I’m interested in buying bright off-road led type lights (google will show you many sources). I was wondering if there would be an easy safe inexpensive way to add a dimmer switch to them to control the brightness.
I’m pretty sure at least some LEDs are dimmable. I’m not opposed to spending a couple of bucks on a household dimmer switch to try it, but I was wondering if there was something ready made on the market.
I’d like it to: work, be safe, be cheap, be easy to install.
Any ideas?
with LEDs, the diodes themselves don’t care how bright or dim you run them so long as you don’t exceed their rated forward voltage/current. “Dimmable” LED bulbs in the case of stuff you use at home has more to do with the internal power supply and how it tolerates being run off of a dimmer circuit.
automotive LED lighting typically is driven by a PWM (pulse-width modulation) supply which varies the brightness of the lighting by changing the duty cycle. This is why car tail lights seem to “flicker” if you move your vision across them quickly.
look into something like this: https://www.superbrightleds.com/cat/dimmers/filter/Volts_Typical,12,100,3898:
A household dimmer won’t work with the DC power on a truck. It only works with AC.
LEDs need something to limit current; if you hooked up an LED to a constant-voltage power supply directly (like a car battery), it will blow up. So all LED lights contain circuits to limit current. If the LED light is a really cheap and inefficient design, it may use a resistor to limit current, in which case reducing the power supply voltage will dim it. But most high-power lights use something more sophisticated; in this case, if you reduce the voltage gradually, it will stay the same brightness until it stops working completely.
Most are multiple voltage so you can run from 12v or 24 v. They must use a complicated system to deliver fixed current, through the led, from varying voltage at the packages power supply. A simple resistor circuit would not produce a suitably constant brightness from varying voltage.