There are two 12mm hex head screws and 9 tack weld points holding the metal battery tray to the frame. The tack welds are a little smaller than a number 2 pencil eraser...and they are incredibly strong. The weld points are difficult to locate due to the battery tray having a contour that follows the car body. What I did was start by removing the hex heads, then pry between the frame and the tray (with a long shanked flat-head screwdriver) traveling clockwise. A grinder isn't good here because of the curvature of the tray. After I got a gap pryed away, I placed a hacksaw blade (one of those straight handled hacksaws) in the gap and began sawing the tack welds. Then, pry some more, then saw....and repeat all the way around. There's not much to damage underneath as long as you keep the saw strokes short ( your brake lines aren't far away, but fortunately they run through the frame). You'll probably have to loosen the fuse box bolted up against the passenger fender for clearance. The horn for alarm is under there, but its not really in the way. I wish Nissan had bolted this tray in place instead of welding it. Took me about 2 hours to get it out.