[MacGyver]

Is the Optima the same height as the other battery? The difference in size may be pulling on the cables differently. We had one at a show last year that had the cable pull out of the end where it was bolted to the frame under the trunk. Might be wise to tug and check the cables. We figured it out by using a test light from the pos terminal to the frame with the suspected battery in place and found no current to ground. Checked further and found the loose ground cable at the terminal crimp at the frame. Worth checking just incase.