LED Setup

Hello:
I'm in the process of helping my sons put LED lights on their motorcycles. They both ride Honda CBR600RR's. Unfortunately the control for their riding lights-voltage/flash rate-is done by a circuit board and not a flasher. The directional and riding light circuits are fused at 10A's. The original lights are 3-wire incandescent lights (12V for directional/12V for running light/Common or Ground). The LED's we are putting on are 2-wire (12V and Common or Ground). The riding lights are powered all the time. When you put the directional signal on, the circuit board cuts the 12V to the running light leg and applies 12V to the directional leg.

I know we should be able to use a normally closed (NC) relay to make this work. I could have the riding light leg connected to the NC switch side and use the directional light leg to power the relay. This way we should be able to make the 3-wire setup work with the 2-wire LED's. We know from experimenting that we have to add some resistance across the LED's to slow their flash rate down, since their current draw is less than the incandescent lights. We found that an 8 ohm/20W resistor seemed to be adequate when just hooking the lights up temporarily with jumpers.

I wanted to use a relay that was small but allowed for soldering wires to it. The space in these bikes is minimal at best. I guess an automotive type would be durable enough and perhaps one that could be component-type (PCB-?). I've done enough odds 'n ends to understand the basics. I am at loss though to know; what type of relay to get, where to get it and how to go about wiring it up. I assume I could wire up the resistor between the relay and the LED (again across the LED's ground and 12V leads). I would have to have 2 of these set up. One would be for the right side and the other for the left.

We appreciate your assistance in this father/son(s) project.
thank you

A couple of thoughts -

A. Location (country/state) might be helpful. I think I can guess but helps to know. I'll assume you are in US.

B. You can purchase relays for automotive duty at Autozone or most other auto parts places. Radio Shack sells relays. I would like to think that the automotive types are more suited to high levels of vibration.

You've certainly put good effort into explaining your situation - not everyone who posts here does so.

I'm in a bit of a rush and just don't quite get why you need the relay. I would think that simply replacing the incandescant bulb with a proper LED combination would be sufficient. What might be the issue is that you are making the LED assembly yourself and voltage/current to the LEDs is your concern. Another concern might be that the flasher circuit isn't working because the load presented by the LEDs is different.

Not sure if this is much help but best I can do. I'll check back later.

Hi:

The relay is needed as there could be an instant when the 2 separate 12V legs could be powered at the same time. So I wanted to use the directional leg to operate the relay and open the running light leg. The LED's are the ones my son's chose- so I'm accomodating both the LED's and my sons. AP&C at www.ap-c.com has a suitable relay, I think. It's model number is PAM-4. I don't need the NO side though. It's at least one for youir viewing.

Sorry about location,etc.-I'm new to forum participation. It's Don from ouside of Albany,NY

Thanks

Flush

Welcome to the board, I'm a new comer to this board as well.
Your right on track with your approach. You may not need a relay depending the operations you want. But the Sealed automotive relay is the easest package work with cheep to work with...
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Concider that it maybe easier to just buy three wire LEDs in bulb socket than to addapt the 2-wire LED signals.
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Reason is to get the run (dim) lights you will need to Limit current to the turnsignal LED or are you planning on no running lights or bright running lights.


Steve the Load resistors are required to slow the turn signal flasher because it uses a bi-metal strip that heats up for the time constant.

Thanks for the advice. We ordered some encapsulated relays today for the front of the bikes and started on the rear leds. I'll post the results when we get everything together along with a drawing if I get to make one up.

Don