Thread: Battery Question

Originally Posted by MDCrappie

But you see what you are ASSUMING is that the 12.5 is what the battery "is charging to". He did not say that. He said " They are several years old, but the other battery still charges and shows 12.5 volts". Now if that 12.5 is immediately after removing the charger (which is not the correct way to check a batteries voltage) then you would be correct. If that 12.5 is after he has removed the float voltage then that battery is NOT shot and likely still has plenty of life left. Hence my comment of "Need more information before making assumption".
BTW - I'm not confusing anything, I'm just not making assumptions with too little information.

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.

Originally Posted by CatFan

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