Tips on how to convert to LED light?

Rat Rod Bikes Bicycle Forum

Help Support Rat Rod Bikes Bicycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Probably a bad switch. Sounds like it's still passing current through. A relay uses a low power circuit to switch a high power circuit. Say you want to run some powerful lights, like in a car. If you use a simple circuit battery>switch>lights, the entire current draw of the lights will go through the switch, including a spike at the switch contacts when the circuits are opened or closed. The more current draw, the higher resistance for a given voltage, which is heat. A higher voltage allows the same current to run more efficiently, reducing resistance. It's all in the equation for W=A x V. If you have a 50W light running on a 6V battery, the current draw will be about 8.3A. That same light running on a 12V battery would only draw about 4.2A. For the higher voltage circuit, you can probably also run smaller wires as the lower current draw doesn't require as large a gauge wire. With the modern regulations for mileage and emissions basically requiring lower weights to meet along with increased electrical demands are big reasons car companies are looking to move to 48V circuits (and went from 6 to 12 decades ago). Oh, relays! So, a relay is fancy switch that uses a small power circuit to switch a large power circuit. The small power circuit is used for the switch, so when you close that circuit it creates an electromagnetic field within a coil inside the relay. That field pulls on the switch for the high power circuit, closing it to allow the larger current that the relay is designed to handle to flow through to the lights. Buying a switch that can handle the same current as the high power circuit of the relay is a lot more expensive and less reliable.
 
Whoops, I just looked at the pic actually using my eyes! You should really only be switching either power or ground. Say you switch the positive, you would run that from the battery to the switch then from the other terminal on the switch to the LEDs. The ground would go from the LEDs to the battery.
 
Whoops, I just looked at the pic actually using my eyes! You should really only be switching either power or ground. Say you switch the positive, you would run that from the battery to the switch then from the other terminal on the switch to the LEDs. The ground would go from the LEDs to the battery.

Only seem to get the switch to work by contacting the pos./ neg. battery terminals, when I try switching the contacts on the pos. or neg wire, nothing.

The switch that is already wired into the board is still in play...it switches between low and high (either 1 or 2 lights)

Does this switch need to go?
Seems like I should be able to interrupt the circuit somewhere with the switch I bought and get the thing to work...
 
image.jpg
image.jpg
 
Getting closer!
Syclesavage talked me through this thing, and now I just need to solder or splice these wires together...pic below illustrates how I'm hoping to pull this off.
If I need to, I can solder the switch wires directly to the board and battery pack, but maybe I can join these wires outside the box...?

Anyway, the whole thing pops in perfectly.

image.jpg
image.jpg
image.jpg
 
Nice!
Now that I just picked up a new soldering iron, I guess I'll be getting more into lighting!

Got the switch soldered onto the right spot, I hope, and it works like a charm!
Here's the rest of the pics...Thanks all!

image.jpg
image.jpg
image.jpg
image.jpg
image.jpg
 
I've had good luck using the LED flashlights from Harbor freight for parts. They come apart pretty easy and with a minimum of hackery you get a bulb and a 3 battery power pack.
 
Aw, man, I hope you get this perfect, cuz that light is the schnizzle, big time.

With bright leds getting cheaper and cheaper, there are a ton of options.

If you consider using anything that uses the CR123 batteries you find in more expensive small flashlights, look at the Surefire web site and buy the batteries there. The Surefire 123s are priced reasonably for that type of battery.

There are a number of small USB rechargeable bike lights now that might fit right into a larger headlight.
 

Latest posts

Back
Top