together. Thanks.

And how to adjust the timer of flasher circuit. please:tell me as soon as possible as i am currently thinking of making or buying a LED bulb and to Convert my whole bike into an Environmental friendly vehicle.:D

Quote:

Originally Posted by Chipz (Post 1828833)

I am no expert myself in this regard. I just wanted to know why are you using a constant current source in place of a constant voltage source for just one LED, since your output is 12 V for a 9V LED.

In my experience LED needs constant current than constant voltage to keep it running for long. LEDs die mostly due to thermal runaway (i see that especially when resistor is used for limiting current for high wattage LEDs). So I prefer to go with contant current circuit. Even if forward resistance of LED decreases due to junction heat, the current through it will still be limited so that it wont burn itself.
If current is not controlled, junction heat=lower forward voltage = more current = more heat = lower forward voltage and this cycle kill the junction instantly. So even if input voltage is constant, increasing current will cause issue.

Quote:

Originally Posted by iamback (Post 1829430)

It depends on the flasher circuit. I dont know if your flasher even have a circuit, there are some without circuit. Most probably you will have to change the biasing capacitor of the transistor which switches the relay. Just check and tell me

or else you can make a multivibrator to switch the relay with the desired frequency :).

Quote:

Originally Posted by ghpk (Post 1826548)

We are midway through the week, waiting for the pics. You've set high expectations, it better be good:)

yups my Bad, was busy on some pending business work so didn't touched the doors yet.
however i did changed the central console lights(the one with A.C controls and ashtray)
and replaced my old L.E.D. Lights with L.E.D. Strips.

Pics are on this thread

I've planned a Relay based circuit for Door safety lights and I'll keep you guys posted with progress soon.

Quote:

Originally Posted by iamback (Post 1829430)

Seems you would need these flashers to Control the L.E.D. Speed as its due to Less Load they would blink fast.
Check this

I need your help guys,

Where in Mumbai do you purchase the loose/single Rs.1 LED from ?
I tried House of LED at Lamington rd, but that uninterested guy sitting at the counter said minimum 100 pcs and that to at Rs.1.5/led.
I don't mind the cost, but 100 pcs is too many. plus where to get the 100ohms resistor from?
Please share some LED shop name and address in Mumbai.

UM

I've posted this many times now...

using 100 ohm resistor will not give prolonged life to L.E.D.'s use at-least 220 ohm for best results as during engine run, Voltage can Rise upto 14.4 volts in some/most cars and your 100ohm resistor would just blow your L.E.D.'s with this extra needed for battery charging.