S2 Glass Composite Grids Target Longer-Life Lead-Acid Batteries

Updated on August 15, 2026 • 4 min read

Terra Supreme Battery is using AGY’s S2 Glass fiber in composite grids for its new Group 31 bipolar lead-acid battery, applying high-strength glass fiber reinforcement to address one of the long-standing durability challenges associated with lead-acid battery systems.

The battery combines pure lead with S2 Glass fiber reinforcement to produce dimensionally stable composite grids designed to retain their structural integrity through repeated charging and discharging cycles.

According to AGY, S2 Glass offers approximately 10 times the strength of steel by weight, giving Terra Supreme a lightweight reinforcement for securing the battery’s active material.

Composite Grids Address Active-Material Shedding

A central objective of Terra Supreme’s design is reducing positive active-material shedding.

In conventional lead-acid batteries, deterioration and loss of active material from the positive plate can contribute to declining capacity and eventual battery failure.

Terra Supreme says its reinforced composite-grid architecture structurally secures the active material, eliminating positive active-material shedding in its battery design.

This is where S2 Glass performs a structural rather than merely weight-saving role.

The reinforcement provides the strength and dimensional stability needed for the internal grid to maintain its geometry as the battery passes through repeated operating cycles.

Patrick Hunter, chief commercial officer and president of AGY, says the application demonstrates how advanced glass fiber reinforcement can be introduced into an established battery chemistry to address persistent performance limitations.

Bipolar Architecture Changes the Internal Battery Design

The composite grid forms part of a broader redesign of the traditional lead-acid battery.

Terra Supreme uses a bipolar architecture with horizontally oriented plates, combined with a more direct internal current path and no conventional internal busbars.

According to the company, the battery has been engineered as a direct Group 31 replacement, meaning it can operate with existing charging systems without requiring charging-system modifications.

For fleet, industrial and other applications already using Group 31 batteries, maintaining compatibility could simplify adoption compared with changing to an entirely different battery architecture or chemistry.

Battery Targets Up to 4,000 Cycles

Terra Supreme reports several performance specifications for its Group 31 battery:

• 1,200 cold-cranking amps
• 1,800 marine-cranking amps
• 3,000 pulse hot-cranking amps
• 240 minutes reserve capacity
• Up to 4,000 cycles at 60% depth of discharge

The battery is being positioned for applications requiring both high-power engine starting and deep-cycle operation.

Target markets include commercial transportation, emergency vehicles, industrial and agricultural equipment, aerospace, military systems, marine vessels, recreational vehicles, railroads and stationary energy storage.

Advanced Composites Move Inside Energy-Storage Systems

Composite materials are commonly associated with battery enclosures, protective structures and lightweight vehicle components. Terra Supreme’s application is different because the composite reinforcement is being incorporated directly into the internal electrochemical architecture of the battery.

Rather than replacing lead-acid chemistry, the approach uses glass fiber reinforcement to modify how the existing chemistry is mechanically supported.

Terra Supreme CTO Benny E. Jay says the strength and dimensional stability of S2 Glass enable the company to secure the active material and extend service life while retaining a familiar and recyclable lead-acid battery chemistry.

The application illustrates another direction for advanced composites in energy storage: using reinforcement materials not only to reduce external structural weight, but also to improve the mechanical stability and durability of components operating inside the battery itself.

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