Alkaline electrolysers are a proven and cost-efficient technology for large-scale hydrogen production. While established, improving their performance remains an active research area. A significant but less recognized factor is the internal geometry of electrode supports, which influences gas removal and mass transport, thereby affecting efficiency. This study details the design, fabrication, and experimental validation of three unique alkaline electrolysers, each featuring a modified internal electrode-support geometry. Their performance was comprehensively assessed through polarization curve analysis in individual, partial, and global configurations. The development followed the Advanced Product Quality Planning (APQP) methodology, employing pure nickel electrodes for stability. The research experimentally demonstrates how specific geometric alterations directly influence electrochemical performance and overall efficiency. By operating three electrolysers simultaneously, the system achieved an overall efficiency of 42% and a maximum oxyhydrogen production rate of 10 L min-1 with minimal electrolyte carryover This systematic work establishes essential design guidelines aimed at advancing the technology from Technology Readiness Level (TRL) 5 to TRL 6, facilitating the development of a reliable 5 kW hydrogen production system.