Well ive been driving my car forever and out of no where as i shift into higher gears prolly around 3500rpms the battery light comes on the dashboard. Then today i was driving it wouldnt go off at all and its doen that before but it died completely no speedometer random lights on the dash lighting up such as oil light seatbelt ect. The heat shut off everything just went down. My question is what could cause this problem. My battery is brand new only 6 or 7 months old. Please someone help

 

Could be the alternator..

So,, it doesn't crank either..correct? Once the engine dies..

If the alternator fails, the vehicle combined draw including all the accessories will run the battery voltage down until the car dies.. Anything that has a large amp draw will generally not work once the battery goes flat.. Easiest thing to do, would be have someone (may need to jump start it) test the running voltage across the battery terminals.. Easily done with a simple volt meter.. Or, fully charge the battery up, and drive it to a 'near by' shop or possibly a parts vendor like Autozone, NAPA ect. and most will check the charge rate for free..

Know anyone with a volt meter??