Wednesday, May 05, 2010 at 20:15
Be careful - 12.5V doesn't indicate the actual capacity.
For example, I have 2 ~40AH cranking batteries which have their expected 12.7V (after removing surface charge).
But they probably only have ~5AH of capacity. (They are 8 years old and have has a tough life!)
Although voltage is a good indication of how much of a batteries capacity remains, it is not a good indicator of capacity. (ie, 12.5V means ~80% capacity remaining whether that capacity is its new full rated or worn out capacity.)
The only way to be reasonably certain is a capacity test.
And yes - after standing, a heavy charge current is usually required - typically 20A or more.
And it may improve with cycling and high charge currents.
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