I had a 7' ground cable made and connected both battery's together, I assume because these are both new battery's that they are working 100% which is why it is staying at 14v or above I just drove it a couple miles since then, I think one of my old batteries is borderline no good the fans seemed to be putting a strain on the system and I have been having a problem with my old batteries holding a load after a couple of minutes with the key on it would tell me low battery but would always start fine the California heat just kills battery's I am going to take the old ones tomorrow or monday to be tested where I bought them and I bet they replace at least one of them