Zit Seng's Blog

A Singaporean's technology and lifestyle blog

Sad State of USB Charging Standards

DSC04779I recently bought this USB hub. I was quite excited about it, because I’ve been searching for some time for a powered USB hub that had a generous power supply. This amazing hub comes with a 4A (@5VDC) power supply adapter. The box also talks about how this hub supports the USB-IF Battery Charging specifications. Wonderful. It must be a pretty good hub that would charge my many USB gadgets.

Like my iPad, for example. The iPad is notorious for requiring lots of current on its USB input to charge its massive batteries. Many cheap USB power supplies would not support the iPad. They might be able to charge the iPad very slowly, but provided the iPad is not being used at the same time. It charges more slowly than it takes the iPad to drain its charge.

My new Epraizer USB hub boasts having two ports rated at 1.5A of output. Not quite what the iPad really wants (2.1A), but certainly more than many other USB hubs that don’t do more than 1A output per port. It should properly charge my iPad, right?

But alas, I found out things were more complicated. As wonderful as it is that this Epraizer USB hub supports USB-IF Battery Charging specifications, it turns out that the iPad does not support that standard. Apple chose to do something proprietary to its iPad. The Epraizer, I found out, did not support the iPad’s proprietary charging method, and would only charge my 3rd gen iPad very slowly, and not at all when the iPad is being used.


The Epraizer USB hub did seem like a good gadget though. It says it has over-current protection. The 4A @5VDC power supply does seem pretty generous, and is probably one of the largest, if not the largest, 5VDC power adapter I’ve come across. The box did not claim to support iPad charging, so I suppose they did not misrepresent its USB charging capabilities.

The sad thing is, a cheap 2-port USB charging adapter I bought online, too cheap to talk about USB-IF Charging Specifications and over-current protection, actually charges my iPad pretty well.

The iPad isn’t the only one doing proprietary USB charging. I’ve heard there are other tablets too. I don’t if this is a case of the current standards not catching up to the needs of new high-powered gadgets, or simply that manufacturers cannot be bothered with the standards.

I thought USB, and micro-USB, could be a very neat universal solution to connecting all our modern gadgets. Phones, tablets, cameras, and all sorts of other electronics. Today, new competing peripheral connect interfaces are coming up, including Apple’s Lightning and Thunderbolt interfaces, none of which are anywhere as universal as USB for charging purposes. So while Lightning and Thunderbolt are not threatening to replace USB as a charging mechanism just yet, they are certainly rocking the boat when it comes to peripheral connect interfaces, and that’s not helping us converge on some universal charging interface.

It seems such a shame that USB charging has become such a complicated affair.

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