I have a 2004 5.9 HO 2500 quad cab. How long should two fully charged yellow top optima batteries last without driving the truck. Sometimes I can get 2 weeks or as short as 1 1/2 weeks without driving truck. After 2 weeks batteries are dead. Normal?

 

First WELCOME to DTR!!

Second. You must have a draw on the batteries or weak batteries. You should be able to let it sit for a month with no issues. Actually even longer but if you are only getting 1 1/2 to 2 weeks you have other issues.

 

yeah you definitely have something drawing power from the battery. I've let mine sit without starting for 5 months (due to tranny issues) with Deka 60s and it started up as normal

 

Any suggestions on how I can find out where the draw on the battery is coming from?

 

With one battery disconnected, and your ammeter connected between the + post and the disconnected positive cable on the other battery, you will probably have a parasitic draw of as little as a third of an amp...Remove fuses one at a time to tell which circuit has the draw...Start with add-on and none-OEM circuits first......Ben