Thickness of the Positive plate matters because of a factor called “positive grid corrosion”. The positive plate gets “eaten” away gradually over time, until it all falls to the bottom as sediment. Batteries with thicker plates will last the longest.
The negative plate in batteries expands during discharge, which is why nearly all batteries have separators, such as glass mat or paper, that can be compressed.
Automotive batteries typically have plates about .040″ (4/100″) thick, while forklift batteries may have plates more than 1/4″ (.265″ for example in larger Rolls-Surrette) thick – almost 7 times as thick as auto batteries.
The typical golf cart will have plates that are around .07 to .11″ thick. The Concorde AGM’s are .115″, The Rolls-Surrette L-16 type (CH460) is .150″, and the US Battery and Trojan L-16 types are .090″. The Crown L-16HC size has .22″ thick plates. While plate thickness is not the only factor in how many deep cycles a battery can take before it dies, it is the most important one.
Most industrial deep-cycle batteries use Lead-Antimony plates rather than the Lead-Calcium used in AGM or gelled deep-cycle batteries. The Antimony increases plate life and strength, but increases gassing and water loss. This is why most industrial batteries have to be checked often for water level if you do not have Hydrocaps. The self discharge of batteries with Lead-Antimony plates can be high – as much as 1% per day on an older battery.
