Hi, Since my original post, I bought the Coby MP620-4G MP3 player. The OM says to use a "high power" USB port (computer). There is no other information in the OM or at their web site on a recommended charging current if using a different source.
I can set the maximum current limit on my lab quality regulated power supply. Note: There is no connection to the USB "data" pins with this setup. The MP3 player display indicates that it was "charging".
When I first charged this MP3 player at 200 MA max, which didn't take very long before the display said the battery is "charged", I loaded it with several hundred songs (MP3). It played for a little over an hour then the player "died" (no warning).
I recharged it at 100 MA max and it played over 5 hours, but I didn't run it until it "died". Again, when I charged it at 200 MA max, which didn't take long, it played for 1hr and 10 minutes, then "died".
For the second time, I charged it at 100 MA max, and it plays a long time.
John
PS, Remove "ine" from my email address