LED indicators

**Akzle** · 15th November 2012, 18:03

did search=nothing=new thread.

so i see these LED indicator bizos. and i see these LED resistor bizos (for retro-fitting to standard incadescent bulb set ups)

now, the resistors specified are 50W 6 ohm and reckon to connect in parallel with the bulb. this strikes me as weird. it also says they generate a lot of heat and not to have near plastics.. but with a SFA duty cycle i wouldn't think it a problem??

i woulda thunk to connect a resistor in series with the hot lead. no?

incadescent bulb is, what? 15W, LED is .05, so doesn't draw enough to trip the flashy-majig. figuire (by math) that a 15w bulb has <10 ohm resistance. so the theory is to chuck a 10 ohm resistor in series.

what am i missing?!

**bogan** · 15th November 2012, 18:26

Buy a flasher that is designed for LED indicators. Resistors just add unnecessary complexity.

**neels** · 15th November 2012, 19:11

Originally Posted by Akzle

what am i missing?!

That you will drop too much voltage across a resistor in series to make the LED work, because the LED will already have a resistor in series to drop around 10 of the 12 volts supplied, and 10 ohm in series with just the LED would allow too much current and cook it.

Resistor in parallel is just to draw some more current to make the flasher unit work properly, or as above replace the flasher with an electronic one instead of thermal and problem solved. Don't think that works on my DRZ because the flasher is part of another box, so resistors it is.

**bogan** · 15th November 2012, 19:20

Originally Posted by neels

That you will drop too much voltage across a resistor in series to make the LED work, because the LED will already have a resistor in series to drop around 10 of the 12 volts supplied, and 10 ohm in series with just the LED would allow too much current and cook it.

You'll probably find inside the indicator there is 4 LEDs in series, and a resistor which only drops a couple of volts.

**Akzle** · 16th November 2012, 06:11

Originally Posted by bogan

You'll probably find inside the indicator there is 4 LEDs in series, and a resistor which only drops a couple of volts.

can't remember what resistors are inside. starts with a 2# either x10 or x1000 and 5% 1/4W
.for looking.

i was gonna say... LEDs run at ~9v

anyhow. we'll see about all that. 8$ for a set of resistors, or 70$ for a flasher unit. i wonder.

**Voltaire** · 16th November 2012, 08:03

I fitted led indicators to my Norton...and its postive earth to make matters more interesting.

I got the led indicators off Jonny Ballistics on TM after seaching widly even ebay but the post from the US is the deciding factor. the more leds the better and they have the all important E numbers for you testing station man.

The Electrician in me can't see the point of fitting resisitors ....its just another bodge.

I got an led flasher from AU ebay.. 12v. 0.02A to 20 amp...think it was $20 plus 12 for post....

then I see them in supercheap for $30-40

no probs getting a WOF and they look more discreet than the hidious early 70's Lucas crap.

**bogan** · 16th November 2012, 08:06

Originally Posted by Akzle

can't remember what resistors are inside. starts with a 2# either x10 or x1000 and 5% 1/4W
.for looking.

i was gonna say... LEDs run at ~9v

anyhow. we'll see about all that. 8$ for a set of resistors, or 70$ for a flasher unit. i wonder.

You must shop at a boutique LED flasher outlet store... those little fuckers are about 4 bucks on ebay

**Haggis2** · 16th November 2012, 09:38

I bought a relay at repco for $12 not that long ago that fixed my flash rate

**Akzle** · 16th November 2012, 11:37

Originally Posted by bogan

You must shop at a boutique LED flasher outlet store... those little fuckers are about 4 bucks on ebay

i don't buy shit online, except TM. and that was for http://www.trademe.co.nz/motors/moto...-533430512.htm

Originally Posted by Haggis2

I bought a relay at repco for $12 not that long ago that fixed my flash rate

sweet, i'll look into it. i haven't had a nosy at what's actually on the bike yet so we'll see.

Originally Posted by Voltaire

The Electrician in me can't see the point of fitting resisitors ....its just another bodge.

I got an led flasher from AU ebay.. 12v. 0.02A to 20 amp...think it was $20 plus 12 for post....

then I see them in supercheap for $30-40

no probs getting a WOF and they look more discreet than the hidious early 70's Lucas crap.

ayye ayye. i'll look into it. ta.

how's this for maths.
stock bulb is 5W, draws .28A, resistance of 42R (calculated) 48R (measured)
LED bulb has 3x 240R resistors visible (sealed unit), draws .02A calculated resistance of 600R

so if i wheck a couple of 5W, 47R resistors parrallel (basically the same as having a bulb connected) with teh LED bizos - i'm in business, jah?
the advo'd ones for retrofitment are 50W 6R. which confses me but i'm sure i'm still missing something.

**bogan** · 16th November 2012, 12:13

Some stock bulbs are 21W, and you have your front and rear bulbs in parallel, so 42W total, so a 50W load resistor is in the ballpark at least. This is why I tell people to use LED flashers, then there is no issue matching old bulb wattage to load resistor to LEDs.

Tell you what, I'll sell you one locally for 20bucks, it'll save you buying from overseas. Though it'll likely take me 10-28 days to get it...

**Akzle** · 16th November 2012, 18:05

this f*ing thing is doing my head in.
switch tests OK.
switch to flasher unit tests OK. (ie flasher has no continuity when off and connects when switched to L+R)
then it gets interesting.

every wire for the existing indicators has continuity to ground. wherever the switch is and whether flasher is connected or not.
WTF?!?!

**Akzle** · 16th November 2012, 18:23

Originally Posted by bogan

Tell you what, I'll sell you one locally for 20bucks, it'll save you buying from overseas. Though it'll likely take me 10-28 days to get it...

five bucks and a bag of chips.

**Akzle** · 16th November 2012, 18:43

why google better search than KB?

http://www.kiwibiker.co.nz/forums/ar...t-139376.html?

**Owl** · 17th November 2012, 08:41

You could always try an auto-sparkey?

I did that, he said "I know what will fix that", plugged in a Tridon HD12 relay and presto. $15 and been mint for the last 5 years.