The 503G has a 10-pin miniUSB connector, which means your provided AC adapter chargers very quickly, but it also means that when you use a regular miniUSB charger (ubiquio 501 or other brand), it will take several more hours to fully charge the device and you have to keep it off or in sleep mode. If you have regular miniUSB accessories, you can certainly use them, you just need to expect that it will take longer. One solution we've developed is an adapter http://www.mobilepla...p.aspx?i=154871 that will allow any standard (5-pin) miniUSB chargers, like those that come with the 501, to charge the 503G (and other 10-pin devices). Those will also be available in a couple of weeks.
We do have ORA chargers listed as well, which will ship with the adapter, simply enter "ORA 503G" in the search engine for a listing of all ORA accessories for the 503G.
Quoted from Expansys forum