x2 on Jerry's mention of the constant charge ammeter reading. Also if you happen to have bought one of Wal-Mart's most inexpensive batteries, please be aware of a couple of things: 1...they are okay as today's auto batteries go (not nearly as good as in the past but fine for the cost) and 2...very important...you may have a battery that just like its elder relatives needed the water level checked regularly. And this may have become sort of an unexpected maintenance routine as most auto batteries don't require it any longer. Fill it as you always did (up almost to the little split part of the internal fill well thing) and use distilled water if you have it.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end