Should You Charge A Phone Via USB?

It may seem redundant to use a wall charger for your smartphone when you could just use a simple wire to plug into your computer – but if you want the fastest and most efficient charge, it’s not that simple.

First of all, the maximum amount of power your cell phone will accept at any given time is 2.1 A. Any device that offers more than that will be splitting the charge between multiple devices, slowing it down.

There are 3 different types of USB port. USB 1.0 is relatively uncommon nowadays – it does not support device charging, but can deliver a meager 0.5A. USB 2.0 is the most common, and can draw as much as 1.5A of power. Far less common is USB 3.0, which is capable of drawing 5 A of power, but like USB 2.0 it is configured to stop at 1.5A.

In terms of charging, the type of port is not as important as its designation. There are three: a standard downstream port, a charging downstream port, and a dedicated charging port. The ones on your computer are most likely one of the first two. A USB 1.0 or 2.0 standard downstream port can deliver 0.5A, but if it is USB 3.0 it can deliver 0.9A. Charging downstream ports can deliver up to 1.5A. Dedicated charging ports are usually found in wall chargers – and although the standard is still 1.5A, you can find a wall charger that will deliver the maximum 2.1A.

cell phone charging

So, should you charge your phone via the USB on your laptop? Well, that depends on the type of USB – and it can be hard to tell. It also depends what type of wall charger you use – as mentioned above, many still deliver the same amount of energy as a computer would. Try the different USB ports on your computer to see if one is faster than the others – one may be a charging downstream port rather than a standard downstream port. But even if your computer does deliver the maximum 1.5A when you charge a phone via USB, it will not be able to deliver the maximum 2.1A that some wall chargers can. All of our cell phone chargers use dedicated charging port technology in order to deliver the maximum 2.1A to each device – even when more than one is plugged in. Check out our selection of cell phone chargers!

Source:Extreme Tech, Wikipedia: USB

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