Series wiring LED's

[Packer]

Bike voltage = 13+v on charge from alternator

LED's require 3.4v.

Can you wire led's in series rather like christamas tree lamps, 20 x 12v lamps straight off the mains?

4 x LED's = 13.6v ?

 

[alimey4u2]

http://www.theledlight.com/samplecircuits.html

http://www.offroaders.com/tech/LED.htm

 

[Greg Masters]

See http://www.ukgser.com/forums/showthread.php?t=34109

You'll need a 560 ohm resistor for each LED.

Greg

 

[millard]

get a bucket load for peanuts on fleabay

http://cgi.ebay.co.uk/100x-3mm-5000...tcZphotoQQssPageNameZWDVWQQrdZ1QQcmdZViewItem

if you have a look you'll find them with resistors already attached in the leads

 

[jimbo]

this will calculate here Linky Linky

 

[Packer]

http://www.theledlight.com/samplecircuits.html

http://www.offroaders.com/tech/LED.htm

Great links alimey4u2, thanks.

It would appear that as long as you have 4 x 3.4v leds wired in circuit you really don't need to worry about all these resistors at all.

I'm thinking about the possibility of a large area LED light source at the front to improve visibility. A large area LED unit instead of a small area high intensity fitting like an HID might have significant benefits in terms of visibilty to other road users.

 

[alimey4u2]

I think it's not just a question of candle power that attracts the human eye. The "snappy" action of the LED grabs attention, just make sure you have ample candle power to transmit over distance through rain/fog etc ....

 

[Packer]

I think it's not just a question of candle power that attracts the human eye. The "snappy" action of the LED grabs attention, just make sure you have ample candle power to transmit over distance through rain/fog etc ....

HID's dip and main, sadly the now 2nd rate 35watt variety but still sooooo much better than standard!

 

[(RIP) Bin Ridin]

Someone showed us an angel-light LED setup for an 1150 a good while ago. Way cool.
Bin

 

[Packer]

Someone showed us an angel-light LED setup for an 1150 a good while ago. Way cool.
Bin

"Angel-light"?

 

[Roger Chatterton]

Obviously Halo shaped

 

[davedyer]

"Angel-light"?

 

[scots_jon]

It would appear that as long as you have 4 x 3.4v leds wired in circuit you really don't need to worry about all these resistors at all.

That is not the case. The LEDs are current driven devices not voltage. The 3.4V is the nominal Vf ("forward voltage") but this will vary a lot across different parts of the same type. You need to limit the current throught the string with a resistor. Just one resistor is required as the series configuration means the current will be the same in each LED. The Vf has only a weak dependancy on current so if you put a larger voltage across the LED than it's Vf the current will rise dramtically and destroy the LED.

Make sure you calculate the resistor based on the Vf of the particular LEDs you are using as it wil also vary with type and colour of the LED.

J.