Years later, but i interest in this thread. My mp4 player battery usually last 5-6 hours. I know some info about making mp4 player battery last from the net, share here:
1. Set your players LCD set to 'Dark Mode' in the setup menu. Have it go to dark mode after 5 seconds (or 10 if you'd like). You DO NOT want to put it on gray mode, which is the default mode the player comes in. Because the screen is on constantly, this literally drains your battery away.. like a leech! With dark mode, the screen will shut off after the amount of seconds you specify.. but the player will still be on. Much like Ipods, eh?
2. FULLY charge your
mp4 player battery. All of these players come with a charger. When the green light is on, that means it is charging. When the green light goes off, it is SUPPOSED to be done. But, it is not. For some reason, the charger won't charge the battery fully in one go.. and I don't think anyone knows that, because I haven't seen it posted before. But, after your green light goes off the first time, push any button on your player (just not the off button!) and you will see the green light go on again. It will then fully charge the rest of the way.
3. Do not leave the player in any abnormally hot or cold places. Leaving your player in the car on a hot summer day is a really bad thing to do, because there IS acid in those batteries, which could cause them to explode, if there are in a very hot or cold area. That is the worst-case scenario. Most of the time, the battery acid will leak and it will cause damage to the other components, making your player inoperable.