Reduce brightness of BigW 200 LED strings

[aarondwyer]

Hi all

I have a set of Big W 200 LED strings (2012 batch) and I have made them into a standalone decoration for halloween. But they are too bright, and I want to reduce the brightness.

These will be run with the same supply and controller that comes with the BigW lights, not an external supply / controller.

http://auschristmaslighting.com/wiki/LED_Series_Resistors

I just wanted to check that I have to follow these guidelines on the wiki and introduce 2 resistors at the start of the string, one for each 100 bulb section.

That would drop the brightness wouldn't it?

I'm still not sure what resistor value to use. But if that's going to work, then I can chop the wires from the inline controller box and take some measurements to work out what resistor to use.

Thanks
Aaron

 

[lithgowlights]

If you are connecting it to a controller then why not run it at a lower brightness %, like 50% or so?

 

[aarondwyer]

Sorry just added a bit to the message. These will be run with the BigW supply and controller that comes with the unit.

 

[David_AVD]

Yes, you can add a resistors to the string to decrease the current and therefore the brightness.

There's a wiki page that shows how the strings are wired.

Try modifying one section first by adding a 2.2K 0.5W resistor in series. You can insert it anywhere in a given section (between any two LEDs) - it doesn't have to be at the start or end of the section.

Fiddle with the one resistor value first then do all the rest.

 

[aarondwyer]

Great stuff, time to go to Jaycar to get some resistors.

So for a 200 led string there are 10 sections x 2 channels, so I'll need 20 resistors.

I thought I could just put 1 in at the start of the channel line straight after it comes out of the controller box and be done with it.

That's a lot more work than I thought and the strings are already assembled onto the ornament so it's going to be a lot of work to disassemble fix and rebuild.

Is there another way of maybe hacking the controller box to reduce the brightness.?

Aaron

 

[ecbailey]

Would reducing the voltage going into the controller box work? That would only use one resistor....

 

[aarondwyer]

Do you mean like a dimmer switch on a standard light fitting?

 

[David_AVD]

No, the single resistor idea won't work. No such luck.

EDIT: Well, it might work but the value would be critical and very very fiddly to get right.

 

[aarondwyer]

Thanks for all responses. Unfortunately I can't connect these lights to my AVD 48CH controller box since I'm using it in another part of the display. Otherwise I could run it a 30% and be done with it.

Ashame there is no quick way, so I'll have to just run it as is for this weekend.

The wife wanted mood lighting and my 4 x ball shaped chandeliers made from BigW white strings are so bright it's like sitting under a large fluro.

Aaron

 

[David_AVD]

Sounds like you need to buy a DC24 to use for Halloween!