During the late 19th and early 20th centuries, the lead-acid battery emerged as a critical technology for electrical storage, particularly in telecommunications, lighting, and early automotive applications. As adoption grew, the need for standardization became apparent to ensure compatibility, reliability, and interchangeability across different manufacturers and industries. Engineering societies and industry groups played a pivotal role in establishing early conventions for voltages, sizes, and terminology before 1930.

The earliest lead-acid batteries, following Planté's and Faure's developments in the 1880s, were largely custom-built for specific applications. However, as demand increased, inconsistencies in voltage ratings, plate dimensions, and terminal configurations created inefficiencies. By the 1890s, organizations such as the American Institute of Electrical Engineers (AIEE) and the British Engineering Standards Association (BESA) began addressing these challenges through collaborative efforts with manufacturers.

One of the first areas of standardization was nominal voltage per cell. Early lead-acid cells typically operated around 2 volts, but variations existed due to differences in plate composition and electrolyte concentration. By the 1910s, industry consensus solidified around 2 volts as the standard nominal voltage for a single lead-acid cell, with multi-cell batteries configured in whole-number multiples (e.g., 6V, 12V). This convention simplified system design, particularly for automotive and stationary applications.

Physical dimensions also saw early standardization, particularly for stationary batteries used in telegraphy and backup power. The Edison Electric Illuminating Company and other utilities pushed for uniform jar sizes and plate counts to streamline maintenance and replacement. Common configurations included:

- Telegraph batteries: Typically 60-100 ampere-hours, with standardized jar heights and widths to fit relay racks.
- Lighting batteries: Often 12V or 24V systems, with plate thicknesses standardized to balance capacity and durability.
- Automotive batteries: Early sizes were influenced by the Society of Automotive Engineers (SAE), which recommended terminal placements to prevent polarity confusion.

Terminology was another critical focus. Before standardization, terms like "accumulator," "secondary cell," and "storage battery" were used interchangeably, leading to confusion. By the 1920s, industry publications and engineering societies promoted consistent language:

- "Lead-acid battery" became the preferred term over "accumulator."
- "Ampere-hour" was universally adopted for capacity measurement, replacing less precise terms like "cell size."
- "Specific gravity" was standardized as the metric for electrolyte concentration, with hydrometer readings normalized to 1.210-1.280 for fully charged conditions.

Manufacturers such as Gould, Exide, and Chloride collaborated through trade associations to align production practices. The National Electrical Manufacturers Association (NEMA), founded in 1926, further codified these standards, publishing guidelines for plate thickness, separator materials, and terminal designs. These efforts reduced variability and improved cross-brand compatibility.

Testing protocols also evolved during this period. The AIEE established baseline procedures for capacity verification, such as discharging batteries at a constant current (e.g., 8-hour or 20-hour rates) to a defined cutoff voltage. This allowed for meaningful performance comparisons between products.

Despite these advances, regional differences persisted. European manufacturers often favored metric dimensions, while U.S. firms used imperial measurements. However, the foundational work of early standardization bodies laid the groundwork for later harmonization. By 1930, lead-acid batteries had achieved a remarkable degree of uniformity in key parameters, enabling broader technological adoption and interoperability.

The pre-1930 standardization efforts were driven by practical necessity rather than regulatory mandates. Engineers and manufacturers recognized that consistent specifications reduced costs, improved reliability, and accelerated innovation. These early conventions remain embedded in modern lead-acid battery design, a testament to their enduring utility.