Re: Batteries or Alternator?
If you have one or can get your hands on one, locate a DC amp clamp meter and connect it to the positive battery cable on the passenger side between the pass side battery and the starter solenoid and see how many amps are being drawn with nothing on in the truck and the doors closed and underhood light off. If it is less than an amp you don't have parasitic drain. How old are your current batteries?
97 F-350 XLT CC DRW 4X4 PSD, 285/75-16 Custom bumpers, Gauges-boost/egt/trans, Swamps IDM, 3.5"dp- 4" exh., 3" Body lift, ES bushings/mounts, Built trans, billet conv, B&M pan, Hayden cooler, Adrenaline, stage 2's, IC, H2E, E-fuel
ARP's, 910's, Smith Bros. to come