13.1 is a little high depending on what kind of battery it is. Maybe your voltage regulator is bad...If you have someone hold a dmm on ur battery, then rev your motor, if the voltage keeps climbing as you rev, your regulator is bad. You might be sending 16 plus volts into your car/electronics, I would check it asap //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif