I would like to thank Corvette Forum members who replied to my post about a battery for my 89 Corvette. I was away when the responses arrived, and I could not acknowledge all of your suggestions directly. I would like to thank 89 Paul, bogus, westifer, tacblu, and 89x2 for their suggestions.
I decided to try a Sear’s Gold Diehard. The total cost, including about $25 for what they call a difficult installation, and tax, was $120. They wanted to remove the side panel, but with all the battery changes I have made, I told them to remove the support strut and gently put aside the cruise control. I had to sign a waiver. Once they found the right sized socket driver, it went real fast.
I was somewhat disappointed to see a battery voltage maximum of only about 12.2 volts even after a long trip. This is the ignition on voltage, but no cranking voltage. While driving, the panel voltage goes up to 14.5 and decreases to 13.8 as time goes on. The voltmeter on the instrument panel is accurate. I have compared it with a voltmeter. I have measured a different battery with a voltmeter, and it shows 12.9 volts resting. The battery voltage drops anywhere from 0.3 to 0.7 volts while cranking. I haven’t looked in the repair manual yet to try and find out where the voltage is measured. I notice that the battery voltage will come off its peak by about 0.1 volts per day if I let the car sit. This is without activation of the Viper alarm system I have in the car. I haven’t let the car sit for more than 4 days since I installed the new battery, but I am on a 9 day trip, and when I get back I will find out how it held up. By the way, Sears did not do a test of the alternator, or anything else. In spite of what it states in their work order; they simply replaced the battery. However, I believe the charging system is ok. There may be a heavier than normal drain on the battery while the ignition is off. It is one thing I will measure if this battery doesn’t hold up. I have a ride control module in the car which may make the load greater than other 89 Corvettes.
I am now back from my trip, and I am glad to say that the ignition on, without cranking voltage, was 11.8 when I returned from my trip. That was more than enough to easily start my 89, which it did. It seems the Sears Die Hard is pretty sturdy. Thanks.

 

I've always had really good luck with the Die Hard too.

 

any time! glad we were able to help!

however, you have a low grade drain condition... If I remember correctly, the voltage drain on a Vette, with "everything" off is about .25 volts. over that, something is killing you.

I would also make sure the charging system is in shape.