Low voltage LED’s and color

Thread Starter

Ruperd

Joined Sep 18, 2023
2
Hi all,

I am a compulsive DIY’er. Took electronics in HS many years ago.

My wife has solar charging LED mushroom lights. One light failed, wired in parallel. I purchased a 5mm 20mA white light and soldered it in place. Colors are a lot different. Old light is a yellowish white light and new one is a blueish white. I don’t know the specs on original lights.

the solar panel has 1 .2 v 1600 mAH battery and output is 2.7v. I don’t know how to measure the current.

Q how do I get a closer match in light color?
 

MrChips

Joined Oct 2, 2009
29,241
Welcome to AAC!

It might have something to do with the diode forward voltages and the current balance between diodes. Try experimenting with inserting various values of resistors in series with the blueish LED.
 

BobTPH

Joined Jun 5, 2013
7,555
An LED called “warm white” would be more yellow. Don’t know how to match it without just trying different ones.
 

crutschow

Joined Mar 14, 2008
32,918
The color of LED light is mainly determined by the LED material composition (below) and is only slightly affected by its current level, so to get a different color, you need a different LED.
1695069308964.png
 

MaxHeadRoom

Joined Jul 18, 2013
27,648
Look for low Kelvin, something around 2,000- 2,500 Kelvin.
You most likely bought ~5k Kelvin!
Look at a LED kelvin chart and it will give you an idea.
 

crutschow

Joined Mar 14, 2008
32,918
If you can measure the forward voltage of LED you want to duplicate, that will tell you fairly closely its color temperature.
 

MisterBill2

Joined Jan 23, 2018
15,689
To have that more yellow glow find the "warm white" lower color temperature LEDs. Some folks believe that they are somehow healthier. Certainly they are less conducive towards greater productivity.
 

bassbindevil

Joined Jan 23, 2014
783
The warm white LEDs often have a yellower phosphor than the cold whites. Try harvesting LEDs from dollar store flashlights if you don't have enough e-waste lying around to salvage from.
 

BobTPH

Joined Jun 5, 2013
7,555
The warm white LEDs often have a yellower phosphor than the cold whites. Try harvesting LEDs from dollar store flashlights if you don't have enough e-waste lying around to salvage from.
Those are likely to be bluer since the blue-white ones are more efficient.
 

MisterBill2

Joined Jan 23, 2018
15,689
The bottom line to this discussion is that to get it right the first try you need to purchase "white" LEDs listed to have that 2000 degree color temperature. They may also be called "warm white." LEDs. Unfortunately some sources do not have any information except price and shipping weight. I suggest avoiding them.
 
Last edited:
Top