Principal Battery Systems Engineer

We're looking for a Principal Engineer to set the technical direction for our BESS product line and to own the product roadmap across multiple concurrent development cycles. This is the senior technical voice on the product team: you'll architect new products, resolve the hardest engineering trade-offs, set the engineering standards others work to, and represent ON.energy's product engineering externally — to vendors, customers, certifying bodies, and the broader industry. You should be comfortable operating with minimal direction, holding the bar on technical quality, and moving multiple product cycles forward in parallel without losing the thread on any of them.

• Bachelor's degree in Electrical Engineering, Power Electronics, or a closely related technical field. MS preferred.
• 10+ years of hands-on engineering experience in BESS, power electronics, UPS, or comparable mission-critical industrial power systems, with a demonstrated record of operating with minimal direction in a senior technical role.
• Owned multiple product development cycles end-to-end and independently. You've personally designed and integrated a BESS at the system level, from engineering through commissioning and into live operation, not just handed it off at FAT, and the products are still in the field.
• Architecture-level decision authority on previous BESS equipment. You've made the trade-off calls others built around, not just executed someone else's architecture.
• Deep, demonstrable skill in detailed component sizing — fuse coordination, busbar sizing, protection device selection, thermal sizing for enclosed cabinets — at the level required to sign off on production designs.
• Fluency producing and reviewing SLDs, GAs, schematics, and panel layouts; expert with AutoCAD or equivalent E-CAD; comfortable across mechanical drawings.
• Strong track record running strategic vendor relationships through design, FAT, serial production, and post-deployment escalation.
• Excellent written and verbal communication — specs, technical positions, design review leadership, board-level briefings.
• Willing to travel up to 25–30% for FAT inspections, site commissioning, customer engagements, and vendor reviews.
• Direct experience with data center / UPS / mission-critical power or utility-scale BESS at the architecture level.
• Active involvement in standards bodies (UL, IEC, NFPA, IEEE working groups, CSA TC committees) or technical conference contributions.
• Patents, peer-reviewed publications, or other evidence of recognized technical depth in the field.
• PE license.
• Familiarity with UL 9540 / 9540A, NFPA 855, IEC 62619, IEEE 1547, NEC Article 706, plus the relevant codes for target markets.
• Experience standing up or scaling structured PLM, ECR/ECN, and design-review processes.
• Multi-domain depth — BMS / cell engineering, PCS / power electronics, thermal / mechanical — alongside the EE core.