[shyamhegde]

I am in search of a 20 Watts LED (Star type, like the one Edison makes). Any help to find a place where i can get them (looking for 2 or 3 LEDs only) is appreciated.

At Bangalore, OM Electronics, SP Road has 10 Watts and he says 20W will take a while.

[iamback]

Originally Posted by shyamhegde

I am in search of a 20 Watts LED (Star type, like the one Edison makes). Any help to find a place where i can get them (looking for 2 or 3 LEDs only) is appreciated.

At Bangalore, OM Electronics, SP Road has 10 Watts and he says 20W will take a while.

These types of LED's are available on ebay.com at about Rs.1000 ($20) and takes about 25 days to receive it from the seller as most of the sellers are from china and ships through hongkong post.

I will suggest you to wait until the OM Electronics get it and buy from him as it becomes good if in future you will have any problem you can go and solve. Which is not possible if brought from ebay.com.

[ghpk]

Originally Posted by shyamhegde

I am in search of a 20 Watts LED (Star type, like the one Edison makes). Any help to find a place where i can get them (looking for 2 or 3 LEDs only) is appreciated.

At Bangalore, OM Electronics, SP Road has 10 Watts and he says 20W will take a while.

I am quite sure, they are not yet available in India.
however these L.E.D.s would need a Cooling procedure, as it would get instantly blow up if used without a proper heatsink.
Its something similar like if you run computer CPU without a heatsink.

I've purchased a new POLY-WATT POWER LED which is Big, bright and comes @ Rs.75/each in wholesale from local provider.
will post the pic tonight.

[Chipz]

Originally Posted by iamback

Do remember to send me your suggestions and comments.

I am back; That is good work. Some suggestions;
1. You have bent the legs of the led right on the name plate (If that is what I can see from the picture quality). If the paint of the number plate goes, it will short the legs. Place an insulation there.
2. The focus of the led is not right. The focus is all on the top side. You should place the leds at a distance from the number plate and then bend the legs or you should use a reflector.
3. The legs of the led gets rusted easily in open air and rain. You should cover it tightly with plastic tubing.
4. The wiring, soldering, and the insulation on the back is not long lasting, Place inside a cabinet if possible.

What is the value of the resistors used. Is it 0.5 watt or 0.25 watt.

Any plan of changing your indicator bulbs to leds.

[iamback]

Originally Posted by Chipz

I am back; That is good work. Some suggestions;
1. You have bent the legs of the led right on the name plate (If that is what I can see from the picture quality). If the paint of the number plate goes, it will short the legs. Place an insulation there.
2. The focus of the led is not right. The focus is all on the top side. You should place the leds at a distance from the number plate and then bend the legs or you should use a reflector.
3. The legs of the led gets rusted easily in open air and rain. You should cover it tightly with plastic tubing.
4. The wiring, soldering, and the insulation on the back is not long lasting, Place inside a cabinet if possible.

What is the value of the resistors used. Is it 0.5 watt or 0.25 watt.

Any plan of changing your indicator bulbs to leds.

Thanks for your suggestion.

The value of Resistor is 470 ohm +/- 5% tolerance and 1/4 W i.e. 0.25 W.

Thinking of making a LED indicator bulb. There is big problem of LED when used as indicator. As the led consume so less power that the Indicator flasher speed increase automatically. Due to this the blinking speed of indicator increases.

[shyamhegde]

Originally Posted by iamback

These types of LED's are available on ebay.com at about Rs.1000 ($20) and takes about 25 days to receive it from the seller as most of the sellers are from china and ships through hongkong post.

I will suggest you to wait until the OM Electronics get it and buy from him as it becomes good if in future you will have any problem you can go and solve. Which is not possible if brought from ebay.com.

Let me check with OM Electronics this weekend again and try to know ETA for the same.

Originally Posted by ghpk

I am quite sure, they are not yet available in India.
however these L.E.D.s would need a Cooling procedure, as it would get instantly blow up if used without a proper heatsink.
Its something similar like if you run computer CPU without a heatsink.

I've purchased a new POLY-WATT POWER LED which is Big, bright and comes @ Rs.75/each in wholesale from local provider.
will post the pic tonight.

Thanks ghpk for the suggestion. I have a constant current source circuit to power the LED and also have a heat sink plan for thermal management up to the extent. I would not run the LED at its max to begin with , to keep the LED junction away from thermal runaway condition. I already have built a running 10 Watts LED prototype. That has given some useful experience.
BTW, why do you think they wouldn't be available in India?
I guess LED house (Lamington Road?) in Mumbai should have them. Anyone who knows this place?
OM guy in blr has 10 Watts but not yet 20W.

[ghpk]

Here's the Poly-watt LED i recently purchased.



and



can anyone tell how much 10W LED Cost, and can the OM guy of BLR send it when made a pre-payment.

[anku94]

I've got a question. Why do we need resistors in the circuit ?

[Chipz]

Originally Posted by anku94

I've got a question. Why do we need resistors in the circuit ?

If you are refering to iamback's post. It is to limit the current. These leds have normal running voltage of about 3 V. Connecting a LED to 12v battery of a bike result in a small flash, then rest in peace .

[Chipz]

Originally Posted by iamback

Thinking of making a LED indicator bulb. There is big problem of LED when used as indicator. As the led consume so less power that the Indicator flasher speed increase automatically. Due to this the blinking speed of indicator increases.

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.

[shyamhegde]

Originally Posted by ghpk

Here's the Poly-watt LED i recently purchased.

Attachment 323161

and

Attachment 323162

can anyone tell how much 10W LED Cost, and can the OM guy of BLR send it when made a pre-payment.

10Watt LED did cost Rs 650/- .
If it is a quantity deal, Om Electronics might ship it on pre-payment. I suggest, you take help from some one locally to buy and ship.

Here are the pic of 10Watt LED I got from there. I mounted it on a processor's heatsink.Used the heatsink coumpound before fastening it with screws.




Your poly-watt LED looks like a 1 or 3 Watts without the heatsink base.

[ghpk]

shyam, 10W Looks very TEMPTING.The poly-watt i got should be 1 watt.
but its very bright, could be 2 Watt, don't have technical details as i found it like a surprise on a shop who makes/repairs re-chargeable small torch/inverters.
he's the only guy who's having L.E.D. Strip and these high power L.E.D.'s

Will be checking for 10w in a day or two, its only 7km away but its in dense traffic area.

what power supply you are using for 10w one, is 7805 based p.supply.
I'll be using a 7805 and a resistor to light up the poly-watt one.

Also there's a Indian L.E.D. manufacturer but they are not responding to mails currently, i had purchased lots of pirhana L.E.D.'s from them earlier.

[shyamhegde]

Originally Posted by ghpk

shyam, 10W Looks very TEMPTING.The poly-watt i got should be 1 watt.
but its very bright, could be 2 Watt, don't have technical details as i found it like a surprise on a shop who makes/repairs re-chargeable small torch/inverters.
he's the only guy who's having L.E.D. Strip and these high power L.E.D.'s

Will be checking for 10w in a day or two, its only 7km away but its in dense traffic area.

what power supply you are using for 10w one, is 7805 based p.supply.
I'll be using a 7805 and a resistor to light up the poly-watt one.

Also there's a Indian L.E.D. manufacturer but they are not responding to mails currently, i had purchased lots of pirhana L.E.D.'s from them earlier.

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.

The LED is now in my Hero honda Splendor's hedlight, with a prjector lense. Trying out some proto type and trying to check how it works out in real application. Better than stock light and independant of engine rpm as it is direct form batt. Only one beam adjusted to low-beam hight (Splendor's high beam was anyway not usable in stock)



This is my LM317 circuit



Sorry for the bad quality of snaps. Took from my mobile phone camera for only my reference as this has been just an ametuer effort.

[anku94]

Originally Posted by Chipz

If you are refering to iamback's post. It is to limit the current. These leds have normal running voltage of about 3 V. Connecting a LED to 12v battery of a bike result in a small flash, then rest in peace .

How does a resistor reduce voltage ? Isn't it supposed to reduce current ? Oh wait, don't answer, I'll figure this out myself. Seems like I need to revise Class X electronics...although I do remember me trying out a LED on 230V Mains when I was 6 or 7....

[Chipz]

Originally Posted by anku94

How does a resistor reduce voltage ? Isn't it supposed to reduce current ? Oh wait, don't answer, I'll figure this out myself. Seems like I need to revise Class X electronics...

Hope this link help.
How to Reduce Voltage With Resistors | eHow.com

Originally Posted by anku94

although I do remember me trying out a LED on 230V Mains when I was 6 or 7....

Ya most of us would have done it. In my case it was a 3V bulb, a solenoid I made over a blade, speakers, secondary winding of a transformer, and other goods. God did have mercy on me.