How do I recharge MP3? Do I just plug it into USB port to recharge. Do I need to replace battery after 8 hours of play?

Taken from the Quickstart User Manual

LED Light 1 (L1) - is by the earphone socket
LED Light 2 (L2) - is by the USB connector

Charging: Please switch on the player before charging. (Push the on/off switch to 'on' )

When charging the battery for the first time it is recommended that the player is charged about 8 hours. Connect the player to an active USB port using the supplied cable. The computer must remain on during the charging process.
Recharging: Recharge the player will take about 3 to 4 hours. When it's charging, L2 will turn on in red, when it's fully charged, L2 will turn to green light.
When playing music, L1 will shine.

The rechargeable battery in the MP3 player needs to be replaced.

Most media players have a rechargeable battery and it is charged by connecting the media player to USB cable and then plugged into the USB port on a computer.

Hi
Check the Manual
User’s Guide


Hay Don't worry it will work
Note: Some low-power USB ports may not be able to provide enough
charge power. Also note that rechargeable batteries may
eventually need to be replaced as they have limited charge
cycles (which vary with use and settings).

Li-ion Battery
The Sansa e200 MP3 player comes with a replaceable and rechargeable
lithium ion battery. To use the player for the very first time, remember to
fully charge the Li-ion battery. You can charge your Sansa through the USB
port of your computer, a car adapter (not included) USB port, or AC adapter
(not included) USB port.


Please execute the following instructions for charging the battery using
an USB port.
1) Connect the smaller end of the USB cable into an available USB
port on the computer
2) Connect the larger end of the USB cable into the dock connector of
the player
3) The computer must be on for most USB ports to charge your
battery. Your Sansa will show connected and the yellow charging
indicator will appear. The battery level indicator will blink while
charging. You will not be able to play while connected to the
computer USB.
4) To stop recharging, disconnect the cable.
The battery can also be charged using an AC adapter (not included) or
a car adapter (not included) and you will be able to play your device
while charging with one of the adapters. The battery will reach
approximately 70% charge in 2.5 hours and full charge in about 3.5
hours. It is recommended that you fully charge your Sansa e200
before the first use.

Coby MPC7085 requires a 12 hours charge when used for the first time.
Always use a direct connection to the computer when charging with the USB cable: a hub or cardreader should be self-powered.
See page 12 of the manual:
http://www.cobyusa.com/files/manuals/MPC7085_MN.pdf

http://www.sandisk.com/media/175960/clip_um_0608_eng.pdf

Windows XP SP2
• Windows Media Player v10
• Intel Pentium class PC or higher
• CD-ROM drive
• USB 2.0 port for hi-speed transfers and charging

Make sure HOLD button is not on.

Battery
The Sansa
®
Clip player comes with an internal rechargeable battery. To use the player for
the very first time, remember to fully charge the battery. You can charge your Sansa
®
player through the USB port of your computer, a car adapter (not included) USB port, or AC
adapter (not included) USB port.
Charging
To charge the battery, please follow these steps:
1. Connect the larger end of the USB cable into an available USB port on the
computer.
2. Connect the smaller end of the USB cable into the Sansa
®
Clip player.
3. The computer must be on for most USB ports to charge your battery. Your
Sansa
®
will show connected and the yellow charging indicator will appear.
The battery level indicator will blink while charging. You will not be able to
play while connected to the computer USB.
4. To stop recharging, simply disconnect the cable.
The battery can also be charged using an AC adapter (not included) or a car adapter
(not included) and you will be able to play your device while charging with one of the
adapters.
NOTE: Some low-power USB ports may not be able to provide enough charge
power. Also note that the rechargeable batteries are not replaceable.

I have the same player. You can use a rechargable battery. But you cannot charge the battery by connecting it to the USB. You must charge the battery with a AAA battery charger - they sell them at walmart for like $15. The rechargable battery really works excellent in this player - I listen to my player all day long and rechargeable batteries are the only way to go for me! Make sure you have four batteries though so you can always have a backup charged as the charger takes 8 hours to charge the batteries.

Make sure the hold/lock is not engaged- it will prevent the player from charging.

If you are referring to the Sansa Clip, then you must connect the mp3 player to the computer using the USB cord - make sure that your computer has a USB 2.0 port, or it may not have enough juice to recharge the player.

the rca pearl does not have an external power source, only the AAA battery. Just put in a new AAA and you're good.