Intermittent Clock, Radio & Uconnect Operation

[Cloudmaster Don]

Puzzled by this anomaly, I thought it might be a ground problem. Other than a loose battery cable, I couldn't find one. Tightening the loose cable made no difference as the system would work for about three engine starts, then would not work for five or six starts, (no change). Kinda hard to listen to the radio or take hands-free calls. Then, I realized I might have a dying battery. Voltage was OK, so I got it load tested and found one bad cell. Replaced both batteries and haven't had the inop clock, radio nor Uconnect problem since. Whaaat?! Can anyone explain this to the electrically ignorant (me)?

Cloudmaster Don