LED bike light mod

[alphatarget1]

I bought a bike light from REI which has 5 LEDs. It's brighter than the crappy Cateye 3 LED I had before. It would be nice if it were still brighter. I was thinking maybe putting the 1/2 size AA batteries in it to increase the voltage. Would that blow the LEDs? My other flash light takes 4 AAAs and only has 3 LEDs...

 

[bobdole369]

Almost certainly.

The circuit has a current limiting resistor inline with the LED's, (and all the led's are either in parallel or series, depending on the design.) Doubling the expected voltage will likely blow that resistor, it's possible you would see no difference whatsoever if the current limiter can handle the extra voltage.

See LED's are constant voltage devices. When forward biased they allow enough current to get through them to allow the proper voltage drop across. Everything else is soaked up by the current limiting resistor. If there is too much power going through the circuit something will blow.

 

[Rubycon]

Overdriving LEDs will shorten their life expectancy considerably and many cheaper products are already overdriven - sometimes very badly. If you need more light consider another emitter type or go to HID.

 

[JulesMaximus]

Get the Planet Bike Superflash blinky for rear lighting. If you want a good front light that is small, powerful, and lightweight I'd go with a Dinotte light.