My grandfather has a 1990 Chevy truck, 350, low miles (76,000). Naturally, it gets driven very little. Here's the problem: he has been through about 5 batteries in the last five months. He has had his starter checked, his alternator checked, and has made sure there are no lights getting left on. Any ideas what might be draining his batteries?

 

1st. you're sure the batteries are bad not just discharged?
2nd. a battery takes a while running at 55 to charge back up, if hes just going 5-10 miles every couple of days the battery never has a chance to charge up.

 

You need to do a current test when it's off. An amp meter in series with either battery lead can tell you how much current is being drawn when the vehicle is off. If standby current is much more than a couple of hundred milliamps there is a problem. Then you simply start pulling fuses and see when the current drops and troubleshoot that circuit. If you don't have access to a meter any repair place will do the test for probably a nominal charge