Hey KITAs, I 'm making a project that has 4 1 amp leds driven by one 18650 battery

[G+_James Hughes]

Hey KITAs, I'm making a project that has 4 1 amp leds driven by one 18650 battery. It works great but the lights are brighter than I would like. I know that pwm is what I need to use to adjust the light brightness, jus can't find anything small enough to fit in the project. I've looked on amazon, adafruit, sparkfun, and ebay. I guess I need to try bangood and aliexpress. If you know of something I would appreciate a link. Cheers! James

[G+_Jason Perry]

Why pwm is it remote controled? I would just use a variable resistor

[G+_Michael Hagberg]

Would you have room for 4 pcs of a TO-220 MOSFET or SCR. With heatsink and airflow.

[G+_James Hughes]

When I searched on banggood it brought up some pwm dc motor controllers. Would they work?

[G+_David Alitz]

A little attiny45 can do pwm and is pretty small. You can program them with an Arduino. It's been a while since I played with them; but there's plenty online.

[G+_Jim Hofmann]

555 timer?

[G+_Jim Hofmann]

Just had this come thru on Instructables for attiny45. Same size as a 555 with more (and easier) options. Could drive 4 MOSFets from 1 pwm and a AI for pot input. Might have to try one myself.

 

http://www.instructables.com/id/Attiny-Programmer-using-Arduino-UNO

[G+_John Sullivan]

An 18650 battery puts out about 3.7 volts. You didn't tell us how you have your LEDs wired, but assuming they are in parallel, you're sending 3.7 volts to a bulb that is probably rated for 1.7 volts, so yes, it will be very bright (for a little while)

 

Some LEDs are actually a package, and includes and inline resistor, so that the LEDs can accept higher voltage, but you didn't mention what yours are rated at. If they are just LEDs by themselves, with no inline resistor, that is probably your problem.

 

If you want to give us more exact information, perhaps we can help you better.

[G+_James Hughes]

cosmic Ray here's the info I got from the website where I bought the leds.

Forward Current: 300-350mA

Forward Voltage: 3.2-3.4V

Viewing Angle: 140 deg

Luminous Flux: 100-110LM

Output Power: 1W

[G+_David Alitz]

With your supply voltage you can determine what resistor you need to prolong the life of your LEDs (over voltage will eventually burn them out) with Ohm's law. If you just want them generally dimmer, you could aim for the low end of the voltage required.

ohmslawcalculator.com - LED Resistor Calculator

[G+_James Hughes]

David Alitz thanks for the link.

[G+_John Sullivan]

James Hughes One Watt!! No wonder they seem bright! Are you sure those are not Maximum values?

 

If you don't mind, could you post the link to the website where you found those values. They are quite a bit higher than I was expecting and I'd like to take a look at that spec sheet.

 

Thanks.