Additional Reactions of Significance Oxygen Reaction Cycle:: ½O 2 + Pb PbO PbO + H 2 SO 4 PbSO 4 + H 2 O Note: Oxygen reaction cycle is a benchmark characteristic of VRLA batteries. It is more pronounced with AGM than with gel constructions. Severe Overcharge Reaction: 2H 2 O O 2 + 4H + + 4e - Note: This results in water loss due to venting of O 2 and can be life limiting. Positive Grid Corrosion: Pb + 2H 2 O PbO 2 + 4H + + 2e - Note: This results in water loss and can be life limiting. C C C C Battery Basics-Cell Chemistry

Optima AGM Battery Construction Optima has lower internal resistance compared to flat plate batteries Optima has less internal parts (~30) vs traditional batteries (120+) Optima has over the partition, solid lead connectors vs through the partition inter-cell welds

Factors affecting internal resistance of the battery –Size of lead conductors –Plate surface area –Plate spacing –Separator resistivity –Electrolyte type Gel has higher resistance than flooded or AGM designs which negatively impacts high rate and cold performance –Electrolyte concentration –Temperature Element Characteristics

Container/Cover Design Cylindrical cells provide superior mechanical structure to battery –Eliminates cell bulge –Permits higher valve pressures, 7-8 psi, compared to flat plate, 1-5 psi Flat plate batteries can experience end wall bulge when pressure builds up on charge resulting in loss of performance

Gassing Characteristics Gassing –Less than flat plate/prismatic design Why? –Higher purity materials – 99.99% pure lead –Alloys – Optima uses a binary tin lead alloy compared to a flooded battery that uses a multi component alloy (silver, tin, calcium, aluminum, etc… less impurities) –Oxygen reaction cycle Source: AGM Development Team

The Optima Advantage Longer run time