Dumb RGB Colour Consistency

Charger

Apprentice elf
Joined
Nov 5, 2013
Messages
75
Just wondering if I should be expecting consistent colour when two strings of dumb RGB's are joined together. I have several strings of Ray Wu's dumb RGB's and have joined two together (100 on each) to light up a mini tree. They work fine except that there is a obvious inconsistency in colour. Almost like the entire second string is a different colour than the first. It's not as noticeable when showing the primary colours, but when mixing it is there to see. Do the RGB's require some time to settle into their colour or anything? Thanks.
 

Kitman

Full time elf
Joined
Oct 25, 2014
Messages
395
Location
Munno Para
It is possible that you are suffering some voltage drop in the second string which is causing the colours to not look the same.


With all RGB's be they dumb or smart they all require a certain voltage to light up the diodes within to the correct colour. Lighting up just red or just green or just blue you shouldn't notice much difference, however when you start mixing colours well then you are lighting up more per light which is using up and losing more voltage across the entire string. If you were to try and light the whole thing up white you might notice that as you get further along the light starts to get pink and eventually may even appear to be only red, thats because there isn't enough voltage to drive all 3 and since red uses the least amount of power it's the last one to stay on full brightness to the very end.


Grab a multimeter and whack it on the end and in the middle and see what voltage you have compared to what you started with, typically and this is my own observation with my own lights with 12v in at one end you will generally be down to about 10.5 after 100 nodes, however with 5v in you might be down to 4v after 50.


Individual results may vary, the results of some may not be the result that you experience.
 

i13

Dedicated elf
Joined
Jul 5, 2013
Messages
1,172
Sounds as though the different batches don't exactly match.

logandc99 had a similar problem here https://auschristmaslighting.com/forums/index.php/topic,5936.0.html
 

fasteddy

I have C.L.A.P
Global moderator
Joined
Apr 26, 2010
Messages
6,648
Location
Albion Park NSW
Were these bought at the same time or at different times because colour consistency can always be an issue with different batches as generally at the cheaper end of the market then LED batches are bought more based on price rather than specification, so differences can happen. It can also happen with new and older LEDs as LEDs do loose intensity after use and generally a LED life is rated on when an LED reaches 1/2 the rated light output of the LED and not when it actually dies
There can be a lot of difference between LED packages and consistent binned LED packages can vary. There is a reason it is cheap
 

Charger

Apprentice elf
Joined
Nov 5, 2013
Messages
75
Thanks for the replies. All lights are new this year, so I presume that they are all the same batch. As Kitman suggested I think a voltage drop was the culprit. injecting power where the two join seems to have rectified the issue. Multimeter didn'the indicate much of a drop, but it was obviously enough to cause a mild difference in lights side by side. Thanks again for your replies.
 

Kitman

Full time elf
Joined
Oct 25, 2014
Messages
395
Location
Munno Para
Sometimes you don't need much of a drop to cause a noticeable difference when they are side by side, however when on a house and viewed from 5 to 10 meters away you possibly wouldn't even notice it. But if your like me you know the issue is there so have to make sure it's right haha.


Glad we could all be of assistance with your issue.
 
Top