The original battery went bad when the van was 3 years old (2017) This battery is almost 3 years old.....Its one of those large AGM type battery. Do they not last any longer than that?

No check engine light and this does not have a voltage gauge. Apparently does have a battery light. So no warning lights on.

67 Charger 383 auto
75 Dodge CNT 800 CAT Diesel
2012 Ram Crew cab 5.7 4x4