shmkr,

A functioning charging system will show 7 to 7.4 volts or so at the battery when the engine is running around 1500 RPM. This is what it will take to keep a 6 volt battery fully charged.

I have enclosed a nice link to a bunch of wiring diagrams. Find your year and click on it. If you have lost 4 batteries in three years you surely have a problem. Keep in mind that overcharging can kill a battery the same as a constant discharge/recharge condition.

There are very few fuses on these old rigs, so any external drain on the battery would have to be of a high resistance or the truck would probably have gone up in flames long ago.

If the battery is in a compartment under the floorboards, look for telltale signs of gassing. This would be from overcharging and would show up as a white crust in the area around the battery.

The voltage regulator controls the charging system, and if you are overcharging the battery, this would be the prime suspect.

Take a look at the wiring diagram and see if it helps.


http://chevy.oldcarmanualproject.com/electrical/wiring/index.htm

Stuart