AGM Battery

[Gros Ventre]

Installed a voltmeter on my truck. In observing it, just a day now, it is following the pattern of voltages I expected from a Flooded Cell Battery. When cold this morning, it came up at 14.9VDC and then slowly declined as the engine and compartment warmed up. It steadied out at about 13VDC. Interesting, and more to follow as I observe it. The logic to this is simple: the chemistry of the AGM battery is the same as a flooded cell type. Lead, lead oxide, in Sulphuric acid. The electropotential of the cells remains the same regardless... So we'll see what gives.

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[Gros Ventre]

Some background. In a large flooded cell battery there is a relation called TVG. This stands for Temperature-Voltage-Gassing. It turns out if you cram too high a current into a lead acid battery it produces so much gas (some gas is always generated when charging) that the bubbles can spall off active material. The TVG relationship limits charging rate relative to temperature in order to minimize loss of active material. The plates in an AGM battery are much thinner that a flooded cell battery. So I infer that the chargers for an AGM battery limit charging rate in some way and then full charge voltage to prevent such action. At the end of the day the electro-chemistry remains the same in either battery... More to follow as I figure out more from this.

 

[Ziggy73]

That's good information, I was always wondering if I needed to buy a specific"jump" starter for an AGM battery as well. My chargers all have an AGM setting so that should be okay. I'm guessing from your info that I should be fine with a regular jump starter, also I don't think they make specific AGM jump starters.

 

[PB2021]

This link might assist to provide some detail on AGM properties
https://batteryuniversity.com/article/bu-201a-absorbent-glass-mat-agm

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