I have a 2000 silverado 1500 that I have had for quite some time that I used to daily drive but the past couple years I rarely drive it due to getting a new truck. Decided to keep the old one for a backup/beater rig but I swear the thing goes through batteries like crazy. I have an interstate battery in it that is about 4 years old and dead as can be. I jumped it this evening and let it run for about 20 minutes and tried to start it and dead again. The volt meter shows it’s charging where it always has since I have owned the truck. No battery light or anything to that nature. Could it be the alternator not putting out the correct amount to charge the battery or is the batteries just getting ruined from setting around and rarely being driven?