Quote:
Originally Posted by Fortissimo
Why not? I've seen a lot of recommendations for blackberry chargers. If I'm not mistaken, they are rated at 700mA. Also, I believe I read somewhere that when charging via a PC, the PC only supplies about 500mA.
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PC ports are indeed limited to 500mA, that's why the new charger spec has the data leads shorted, as this tells the device that it is connected to a dedicated charging device and can safely draw more charging current than the standard 500mA allowed by the USB device spec.
Based on the time to full charge, the current being drawn by the PRS-350 and PRS-650 are probably below the 700mA blackberry chargers limit, but I wouldn't go below that with something like a 500mA charger, because devices that signal that they are chargers instead of PC ports need to support higher charge rates.
This was a compromise to allow faster charge times for cell phones without having to up the current spec on all PC side data ports (which would not have been compatible with older PCs).
This is one of the reasons that the Sony is so fussy about seeing the proper signal that it is connected to either a dedicated USB charger or a PC port.
It will charge at 500mA or less on a PC port and a little more on a dedicated charger, but if it can't tell what it's hooked to (as is the case for some older Apple chargers) then it will give up and pop up a message saying that it can't charge.