kenny, I have to agree with Patricia, prs505 is not a clie. For some reason, Sony implemented a very strict spec for the USB which demands a "host" or attached PC before it starts charging. It needs to do some negotiation before it starts up.
But I've been thinking, I use a
hacked cable to charge my Nintendo DS on the road using a USB charger, why not hack the barrel tip of a PSP charger and splice that into a USB cable (first grounding the data lines of course, like I did with the USB cable I use for my DS). It would be no different than
this cable mod for the PSP itself.
In fact, I think I will try to assemble that this weekend. I have a 3-week holiday in Thailand coming up and I would love to take just the one USB charger for my blackberry, DS, and PRS-505.