I purchased my 3500 new in Jan 2020 and it was built in Oct 2019. The twin batteries died and were replaced at the dealership under warranty in Nov 2022. That's about 3 years. Could I be safe to assume that I will not have to replace them again until early next fall--which would again be 3 years?
I did purchase an extended factory warranty out to Jan 2026, and am far from the 75K mile limit. That warranty should again cover batteries. Should I keep the current batteries until Jan 2026?
AS far as assuming how long batteries last, that is a shot in the dark. Check them, keep an eye on them, and if you start seeing tell tale signs of battery issues, I would not wait, replace them both. On parallel systems, never replace just (1). The average seems to be around 3-4 years, but that is also dependent upon use, health of vehicle charging system, environment used (ie heat/cold), possible batteries discharged too far (say leave on lights), and on and on, really just too many variables.
Your extended warranty probably does not cover batteries, unless you got some other 3rd party warranty and it explicitly says they cover batteries. If it is a Mopar Maxcare, it does not cover. You may have some type of warranty ref the batteries on purchase like a pro-rated period, but a Mopar Warranty in itself does not cover batteries: Excerpt below from My Maxcare: (U may want to pull out yer extended warranty and read what is listed under not covered items). Just saying.
PART OF LIST ON NON-COVERED ITEMS. FROM MY ZIEGLER MAXCARE DOCUMENTATION:
• Battery and cables; any battery for a component; spark plugs and wires; lights (bulb, sealed beams, lenses);
suspension alignment; wheel balancing; wiper blades; catalytic converter, particulate filter and any other exhaust
system components; heat shields and exhaust hangers; throttle body cleaning; evaporator deodorizing; carbon
cleaning;
• High voltage battery is not covered at any time (regardless of cause of failure)
