battery problem

My nephew has a 93 which has taken to blowing the top off of his batteries. two so far. Just wondering if anyone else has run into or has any ideas what is causing this. I have checked for loose connections and grounding problems and have not located any. I never had this problem on my 91 and am running out of ideas.

Thanks

The most obvious problem I can think of is the battery is being overcharged. The voltage measured at the battery terminals should be on the order of 13.5 to 14.0 volts while the car is on, about 12.5 volts when the car is turned off. I do not know the exact range, but you can check out another car and see how the voltages are when that car is on and off.

If the voltage is higher than 14 volts then I would suspect an alternator/voltage regulator problem or associated wiring.