Replaced my battery 6 months ago in 2010 Challenger r/t. Don’t drive the car allot so it sits and I start periodically. Drove a month ago and noticed radio buttons reset (like it lost power). Started right up a week ago. Yesterday completely dead. Tried to jump but it just setS off car alarm, fob would not even work to get in truck (did check and replace fob battery). Not sure how to jump start?