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MAY 2026 I SMT007 MAGAZINE 53 gence of high-voltage power electronics, outdoor- rated electronic assemblies, software-driven control systems, and grid-connected infrastructure. Public charging infrastructure is at the intersection of automotive, industrial, and utility electronics. Reliability is the cumulative result of numerous design, material, process, and validation decisions made long before a charger is installed in the field. Engineering high-uptime EV charging infrastruc- ture requires a mindset shift where uptime must be treated as a core design requirement, equal in importance to power level, efficiency, and cost. Engineering Reliability Across Charging Architectures EV charging technologies differ substantially in power level, architecture, and reliability exposure. AC Level 1 and Level 2 charging rely heavily on the vehicle's onboard charger, shifting much of the power electronics burden onto the vehicle itself. As a result, AC charging infrastructure is comparatively simple and operates at lower power levels. These systems have historically demonstrated higher inherent reliability, though they remain vulnerable to connector wear, nuisance ground-fault interrup- tions, relay failures, and grid-side disturbances, particularly in outdoor and multi-unit residential installations. 2 Level 3 DC fast charging (DCFC) introduces a fundamentally different reliability profile. These systems integrate high-voltage rectifi- cation, power factor correction, galvanic isolation, and ad- vanced thermal management directly within the charging station, typically op- erating at 400–800 V and with power levels up to 350 kW. This architecture dra- matically increases sensitivity to thermal cycling, moisture in- gress, contamination, and insulation coordination failures, making DCFC reliability disproportionately dependent on design for reliability (DFR) practices long used in automo- tive and industrial power electronics. 3 Wireless and smart charging architectures further increase system complexity. Inductive charging removes mechanical connectors but introduces alignment sensitivity, EMC challenges, and addi- tional control electronics. Smart and bi-directional charging systems depend heavily on software integrity, protocol interoperability, and communica- tions reliability. These are areas where failures can disable otherwise functional hardware. Each charging architecture introduces distinct reliability risks, but in all cases, uptime is governed by electronics design, materials, and manufactur- ing discipline. Reliability Expectations Meet Field Reality In electronics manufacturing, uptime is often treated as a downstream performance indicator. In EV charging infrastructure, that approach no longer works. Regulatory programs such as the U.S. National Electric Vehicle Infrastructure (NEVI) initiative now mandate 97% operational uptime, transforming uptime into a compliance-driven Figure 1. Level 2 charger. (Source: Adobe Stock) Figure 2: Level 3 DC fast charger. (Source: Creative Commons, Kgbo, 2020)