Struggling to fix voltage drop in my LED circuit

Thread Starter

nsandler

Joined May 7, 2024
3
My goal is to power 600 WS2812B RGB LEDs at full power. Currently, when all LEDs are set to white (255, 255, 255) at max brightness, a color gradient from white to red is displayed. I discovered that this also happens when, for all LEDs at max brightness, any one RGB channel is maxed out and another is ~50%. For example, the issue would also occur if all LEDs were set to R=255, B=127, G=0 at max brightness.

I've experimented with higher amperage power supplies and different wire gauges (12, 16, 20) but I can't seem to figure this out. I would appreciate any and all comments, concerns, or guidance! See below for details of my circuit and please let me know if additional information is needed.

Circuit specs:
- I'm using 2 of these 5V LED strips daisy-chained together. The total length of the LED chain is 32.8 ft (16.4 ft per strip).
- I'm using 2 of these 5V, 40A, 200W power supplies: one at the start of the LED chain and one where the two strips are chained together. There's no room for a third power supply!
- The distance between each power supply and the LED strip is 8 ft. This 20 gauge, tinned copper wire is used to bridge both distances.

Other information:
- I use this microcontroller (ESP32) to drive the LEDs. This receives power directly from the first power supply.
- These connectors are soldered onto the ends of the power cables, LED strips, and power supply terminals.
- I settled on 40A power supplies because I found that a single WS2812B LED consumes about 0.06A at max brightness (source: reply #7). So for 600 LEDs, I need 0.06A X 600 = 36A. I couldn't find 36 amp power supplies so I went with 40 amps.
 

BobTPH

Joined Jun 5, 2013
9,301
You need to supply power at both ends and possibly at points in between. Use heavy wire to bring power to the other points, probably 14 AWG. The problem is caused resistance of the small traces carrying power along the strip.
 

Ian0

Joined Aug 7, 2020
10,277
The general recommendation for LED strip is a maximum of 5m in a single length for 12V and 10m for 24V.
If you have more than that, you will have too much volt drop down the common return.
 

jeffkrol

Joined Dec 8, 2015
56
My goal is to power 600 WS2812B RGB LEDs at full power. Currently, when all LEDs are set to white (255, 255, 255) at max brightness, a color gradient from white to red is displayed. I discovered that this also happens when, for all LEDs at max brightness, any one RGB channel is maxed out and another is ~50%. For example, the issue would also occur if all LEDs were set to R=255, B=127, G=0 at max brightness.

I've experimented with higher amperage power supplies and different wire gauges (12, 16, 20) but I can't seem to figure this out. I would appreciate any and all comments, concerns, or guidance! See below for details of my circuit and please let me know if additional information is needed.

Circuit specs:
- I'm using 2 of these 5V LED strips daisy-chained together. The total length of the LED chain is 32.8 ft (16.4 ft per strip).
- I'm using 2 of these 5V, 40A, 200W power supplies: one at the start of the LED chain and one where the two strips are chained together. There's no room for a third power supply!
- The distance between each power supply and the LED strip is 8 ft. This 20 gauge, tinned copper wire is used to bridge both distances.

Other information:
- I use this microcontroller (ESP32) to drive the LEDs. This receives power directly from the first power supply.
- These connectors are soldered onto the ends of the power cables, LED strips, and power supply terminals.
- I settled on 40A power supplies because I found that a single WS2812B LED consumes about 0.06A at max brightness (source: reply #7). So for 600 LEDs, I need 0.06A X 600 = 36A. I couldn't find 36 amp power supplies so I went with 40 amps.
First a disclaimer.. all I do is "play" at designing and building aquarium led lighting so I'm no electronics "guru".
That said my "recommendation" is ditch the 2 power supplies for one.
Wire so as to feed both ends and the middle.
Works great on long runs of 12 or 24v strips..

Higher amps isn't going to help if your voltage drops.

Oh and probably get a name brand power supply.
Strips state they are 90w.
A Meanwell ps is $28.99 for 5V 200W
10% overr est. specs .
PART #: LRS-200-5
4.5-5.5 adj voltage

I've always done at least 15%..
$34.49 for a 350W if you think the Meanwell 200w isn't sufficient.
PART #: LRS-350-5
https://www.ledsupply.com/power-supplies/mean-well-lrs-enclosed


Red leds having the lower V(f) will still light as your voltage gets insufficient to light the green/blue leds..
 
Last edited:

BobTPH

Joined Jun 5, 2013
9,301
WS2812B are 5V. If you use WS2815B, which are 12V the current is smaller, so less voltage drop. I am running nearly 5m, fed from only one end, and they are completely uniform.

I believe each chip limits the current to something like 15 mA.
 

jeffkrol

Joined Dec 8, 2015
56
WS2812B are 5V. If you use WS2815B, which are 12V the current is smaller, so less voltage drop. I am running nearly 5m, fed from only one end, and they are completely uniform.

I believe each chip limits the current to something like 15 mA.
There are 3 independent LEDs in each chip which I think they call a " pixel"
Max total current is 50- 60mA I believe.

With every single LED on at full brightness, each breakout board can pull about 60mA (20mA per color channel).
https://learn.sparkfun.com/tutorial... WS2812 and WS2812B requires,about 3.3V to 5V.
 

BobTPH

Joined Jun 5, 2013
9,301
You don’t have to instruct me about WS2812B. I have used them in dozens of circuits.

I was trying to inform YOU about WS2815B, which is the same thing except powered with 12V with 3 LEDs in series for each color per chip drawing less than a third of the current for the same length. These allow longer runs before losing enough voltage to dim the pixels or alter the color.
 

jeffkrol

Joined Dec 8, 2015
56
You don’t have to instruct me about WS2812B. I have used them in dozens of circuits.

I was trying to inform YOU about WS2815B, which is the same thing except powered with 12V with 3 LEDs in series for each color per chip drawing less than a third of the current for the same length. These allow longer runs before losing enough voltage to dim the pixels or alter the color.
Gee thanks but it doesn't matter to ME in the least but info is always appreciated.
Second since the o/p already has the 5v ones doesn't actually help them either..
 

BobTPH

Joined Jun 5, 2013
9,301
Second since the o/p already has the 5v ones doesn't actually help them either..
Oh, right, because no one has ever fixed a problem by changing their choice of parts.

I already gave solution for the original part as well.

Sorry I confused you with the TS. My posts about WS2812B were meant for the TS.
 

jeffkrol

Joined Dec 8, 2015
56
Oh, right, because no one has ever fixed a problem by changing their choice of parts.

I already gave solution for the original part as well.

Sorry I confused you with the TS. My posts about WS2812B were meant for the TS.
Yea and I suggested buying one big power supply instead of 2 smaller power supplies..
So I guess I kind of stuck my foot in my own mouth...
Apologies..

I do think the 2 supplies is the issue .
 

BobTPH

Joined Jun 5, 2013
9,301
I do think the 2 supplies is the issue .
How? The gradient form white to red indicates he is probably losing more than 2V along the 10m of strip, which is no surprise when trying to out 36A into it.

There is plenty of resistance to allow another supply after 10m.
 

jeffkrol

Joined Dec 8, 2015
56
How? The gradient form white to red indicates he is probably losing more than 2V along the 10m of strip, which is no surprise when trying to out 36A into it.

There is plenty of resistance to allow another supply after 10m.
Well first look at what He did..
I'm using 2 of these 5V, 40A, 200W power supplies: one at the start of the LED chain and one where the two strips are chained together.
The distance between each power supply and the LED strip is 8 ft. This 20 gauge, tinned copper wire is used to bridge both distances.
BUT
I've experimented with higher amperage power supplies and different wire gauges (12, 16, 20)
I can't see it not working in the above..
So I, in my ignorance, think how power supplies do not always work together unless designed to work together.
So try one big supply.
They actually have one that should work.. 5V 200W (
Aclorol 5V 40A 200W Power Supply)

BUT I don't trust it.
Well not over the Meanwells I posted.
They could try and wire the ONE as you and I say..
beginning,middle, and end at around 8ft from ps to strips.

The strips are powered every 5m its not 10m.
one at the start of the LED chain and one where the two strips are chained together.
hmm just noticed it has a manual switch for 110.220v..
Maybe on the wrong input?
 
Last edited:

Thread Starter

nsandler

Joined May 7, 2024
3
Well first look at what He did..

I can't see it not working in the above..
So I, in my ignorance, think how power supplies do not always work together unless designed to work together.
So try one big supply.
They actually have one that should work.. 5V 200W (
Aclorol 5V 40A 200W Power Supply)

BUT I don't trust it.
Well not over the Meanwells I posted.
They could try and wire the ONE as you and I say..
beginning,middle, and end at around 8ft from ps to strips.

The strips are powered every 5m its not 10m.


hmm just noticed it has a manual switch for 110.220v..
Maybe on the wrong input?
Thanks for the link! I'll give the 5V 200W PSU a try
 
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