That sounds like a distinct possibility Exec_Plat. I thought the OP had tried a different cable, but I just reread the thread and I don't think that's the case, so the cable is definitely a possible culprit here.

In the very old days, USB provided one type of power, generally up to a specific amperage, so many USB power ports these days are in fact quite "dumb" and don't communicate with the device to negotiate power levels, they just supply power and are done with it. In other cases, they are smart enough to identify themselves, but devices are picky and only want to draw power from certain sources–when they see the power port, they say "hey, he's not on my trusted list, so to play it safe I won't draw any power from him." That's where it can help to put in the little white piece I mentioned above: it takes a port that will communicate and turns it into a dumb port that won't, which for some devices will enable charging when it would otherwise block it. Ultimately this comes down to some power ports being stupid when they should be smarter, and some gadget manufacturers trying to protect their hardware by insisting that only some kinds of ports charge their kit since they know how many ports out there don't conform to the specification. It's a real chicken and the egg issue.