My SL2 has 221,000 miles onit. I have had this problem for 2 years since I go tthe car. Periodically the redbattery light and the light next to it will flash together for awhile. Nothing ever happens and no one has been able to explain this. It happens more in cold weather.

 

Sounds like rotten/defective battery cables. Replace both the positive and negative cables, making sure the battery terminals are clean, and the connection points at the other ends of those cables are too. It is shocking what a little buildup of corrosion will do to an electrical system