I purchased a used 2015 RT Plus about a month ago. It only had 3,200 miles on it and an in service date of 6/16/2017. Before starting ,the voltage is around 12.4 volts and running it is 14.2 volts. Tonight I noticed the running voltage was about 13.8 volts ( It was night time with lights and a/c on). Kind of worried about the battery getting to the end of its life expectancy. I know the battery will be under warranty till 6/16/2020 but don't want to get stuck at a bad time. I did check with my Fluke to make sure the cars gauges were correct.The jump pack will have to travel around with me for piece of mind and I guess I need to make a trip to Advance to see how the battery tests. Just wondering what other Challengers voltages are running.