what resistor to use for LED signals?

[♣ McKraut ♣]

i went to install LED turn signals for the front and rear yesterday (brake light is still stock), and after installation i found that either side would flash only once, and then nothing at all.  also the other side would have a "bleed-over" flash as well (not sure what the tech. term for that is).  so after putting the stock blinkers back on in the front (LED still in the rear) they're now blinking, just at a very high rate (which is what i thought would happen with LEDs all around)

my question is what is the resistor i need to pick up?  i'm thinking that radioshack or autozone might carry it...couldn't find which one i need to look for though.

also, if anyone has pics of how their resistors are wired up, that would be mucho appreciated; this will be the first time to use inline resistors for me.

[BK_856er]

No first hand experience, but the load resistors that came with my Rizoma LED signals are ceramic type 3/8" square and 2" long.  They're shrink wrapped, so I can't see any markings, but my multimeter shows them as 10 ohms.  The pictoral instructions show to use two in series if required.

BK

[mitt]

No first hand experience, but the load resistors that came with my Rizoma LED signals are ceramic type 3/8" square and 2" long.  They're shrink wrapped, so I can't see any markings, but my multimeter shows them as 10 ohms.  The pictoral instructions show to use two in series if required.

BK

In series or parallel?

I have no first hand knowledge using leds in motorcycles, but I thought it would be in parallel and a resistor similar in wattage to the bulb, something like:

http://sites.google.com/site/mittelstadtc/Home/file1/ledversusincandescent.pdf?attredirects=0


mitt

[♣ McKraut ♣]

In series or parallel?

I have no first hand knowledge using leds in motorcycles, but I thought it would be in parallel and a resistor similar in wattage to the bulb, something like:

http://sites.google.com/site/mittelstadtc/Home/file1/ledversusincandescent.pdf?attredirects=0


mitt

i'm guessing parallel??  i've never done it before, so i'm not sure honestly.

[BK_856er]

In series or parallel?

I have no first hand knowledge using leds in motorcycles, but I thought it would be in parallel and a resistor similar in wattage to the bulb, something like:

http://sites.google.com/site/mittelstadtc/Home/file1/ledversusincandescent.pdf?attredirects=0

mitt

I think you are absolutely correct and I misused the term in an electrical hookup sense.  What I meant to imply was that the Rizoma package includes multiple resistors and the instructions show to use as many as needed to achieve correct blinking.  I did not need to use any resistors, presumably because I still have bulbs at one end.  Your linked diagram is a winner.

BK

[The Architect]

I have a new never used spare set of resistors lying around.  I used the same set on my m900 for led blinkers.  If you're interested let me know.   

[mitt]

  Your linked diagram is a winner.

I made the diagram last time this LED question came up. I work with power resistors often, so I am familiar sizing them, but have not done it for motorcycle. 

The problem with the really cheap little resistors, is that they won't draw enough power to look like an incandescent bulb.  And, if you size them to draw enough power, they will burn up, because they are only rated 1/4 or 1/2 watt.  You need a resistor similar in power rating as a standard bulb, probably about 10 to 25watt.  This puts you into a higher class of resistors, power resistors, that are more expensive, but not too bad ($5 each).

mitt

[BK_856er]

I made the diagram last time this LED question came up. I work with power resistors often, so I am familiar sizing them, but have not done it for motorcycle. 

The problem with the really cheap little resistors, is that they won't draw enough power to look like an incandescent bulb.  And, if you size them to draw enough power, they will burn up, because they are only rated 1/4 or 1/2 watt.  You need a resistor similar in power rating as a standard bulb, probably about 10 to 25watt.  This puts you into a higher class of resistors, power resistors, that are more expensive, but not too bad ($5 each).

mitt

The shrinkwrapped ceramic ones provided by Rizoma measure 10ohm and on the instruction picture show 10W.  They are about 2" long and 3/8" sqaure.

I've seen others, like the one in your diagram, that appear to be metal or at least metal encased, and possibly smaller.  Are these better or more robust than the ceramic type?

BK

[bullet boy]

I have 10W/10ohm on mine. In parallel, one for the left, one for the right. $1.95 a pair at Radio Shack.

[mitt]

The shrinkwrapped ceramic ones provided by Rizoma measure 10ohm and on the instruction picture show 10W.  They are about 2" long and 3/8" sqaure.

I've seen others, like the one in your diagram, that appear to be metal or at least metal encased, and possibly smaller.  Are these better or more robust than the ceramic type?

BK

For what this application requires, the cheaper the better - so ceramic would win.  The aluminum case ones are better, but probably overkill.  I didn't know if a 10W resistor would be sufficient for this application or not.  I figured it would, because the rating on the resistor is continuous, and the turn signal application is cyclical, so you could probably apply 2 times the rated wattage on and off.

mitt

[♣ McKraut ♣]

I have 10W/10ohm on mine. In parallel, one for the left, one for the right. $1.95 a pair at Radio Shack.

i'll check out the radioshack tomorrow after work....thanks for all the info.  also, don't suppose you have any pics of what your setup looks like?  i'm guessing this will be pretty straightforward, but i've thought that about many things with the bike only to prove myself wrong... 

[♣ McKraut ♣]

okay..maybe this is overkill, but i thought i would just verify that i'm on the right track here before i go trying to hook things up on my bike and potentially do something incorrectly.  are the parts below what i'm looking for, and second, is it as simple as just taking one end of one resistor, and that goes to the wire from the bike, and the other end goes to the blinker?


back of resistor package:

[mitt]

okay..maybe this is overkill, but i thought i would just verify that i'm on the right track here before i go trying to hook things up on my bike and potentially do something incorrectly.  are the parts below what i'm looking for, and second, is it as simple as just taking one end of one resistor, and that goes to the wire from the bike, and the other end goes to the blinker?


back of resistor package:

Those look like they will work.

Did you look at the diagram I linked above?  You described installing it in series which is wrong.

You need it in parallel with the new led bulb.  So, there are 2 wires going from the bike to the signal.  You want to hook 1 end of the resistor to 1 wire, and the other end of the resistor to the other wire.




mitt

[♣ McKraut ♣]

thanks mitt.  took another look at the diagram with a friend that had some idea of what he was doing, and wired these up correctly last night in parallel.  got everything connected and used the 10 ohm 10 watt resistors, LEDs front and back, and they're blinking at the right rate.  just wish one of the LEDs didn't have 4/8 led bulbs out....

[mitt]

thanks mitt.  took another look at the diagram with a friend that had some idea of what he was doing, and wired these up correctly last night in parallel.  got everything connected and used the 10 ohm 10 watt resistors, LEDs front and back, and they're blinking at the right rate.  just wish one of the LEDs didn't have 4/8 led bulbs out....

Can you swap the cluster with another and see if the same bulbs go out?  Seems odd that one cluster would have half not working.  LEDS are pretty reliable.

mitt