SEATTLE — Heliox, a Siemens business, has announced a partnership with King County Metro in Washington state to pilot its newly introduced Heliox Flex Pro™ charger. The pilot is designed to support King County Metro’s electric bus charging infrastructure as the transit agency continues expanding its zero-emission fleet operations.
King County Metro serves Seattle and 34 surrounding municipalities and operates bus, trolley, on-demand, paratransit, vanpool, and water taxi services, as well as the Seattle Streetcar, Sound Transit Link light rail, and Sound Transit Express buses. As the highest-ridership transit agency in the Northwestern United States, it needs reliable, high-performance charging systems to support a complex and demanding network.
High-Power Density
The Heliox Flex Pro delivers up to 480 kW of power in a compact footprint of just 12 square feet, making it well suited to high-density transit depots where space is limited.
Integrated with an overhead pantograph, the system can charge battery-electric buses from 20% to 80% state of charge in about one hour. King County Metro Project Manager Kevin Kibet said the agency appreciates the opportunity to continue piloting charging solutions as it learns about the latest options on the market.
Operational Flexibility
The system supports CCS1 charging at 250A, as well as inverted pantograph configurations at 250A or 600A. It can distribute power in 80 kW increments across up to six outlets and serve up to six vehicles at the same time, with either dynamic or static power sharing depending on site needs.
Flex Pro is backward-compatible with existing Flex dispensers and includes built-in support for future expansion. A modular power architecture helps keep charging sessions running at slightly reduced output if a power module or group fails, supporting fleet uptime.
Installation and Procurement
The cabinet is designed for front-only access, which simplifies installation and maintenance and gives depots more flexibility in site layout. Heliox also offers a 24-month warranty, preventative maintenance options, and both Build America, Buy America-compliant and non-compliant versions.
The pilot adds another data point for transit agencies looking to deploy compact, high-power electric bus charging infrastructure without sacrificing flexibility or service reliability.
