I Have a 96 SW2 that goes thru batteries. The last 4 batteries have lasted from 6 months to 18 months. The battery in car now just died after 6 months. I have put a meter on the battery terminals when I get the car started. It is showing 15.2 volts. When I disconnect the positive terminal, the car continues to run. Am I getting lemon batteries or is the alternator overcharging? The batteries have been from Sams club - Energizer battery. Any help would be apprciated!

 

15.2 does seem to be a bit high -- unless you are in a very cold climate where charging voltages tend to run higher than the 14.6 or so seen by most people. Running the alternator "open-circuited" as noted in your thread will adversely stress alternators made after 1990. Take the car down to the local AutoZone (or equivilant) store, and ask them to check it out for you. Normally, they will do it at a "no-charge" price ....

 

Disconnecting the positive terminal in and of itself is not a valid test of anything. However, the reading expected to be achieved when an alternator is working correctly as stated by oceonarcher is generally 14.6 volts. If your reading is higher than that and you say it is and you are going through batterys I would say the regulator function of your alternator is bad and you need to replace your alternator.

However, your replacement frequency of your batteries is in part dependant as to where you live.
Here in Arizona where there is generally 1/3 of the year with temperatures greater than triple digits, the heat kills batteries like you would not believe,
I have not had one go bad after a year, but 18 months is not uncommon. But, the volt meter reading is 14.6 volts, not 15.2.

 

Thanks for the advice, I live in Florida, so cold is not much of an issue. I will take the car to Autozone and see if they can check the alternator for me.

 

Yep, sounds like a charging system issue to me.

 

+1 on the charging issue. That would be where I would look, like OceanArcher & Keith McClain suggested...take it to an auto shop that will test the output of your alternator. That may be the culpruit...

Side note on batteries...ever since my Wife got her 08 VUE the clock had been gaining time. A bit too much, in that she had to reset it often. One day last year her battery puked, and since she got the DiHard the clock keeps great time. Go figure...