Quote Originally Posted by CatFan View Post
A battery that is at 12.5V after charging, regardless of whether surface charge has been removed or not, is junk. 100%. The excess internal resistance and low specific gravity results in dramatically reduced capacity and charging issues.

If a battery can’t reach its designed full charge voltage, it has suffered chemical or physical damage. Battery full charge voltage doesn’t decline with age. Even a very old battery with very little remaining capacity will still reach and hold its full charge voltage if it’s not been damaged from neglect or abuse.

It’s even worse than junk, because the lower voltage results in charger current and voltage remaining high leading to bubbling electrolyte for far too long resulting in extreme water use, heavy gassing and acid damage to the area around the battery. These are the batteries that explode because they are run dry.
OK, you win......go sell some more batteries. I've been running a 10 year old Interstate Group 31 for the past 5 years at 12.5 volts. It powers my electronics (Elite7ti and Garmin 7cv, livewell pump) as well as my Riptide trolling motor. It was also declared "dead" by the mechanic at the marina 5 years into it's life, and I got it free. Crazy thing it that it has NEVER once let me down during the past 5 years. Maybe I should replace it now? Nah