Swapping input from mains plug to USB

[TheDrownedApe]

Quick clarification required please as Google wasn't forthcoming.

I have some under cabinet lights powered by mains plug into transformer. I want to swap the plug end for usb. Transformer states max I/P normal uk spec and O/P 12vdc and 5w.

USB will be 45w and i'm assuming this won't be an issue?

[ooo000ooo]

Is USB not 5V?

[Mr Pointy]

USB output is 5V though, not 12V.

[TheDrownedApe]

OK thanks, glad i checked. Ugly plug it is then

[tendown]

Usb is 5v, except when it's 9v or 12v or 20v.

This will give you 12v out of a usb c socket - provided the usb outlet is capable of giving 12v (not all are - if it is advertised as suitable for charging a laptop it will)

https://thepihut.com/products/12v-5a-usb-c-3-1-pd-...

[Ham_and_Jam]

TheDrownedApe said:

OK thanks, glad i checked. Ugly plug it is then

Swap the socket to one of these with built in USB-

[Evanivitch]

ooo000ooo said:

Is USB not 5V?

USB-C Power can be upto 20V, and some will deliver 12V. Typically 5-9-15-20.

[TheDrownedApe]

Ham_and_Jam said:

Swap the socket to one of these with built in USB-

that's very close to what i am buying today (but in nickel).

https://www.bgelectrical.uk/uk/wiring-devices/nexu...

But it is 5v-12v output from USB - does this mean it can go upto 12v if the demand is there?

[Mr Pointy]

Evanivitch said:

ooo000ooo said:

Is USB not 5V?

USB-C Power can be upto 20V, and some will deliver 12V. Typically 5-9-15-20.

Doesn't it require the receiving device to indicate what voltage it would like to receive though? I doubt a string of LED lights has the signaling data chip, although I might be wrong.

[Griffith4ever]

TheDrownedApe said:

Ham_and_Jam said:

Swap the socket to one of these with built in USB-

that's very close to what i am buying today (but in nickel).

https://www.bgelectrical.uk/uk/wiring-devices/nexu...

But it is 5v-12v output from USB - does this mean it can go upto 12v if the demand is there?

No, voltage is fixed, unlike current. Current is demand based , with supply limited. Voltage is fixed. Your USB outlet would need to offer 12v, and those wall ones don't. They are 5v.

I believe you are looking for a USB supply with 12v trigger, and it looks like they are power bricks for specific applications, like laptops.

The one you linked has its spec on the front. 3.1a @ 5v. So that means max 3.1a, always at 5v (15.3w max)

Edited by Griffith4ever on Wednesday 30th October 09:12

[TheDrownedApe]

Griffith4ever said:

TheDrownedApe said:

Ham_and_Jam said:

Swap the socket to one of these with built in USB-

that's very close to what i am buying today (but in nickel).

https://www.bgelectrical.uk/uk/wiring-devices/nexu...

But it is 5v-12v output from USB - does this mean it can go upto 12v if the demand is there?

No, voltage is fixed, unlike current. Current is demand based , with supply limited. Voltage is fixed. Your USB outlet would need to offer 12v, and those wall ones don't. They are 5v.

I believe you are looking for a USB supply with 12v trigger, and it looks like they are power bricks for specific applications, like laptops.

The one you linked has its spec on the front. 3.1a @ 5v. So that means max 3.1a, always at 5v (15.3w max)

Edited by Griffith4ever on Wednesday 30th October 09:12

darn it it opened on the wrong socket. the 45w 2 gang says 5-12v

[tendown]

If you get the wire I linked and plug it into the usb c hole on that faceplate, you should get 12v. It has the electronics mentioned to "request" 12v rather than 5v

[TheDrownedApe]

tendown said:

If you get the wire I linked and plug it into the usb c hole on that faceplate, you should get 12v. It has the electronics mentioned to "request" 12v rather than 5v

super thanks, saved me some soldering time

[egomeister]

What products are you actually using?

Edit: Just seen tendowns posts - as said, trigger cable is your best option if suitable

Edited by egomeister on Wednesday 30th October 09:51

[TheDrownedApe]

egomeister said:

What products are you actually using?

some old junk i bought on a Wickes clearance event a couple of years ago that i couldn't sell on, only cost me a fiver!

wickes avi colour controlled led kit - google doesn't have the result

I don't want the colour changing but i'm renovating my utility room and adding a flashy splashback to hide to some dodgy plastering from when i ripped out the old tiles.

the white light will, hopefully, make the splashback look better. it

[Griffith4ever]

TheDrownedApe said:

darn it it opened on the wrong socket. the 45w 2 gang says 5-12v

Perfect!