You can search this site and download the manual. I would first of all guess you fried the regulator but before I jumped to that conclusion I would install a properly charged battery in it to see what you get. If nothing check the main fuse and the ground wire to the frame to see if it melted in-two. Since the unit was wrecked there is a chance that some crucial wires are broken or grounds separated so verify those basics first. When you install the battery and hook it up the first time, install ground cable first and then before you put on positive cable use a voltmeter to see if there is any draw to alert you to a parasitic drain.