The optima batteries are 6 years old and just could not crank the v12 over fast enough to start the engine. This is the second set of optima batteries I have had in my pierce, and the last ones I will buy. They seem to go down fast and then take two days to recharge. One day to get to 75 percent and then cool then the next day to get up to 100 percent charge. I had them hooked up to add more CCA . In the years I have gone through 4 optima batteries my son in law has the same Napa 6 volt in his series 80 that is totally reliable. Just time to try a different approach..