USB socket Amp draw?

[robdav]

Hi

 

This is probably a dumb question but I thought I throw it out there.

 

If a dual USB socket has two ports, one labelled 5V 1A and the other 5V 2.1A is the maximum draw from anything plugged into the sockets either 1A or 2.1A respectively?

 

Thanks

 

Rob

[colin]

It depends on the usb charger, some can do 1+2.1, others can only do 2.1max. but even if it's 1+2.1 thats only around 1.5amp at 12v

[Derek Uzzell]

These links may be of interest

 

https://www.extremetech.com/computing/115251-how-usb-charging-works-or-how-to-avoid-blowing-up-your-smartphone

 

https://www.techadvisor.co.uk/test-centre/digital-home/best-usb-wall-sockets-3664216/

 

https://www.focus-sb.co.uk/blog/sockets-with-usb

[monique.hubrechtsgm]

They are at locations, some whit a amp rating indication, some are not. A dual amp fits a i phone or a ipad.

[colin]

Is it for laptop charging re your other thread? If so it requires a 19v usb charger which plugs into the usb c socket, but you need to check if your laptop is suitable, my latest Dell ultrabook can be charged this way.

[robdav]

No, just interested for power consumption purposes i.e. when charging a mobile phone if the socket says 1 or 2.1 amps is that all the phone will draw. Thanks for the responses.

[colin]

That should be all the phone draws at 5v, I use one of these https://www.tronsmart.com/products/ccta-quick-charge-30-usb-c-car-charger my phone is equipped with Qualcom quickcharge so can take 3amp.

[Kennyd]

In the case of the output you are talking about

I thought the max they could put out respectfully is 1a & 2.1 a

So if both were getting used to the max at the same time it would 3.1a draw

 

Maybe I’ve missed something?

[colin]

Kennyd - 2019-02-04 8:34 AM

 

In the case of the output you are talking about

I thought the max they could put out respectfully is 1a & 2.1 a

So if both were getting used to the max at the same time it would 3.1a draw

 

Maybe I’ve missed something?

 

As per my first post, some can output 3.1a, but cheaper ones can only output a max of 2.1a, so if both outputs are used one does 1a t'other does, 1.1a.