Thread: Batteries
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Old 09-12-2017, 06:57 AM   #19
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City: Casco Bay
Country: USA
Join Date: Feb 2016
Posts: 230
It is entirely possible, and quite likely, that 4 year old flooded G-24 batteries are at end of life, especially if they have actually been deep cycled.

In the flooded form factors of G-24, 27, 29/30/31 and most 4D and 8D batteries are really more of a dual purpose battery yielding less real world cycle life than a battery specifically designed for deep-cycling purposes, even if the label says "deep cycle"...

What is a Deep Cycle Battery?

Also please don't be lulled into the understanding that a specific gravity test can tell you much about the state of health of a flooded battery. All an SG reading can tell you is the batteries state of charge or a cells SOC. You can also derive battery SOC from a resting open circuit voltage reading. SG is best used to discern cell imbalances and to help determine equalization schedules..

Even a battery suffering a 60% loss in Ah capacity, eg: 100Ah battery delivering just 40Ah's, can still put up a good SG reading. It's entirely possible, I see and measure it regularly, for that 100Ah rated battery to deliver a perfect SG reading when it can only deliver 40% of its original Ah capacity.
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