I assume you are using robotC:
You have to edit the Vex Competition Includes file, by doing a save as into your project folder under a different name, and then including that file instead of the original competition includes file. You then change the line at the start of the main() function from displayNextLCDString(“Startup”); to displayNextLCDString(“Your text here”);
The batteries are not overcharged. Most all batteries do this. For example, a standard automotive battery is 12 Volts, but a full charge is somewhere in the neighborhood of 13 - 13.5 Volts. If your 7.2V battery gets somewhere close to 8V or above then you should be worried.