The take away is that always, once past 80% state of charge, the battery acceptance rate and time determine how close you get to a 100% state of charge, on a daily basis.
That should be the goal, daily, to restore as close as you can, as best you can, a 100% state of charge, with all the charging systems you have available to you. It will require adjustable voltage charge controllers, and it will take voltages a lot higher than the battery maker attorneys are willing to insure.
But my take, like landyacht318's experience has been to bump the voltage, but be mindful and respectful, and monitor what you are doing, until you know what you are doing, to top charge, and to equalize charge to recharge the slacker weak sister cell to whip 'er back into shape and pulling more of her own weight.
Specific gravity readings only, will tell you when you are at 100% state of charge. All cells uniform at a specific gravity of 1.275 or slightly higher. Battery voltage readings are completely unreliable, only a guideline to be met when top charging or equalize charging... a goal, but not an absolute, to insure 100% SOC. Dipping and Specific Gravity readings never lie. They are absolute fundamental laws of chemistry, physics and mass.
This is all in reference to flooded lead acid batteries.
