WS2812 LED strip power supply humming - Page 1
Forum section: electronics / beginners

author: HerbCSO
author_rank: Newbie
timestamp: June 27, 2020, 12:42:47 pm
content: I just posted another question about this project (https://www.eevblog.com/forum/beginners/ws2812-led-strip-cable-connectors/) but since this is a different topic I thought it'd be better to separate them. Apologies if they should have been the same post.I got one of these cheapo 5V power supplies that you find in 3D printers and the like to power my WS2812 LED strips (for reference, I got these specific ones:https://www.amazon.com/gp/product/B07BKQZLDL). As I said in the other post, I have 3 strips of 1m each with 144 LEDs/m, so 432 LEDs in total. The specs say they draw 30W each at full power, and sure enough when I hooked the power supply up to a Kill-A-Watt and ramped all the LEDs up to full power, it read 89W, so far so good.The power supply I got is rated for 200W, so theoretically should have plenty of capacity for this application (specifically this one:https://www.amazon.com/gp/product/B07KCVBZ18).Here's the rub: when I ramp the LEDs up to full brightness, full white, the power supply begins to audibly hum very annoyingly. I believe it is coil whine, and I think I have it isolated to the one in the attached picture.I'm thinking about covering this bad boy completely with silastic (well, general HW store brand silicone caulk, e.g. this stuffhttps://www.lowes.com/pd/GE-Silicone-2-2-8-oz-Clear-Silicone-Caulk/1043637) - is that a hugely bad idea? Will it cause the coil to overheat and catch fire? Will it do other bad things like corrode the board? Is there something else/better I can do about this? Should I just buy a different power supply altogether? ;]Thanks in advance for any input you might have!

author: JustMeHere
author_rank: Frequent Contributor
timestamp: June 27, 2020, 02:56:40 pm
content: Many solids conduct heat better than air. Aluminum, copper are obvious. Potting material does this too; not as well, but better than air. Maybe lay down caulk on some paper. Put ice at one end, and see how quickly the other end's temperature goes down.

author: james_s
author_rank: Super Contributor
timestamp: June 27, 2020, 07:10:49 pm
content: Normal silicone caulk releases acidic vapors when it cures so it's generally a bad idea to try to pot electronics in it, although I have used it on HV stuff without issues so YMMV. Really though the proper thing to do is either buy a better quality power supply, or vacuum pot the magnetics in epoxy resin.

author: HerbCSO
author_rank: Newbie
timestamp: June 28, 2020, 06:07:18 pm
content: Quote from: james_s on June 27, 2020, 07:10:49 pmI don't think I have the option of vacuum potting, unless there's an easy trick to that which I'm not aware of.Do you have a recommendation for a better power supply for this application?

author: james_s
author_rank: Super Contributor
timestamp: June 28, 2020, 06:16:35 pm
content: You don't need a deep vacuum, even one of those handheld things for testing automotive vacuum systems will work, then you need some kind of sturdy container to set the thing you're potting inside.I don't have any specific recommendation but there are lots of very well made power supplies out there. How much power does your strip draw at max brightness?

author: HerbCSO
author_rank: Newbie
timestamp: June 29, 2020, 12:10:42 pm
content: Quote from: james_s on June 28, 2020, 06:16:35 pmThat's a bit more effort than I'm willing to make on a $20 power supply... ;] But I appreciate the infos!Quote from: james_s on June 28, 2020, 06:16:35 pmIt draws about 90W.