Forgive me if this information is available someplace.

(Min Idzelis) #1

Forgive me if this information is available someplace. I’ve googled a lot, and couldn’t get a reliable answer. When using multiple power sources, is it safe to power from both ends of the strip, if power source A is connected to one side, and power source B is connected to the other side? I know the grounds of both power supplies need to be connected. Do the power supply 5V lines need to be directly connected too? Or, is just the LED strip connecting the two lines enough. Does each power supply need its own 1000 uF capacitor?

Question 2: On the power supplys that have multiple 5V pins. If i’m using a single 10AWG as a power rail, can I just connect the 10AWG wire to one of the 5v pins, or do all the pins need to be connected/spliced to the 10 AWG wire?

Question 3: If I’m powering 4096 WS2811b leds, I plan on using 2x 5v40amp power supplies. I’m concerned about noise - any recommendations an fanless or quiet PSUs?

(PaulStoffregen) #2

Q1 - Depends on the design of power supply, specifically whether it will sink current if externally driven higher than its regulated output. Most power supplies will not do that. So it’s fairly safe to use 2 of them. If one is slightly higher than the other, it will just end up powering more of the LEDs. But if the power supply uses a certain type of design, like synchronous rectification, then it may end up trying to sink current from the other side if there is any imbalance or mismatch.

(Min Idzelis) #3

@PaulStoffregen Thanks for the reply. I think you answered the question if 2 supplies should be used together at all, right? I’m a little nervous that you said ‘fairly safe’ as this is pretty high power, and I don’t want to cause a fire or anything. How can you tell if the PSU uses synchronous rectification? Would using two of these together be safe?

(Yves BAZIN) #4

@Min_Idzelis how many leds per strip do you have ?
In my build I have 48 strips of 123 leds and I have powered them at only on side
If you have several strips or panels (if you are using those) it is recommended to power each strip/panel separately.

(Min Idzelis) #5

@Yves_BAZIN Thanks. I’m planning on 40 strips of 120 leds. It sounds like with only 120 wide, i don’t need power on both ends. Do you have any suggestions on power supplies? Would 2 smaller 40amp power supplies, each powering 20 strips be quieter than 1 big 80amp power supply?

(Yves BAZIN) #6

@Min_Idzelis again it will depend on how far the strips are from each other. You need to reduce the length of the power to a minimum to reduce the power lost due to ohm’s law. The more amps the bigger the wires from your power supply.
4800 leds in white full power is 288A. You’ll be providing like a bit more than 1/4 of the maximum power so be carful not to go over a brightness of 64 to not overdraw current from your power supply/supplies.
But already at 64 brightness it’s pretty bright :wink:
It will depend of your usage.
Then one or 2 doesn’t change. Be careful of placing them in a place where they can ‘breathe’ if you do not have cooling systems.

(Robert Atkins) #7

Connect the grounds but cut the positive rail in the middle and you’ll be fine.