Dead Battery

If your car cuts off while driving due to an electrical system failure, your problem is probably not the battery. In most driving, the alternator provides full power to run the vehicle although it may borrow power from the battery while stopped in traffic, particularly if the air conditioner or other high power use items are on. The car should be taken to a place where the battery and charging system can be tested. Most quality auto parts stores can do a computer diagnostic that will tell you if a low battery is still good and merely needs charging or if it needs to be replaced. If you go to a good auto repair shop, the battery will be tested and charged if needed before the charging system is tested. Unless a good, fully charged battery is in the vehicle, an adequate charging system test cannot be done.