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Author Topic: power a controller board via USB 12V/5A  (Read 3046 times)

chenks

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power a controller board via USB 12V/5A
« on: April 04, 2019, 07:17:30 PM »

so i've ordered a little controller board to run some LED strips (it works with Philips Hue but for a fraction of the price).
it requires to be powered 12V/3A(or 5A for longer strips).
i don't fancy having it plugged into the mains, but then though maybe i can power it via USB using the yellow USB charging port on my NUC server that is sitting next ot where it'll be located (yellow denotes a powered USB port for charging)

the controller board has a barrel type connector, so had a google and came across this - https://www.amazon.co.uk/gp/product/B01G56J4I6

should this work?
has anyone done anything similar?

[Moderator edited to simplify the link.]
« Last Edit: April 05, 2019, 12:08:52 AM by burakkucat »
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chenks

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Re: power a controller board via USB 12V/5A
« Reply #1 on: April 04, 2019, 07:19:41 PM »

on digging a bit deeper it only gives out 0.45A, so that's knocked that one out.
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Ronski

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Re: power a controller board via USB 12V/5A
« Reply #2 on: April 04, 2019, 07:31:03 PM »

I was just going to say that a USB port will not supply 5 amps, but you've discovered that.

It should be very easy to purchase a suitable supply, which will of course have to plugged into the mains - as is your NUC.

I have recently purchased some 24v 10 meter long RGB strips for a garden project, but I haven't progressed much further yet.
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chenks

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Re: power a controller board via USB 12V/5A
« Reply #3 on: April 04, 2019, 07:44:53 PM »

for the short length of strip 3A should be sufficient, 5A is only recommended for over 5 meters.
i have found some that will do 2A - https://www.amazon.co.uk/kenable-Power-Cable-2-1mm-2000mA/dp/B00SCBAE00

indeed a suitable mains supply is easy, but was hoping to keep it off mains if possible.

[Moderator edited to simplify the link.]
« Last Edit: April 05, 2019, 12:10:35 AM by burakkucat »
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Ronski

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Re: power a controller board via USB 12V/5A
« Reply #4 on: April 04, 2019, 08:35:08 PM »

But what is off mains? My cryptic point was that even your NUC is mains powered. You could of course use a 12v battery and recharge it via solar power.
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chenks

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Re: power a controller board via USB 12V/5A
« Reply #5 on: April 04, 2019, 09:14:07 PM »

"off mains" as in not directly plugged into a mains socket.
this is for indoor use so a big 12x battery with solar power isn't exactly useful, workable or desirable in the location.

the main reason for wanting to see if this power method was possible is that i've already for 11 items plugged into the mains in this corner of the room (via 2 x 6 socket multi-bars each powered from 2 mains sockets on the wall). i'm really not wanting to drive anything else from the mains sockets if at all possible.
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Ronski

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Re: power a controller board via USB 12V/5A
« Reply #6 on: April 04, 2019, 10:01:36 PM »

That makes sense,  how many of the items are 12v? Perhaps an efficient larger power supply could be used to power multiple pieces of equipment, you could even distribute the power via a suitable fuse board.
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chenks

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Re: power a controller board via USB 12V/5A
« Reply #7 on: April 05, 2019, 07:45:36 AM »

it's the corner of the living room so it's...

TV
NUC
2 x external HDDs
Bluray player
Cable STB
Cable modem
Router
WIFI AP
Network Switch
Hue Bridge
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Ronski

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Re: power a controller board via USB 12V/5A
« Reply #8 on: April 05, 2019, 06:41:36 PM »

Quite a lot of that is likely to be 12v, could you not buy a large 12v supply and build a fused distribution unit and do away with a lot of transformers?
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chenks

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Re: power a controller board via USB 12V/5A
« Reply #9 on: April 06, 2019, 09:53:05 AM »

i'm not electrician and that type of project may be outwith my comfort zone.
also, i doubt something like that would look "pretty" in a living room
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chenks

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Re: power a controller board via USB 12V/5A
« Reply #10 on: April 06, 2019, 05:43:15 PM »

not sure if this would actually do the job ?
https://www.amazon.co.uk/gp/product/B071WW4Q7W

although it may have the same output ampagge limitiation
« Last Edit: April 06, 2019, 05:47:54 PM by chenks »
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Ronski

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Re: power a controller board via USB 12V/5A
« Reply #11 on: April 07, 2019, 10:20:28 AM »

That will be a no, you've stated you need 3 amps, the product specification states 2 amp maximum

Quote
[Perfect Design]: Built-in identification resistor,Input: 5v USB A male;Output: 12v(Ī1);Max current: 2A; Connectors: DC jack 5.5*2.1mm to USB A male.

You've stated that the NUC can supply 0.45 amps on it's USB port, so not accounting for loses when converting to 12v the absolute maximum at 12v would be 1.08 amp, it will be less though as the conversion will not be 100% efficient.

I would not be trying to power RGB LED's from a NUC
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ejs

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Re: power a controller board via USB 12V/5A
« Reply #12 on: April 07, 2019, 12:42:10 PM »

2A maximum input current from the 5V USB.

0.45A * 5V = 2.25W

2.25W / 12V = 0.1875A max current at 12V.
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sevenlayermuddle

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Re: power a controller board via USB 12V/5A
« Reply #13 on: April 07, 2019, 01:37:04 PM »

Agree with ejsís calculations. :)

Iíve never been a fan of USB power.   My reasoning  is that for a given appliance wattage, the lower the voltage, the higher the current.    Imho (ejs, correct me?) This has a number of possibly undesirable consequences...

1. As in this case, the USB source may be unable to supply sufficient current.

2. Under fault conditions of a poor (resistive) connection, the heat generated is proportional to current, so a low voltage (USB) solution can sometimes be more of a hazard than a higher voltage, lower current, solution.

3. Higher current applications can lead to a significant voltage drop over the length of a thin USB cable, so you no longer see the full 5V at the far end.  This can cause things to just not work.

In practice too, low voltage USB does not necessarily equate to safety.   I once managed to trap a fine Apple keyboard USB cable under the stand of a monitor, where  it became progressively more chaffed over time.   I only noticed it had become chaffed after seeing a few actual sparks and smoke, when it eventually shorted.
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chenks

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Re: power a controller board via USB 12V/5A
« Reply #14 on: April 07, 2019, 02:09:41 PM »

That will be a no, you've stated you need 3 amps, the product specification states 2 amp maximum

You've stated that the NUC can supply 0.45 amps on it's USB port, so not accounting for loses when converting to 12v the absolute maximum at 12v would be 1.08 amp, it will be less though as the conversion will not be 100% efficient.

I would not be trying to power RGB LED's from a NUC

did i?
the post where i mentioned 0.45A was about the cable i linked to, not the USB port on the NUC

I actually did see a cable that said it gave 2A out at the end, but it was an item that was no longer in stocker, and even then 2A was too low.
the length of LED strip would require 3A.
« Last Edit: April 07, 2019, 02:11:58 PM by chenks »
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