Powerbank with two different current outlets

[Flexbex]

Many powerbank come with two different outlets. Like 1.0A and 2.1A. what's the reason behind it? By USB standard shouldn't it limited anyway by charging and charged device?

[amyk]

That's presumably what the data lines advertise... which in cheaper units might not actually be what the output is capable of delivering.

[Flexbex]

Yeah but I wonder why they often have two outlets with different max amps? Is the 1amp more efficient? If it would be just for advertisement it would be advertised as having two outlets with both having max 2amps.

[wraper]

Yeah but I wonder why they often have two outlets with different max amps? Is the 1amp more efficient? If it would be just for advertisement it would be advertised as having two outlets with both having max 2amps.

Then it would need to be capable of supplying 4A total.

[Zero999]

Yeah but I wonder why they often have two outlets with different max amps? Is the 1amp more efficient? If it would be just for advertisement it would be advertised as having two outlets with both having max 2amps.

Then it would need to be capable of supplying 4A total.

Not necessarily. If each socket were rated to 2A, there would be no guarantee it's rated for 4A. It might be rated for 2A total.

Many powerbank come with two different outlets. Like 1.0A and 2.1A. what's the reason behind it? By USB standard shouldn't it limited anyway by charging and charged device?

I suspect it's an error. Does it say, which socket is which?

[wraper]

Then it would need to be capable of supplying 4A total.

Not necessarily. If each socket were rated to 2A, there would be no guarantee it's rated for 4A. It might be rated for 2A total.

Then it would not function properly if 2 high current devices are attached and customer likely will think their powerbank is faulty.

[Martin Miranda]

usb 1.0 is current limited to 500mA
usb 2.0 you can draw up to 5V, 1.8A,
usb 3.1 and with modern power delivery controller. voltages can go up to 20V @ 5A.

quick charge (power delivery) also requires licensing. power bank manufacturer will add that to the cost of the product.
but it's just about the PMIC ic. the more ports you add for higher power the cost will also get higher.

[Zero999]

Then it would need to be capable of supplying 4A total.

Not necessarily. If each socket were rated to 2A, there would be no guarantee it's rated for 4A. It might be rated for 2A total.

Then it would not function properly if 2 high current devices are attached and customer likely will think their powerbank is faulty.

If it was only specified to provide 2A total, the customer's expectations are faulty.

[wraper]

Then it would need to be capable of supplying 4A total.

Not necessarily. If each socket were rated to 2A, there would be no guarantee it's rated for 4A. It might be rated for 2A total.

Then it would not function properly if 2 high current devices are attached and customer likely will think their powerbank is faulty.

If it was only specified to provide 2A total, the customer's expectations are faulty.

And if you care about your name and product returns you would be dumb to sell something that likely will be misinterpreted by customers.

[Zero999]

Then it would need to be capable of supplying 4A total.

Not necessarily. If each socket were rated to 2A, there would be no guarantee it's rated for 4A. It might be rated for 2A total.

Then it would not function properly if 2 high current devices are attached and customer likely will think their powerbank is faulty.

If it was only specified to provide 2A total, the customer's expectations are faulty.

And if you care about your name and product returns you would be dumb to sell something that likely will be misinterpreted by customers.

And how would selling a USB power supply, with two sockets and a maximum total power rating of 2A be misleading?

One can buy a 1200W inverter, with two sockets, but only an idiot would think they can draw1200W from both of them simultaneously.

https://www.amazon.co.uk/BESTEK-Inverter-Converter-Outlets-Display/dp/B07V3DSDX1/ref=asc_df_B07V3DSDX1/?tag=googshopuk-21&linkCode=df0&hvadid=375433463703&hvpos=&hvnetw=g&hvrand=13717187046220011098&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006506&hvtargid=pla-821803257549&psc=1&tag=&ref=&adgrpid=79769156794&hvpone=&hvptwo=&hvadid=375433463703&hvpos=&hvnetw=g&hvrand=13717187046220011098&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006506&hvtargid=pla-821803257549

I've not counted the number of dual 13A sockets in my house, connected to the same 32A breaker, but I know it adds up to more than 32A. Perhaps I should complain to the builder (it's a new build) that the breaker keeps blowing, when I plug in three 3kW heaters? 

[NiHaoMike]

I have one that has a "1A" port and a "2A" port but they're electrically identical in how they're wired. Most likely it's so the product would sell to the average consumer who has a slight understanding of electrical ratings and thinks that they must use a 1A supply for their 1A device.

[PlainName]

thinks that they must use a 1A supply for their 1A device

That sometimes suckers me too 

But there are some products that rely on the PSU to limit current, and which may break or even burst into flames if you use a larger capacity supply. One I have is an electric screwdriver which comes with a 0.5A USB charger, and warning to use only that PSU. I plug it into a decent supply and it happily sinks 2.5A while charging. Considering it must be a small battery and is fully enclosed in the handle, that doesn't strike me as being particularly good.

[Psi]

It's probably more because various resistor values signify different standards that each have a specific maximum current.
So as an example.. This socket is for the LG 2.1A standard, and this other plug is for the Samsung 1A standard.

Also, the user may know they need a socket for their device that is "fast charge 2.1A"  but they may not know anything about how current works and so might think a 3A socket wont work because they need 2.1A etc..