I had a group 37 or whatever (60lb agm) under the passenger seat when I needed exhaust done on the CJ5. I guess the positive post found a spring when the guy went to move it in for the night. They saved the seat but kindly asked me to fix the battery and wires before he could work on it. That makes a hand crank or blank shot gun shell sound a lot safer than this new fangled electric stuff. But I do have a lot more respect for batteries now.