What resistor for dimming tail lights

[Whats_a_dickfer]

I installed the injora head and tail lights kit for my trx4m. https://www.injora.com/products/injora-headlights-taillights-led-lights-kit-for-1-18-trx4m-4m-16

The tail lights are way bright, more like having brake lights on. I was thinking about soldering resistors inline, would like to drop the brightness by maybe 25 to 50%. Don't know what resistors to use. Any advice? Thanks!

 

[ferp420]

wire them in series that will cut the power to each light in half

 

[Whats_a_dickfer]

wire them in series that will cut the power to each light in half

Of course! Thanks! "thumbsup"

 

[nightcrawler48]

I know just enough about LEDs to possibly be dangerous, so here goes.

You're asking about dimming the red on the light system. The red LEDs have a voltage operating range of 1.8V to 2.2V. The low voltage will will dim the lights down and the high voltage will brighten them up. When looking at the picture on the link you posted I see each of the LEDs has its own resistor already installed. To dim the red LEDs down, you need to know what the resistance of the installed resistors is. Also, to calculate the resistor required to supply the low voltage, you need to know what the supply voltage is. There is nothing I see on the link to say what the operating voltage is for this light system.

So lets use an example here. If your system voltage is 6V and you want a dim LED, you would use a 220 ohm 1/8 watt resistor to get 1.8V to the LED. To brighten the light output you could go up to 2.2V which would require a 200 ohm 1/8 watt resistor.

If you were to wire the LEDs in series as ferp suggests, and if you left the existing resistors in place, the LEDs would probably not light up at all. The voltage to the LEDs would be to low. To supply 1.8V to both LEDs in series, you would need one (1) 120 ohm 1/8 watt resister in series with the two (2) LEDs.

I also see resistors wired to the white LEDs. White/clear LEDs use 3.0V to 3.4V so the resistors will be different resistance than those for the red LEDs.

Not sure if this helps you or not. Can be confusing when trying to figure out what you have and what you need to do to achieve what you want.

 

[heyok]

I use 1K ohms in series to the brake lights to make them look like tail lights.

 

[B-MOW71]

I installed the injora head and tail lights kit for my trx4m. https://www.injora.com/products/injora-headlights-taillights-led-lights-kit-for-1-18-trx4m-4m-16

The tail lights are way bright, more like having brake lights on. I was thinking about soldering resistors inline, would like to drop the brightness by maybe 25 to 50%. Don't know what resistors to use. Any advice? Thanks!

A trick that I do to all of my red LED taillights is to file the tip of the LED flat. It greatly reduces the light intensity and looks more like a taillight instead of a red headlight beaming out of the rear of the rig.

 

[ferp420]

could also use a sharpie to darken the bulb and the lense it shines through