I really don’t understand why micro edged out mini, though, since they’re both so close to the same size, and hence suitable for basically the same uses.
One thing I’ve also discovered is that the cable can make a difference in the charging time–with the same charger.
A micro USB female connector is about 1 millimeter thinner than a mini USB one, it may seem meaningless, but it makes a world of difference in thin devices like cell phones.
Cheap cables may have thin gauge wires inside, even if the external thickness looks like any other cable. I’ve seen USB cables with little more than a few wispy strands of wire inside, not enough to carry the amount of current needed and the longer they are the worse it gets.
I think this may have to do with USB biasing VooDoo.
Since high-current charging was glommed onto the USB spec, there had to be some more-or-less backwards compatible way to tell the device that the charger could supply the required current. This was done by adding a resistor network to the data pins. When the device saw the correct voltage on the pins, it could enter high-current mode.
So, there are “charging cables” that have the correct biasing resistors in them, and those only match their mating devices. Some devices tie the data lines together, instead of using resistors, so if they don’t do it in the charger, you need a special charging cable.
The cables can make a huge difference
Especially the length.
I’ve bought a few USB charge meters like this:
It’s been very instructive. I’m not sure how I abuse USB cables, but they never seem to last for me.
Once you go over six feet it is very hard to find one that will sustain 2.1 amps needed for quickly charging an iPad.
You can find those meters for as cheap as like $10 and I’ve found them very useful in diagnosing various issues.