I would suggest getting an Apple USB power adapter and a cable with a USB end and a DC end. The Apple USB power adapter can be bought on ebay for about $10. It's the size of an ice cube so very compact and good for travelling. Get a USB to DC port cable and you can plug it into the DC port of the PRS-505. This means you'll be able to read and charge at the same time.
Note, if you do get the Apple USB power adapter, buy one with the green dot. Apple made a recall on earlier models. Those are the ones without the green dot. If you buy the power adapter from Apple's store, it'll cost you $30 which is too expensive. Buy it from eBay.
|