What determines idle power draw (what Ac power do i need?)

3
Posted 2nd Jun
I want to learn abit about power/quality of devices.


I recently bought this 5M strip of led lights from china and threw the AC power away because it was extremly light and cheap feeling
was sucking 3 watts in idle ,and got hot, was a fire waiting to happen.

aliexpress.com/ite…8cK

I bought a more expensive Ac power from a reputable place
(one it came with was 12V 3A, so just assumed from that)

and bought this

cpc.farnell.com/pro…269

I then compared the one I ordered with another one I have laying around my house that came with some other LED's, this is a laptop type AC power and does not draw as much so never binned it.

Did some comparisment and this was my findings

Cheap China laptop type 0.5w Idle
CPC smaller one 0.7w

Picture of them here with the details

ibb.co/K73…tW2


Questions I have

My led strips max out at 12W, is the PSU I bought for these the correct one?
(don't care on the type, whatever uses the least idle power)

I was suprised the one that I would of imagined would be better quality uses more power, is this soley because of the more airflow or is it quality?
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3 Comments
i dont think its about the power draw - all PSUs will draw some idle current; the larger-drawer may be better, because of capacitors, buffering, components etc.

ultimately the only thing that matters with any PSU is : what will happen when the current drawn is too high. i had a 4-way powerblock with USB connectors, and plugging in too much power-drawer into the USB caused it to overheat. And the overheating had the effect of shutting off power for a few seconds, then put it back on; so the devices were seeing power/no-power/power/no-power, and the device was getting too hot. ultimately it would have burned itself out, maybe shorting on the way, and maybe causing a fire.

almost everything is made in china. (Harp back to the 60s+70s when every piece of cheap garbage came from Japan).

Ultimately the quality from China is improving and will (hopefully) continue to improve.
CrispEditor02/06/2020 16:52

i dont think its about the power draw - all PSUs will draw some idle …i dont think its about the power draw - all PSUs will draw some idle current; the larger-drawer may be better, because of capacitors, buffering, components etc.ultimately the only thing that matters with any PSU is : what will happen when the current drawn is too high. i had a 4-way powerblock with USB connectors, and plugging in too much power-drawer into the USB caused it to overheat. And the overheating had the effect of shutting off power for a few seconds, then put it back on; so the devices were seeing power/no-power/power/no-power, and the device was getting too hot. ultimately it would have burned itself out, maybe shorting on the way, and maybe causing a fire.almost everything is made in china. (Harp back to the 60s+70s when every piece of cheap garbage came from Japan).Ultimately the quality from China is improving and will (hopefully) continue to improve.


I am just assuming the one that did better is cheaply made because its the same company that made the garbage I binned but in the laptop form, so I assume it was worse quality, but it does better in the idle power drawer, I assume this is because it has more airflows ect, but as i'm no expert I'm not sure if I am assuming incorrectly.

Did the laptop type win because of the bigger form factor or is it just better quality?
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